MedWorm: Bumetanide

Blocking seizures with the diuretic bumetanide: Promises and pitfalls

Epilepsia — Wed, 01 Feb 2012 05:00:00 +0100

(Source: Epilepsia)

MedWorm Sponsor Message: Find the best January Sales in the UK.

Ischemia-induced stimulation of cerebral microvascular endothelial cell Na-K-Cl cotransport involves p38 and JNK MAP kinases

AJP: Cell Physiology — Tue, 24 Jan 2012 05:00:00 +0100

We report that p38 and JNK are present in cultured cerebral microvascular endothelial cells and in BBB endothelial cells in situ and that hypoxia (7% O2 and 2% O2), aglycemia, AVP, and O2-glucose deprivation (5- to 120-min exposures) all rapidly activate p38 and JNK in the cells. We also provide evidence that SB-239063 and SP-600125 reduce or abolish ischemic factor stimulation of BBB NKCC activity. These findings support the hypothesis that ischemic factor stimulation of the BBB NKCC involves activation of p38 and JNK MAPKs. (Source: AJP: Cell Physiology)

Cotransport of water by Na+-K+-2Cl- cotransporters expressed in Xenopus oocytes: NKCC1 versus NKCC2.

The Journal of Physiology — Mon, 16 Jan 2012 05:00:00 +0100

Authors: Zeuthen T, Macaulay N Abstract The NKCC1 and NKCC2 isoforms of the mammalian Na+-K+-2Cl- cotransporter were expressed in Xenopus oocytes and the relation between external ion concentration and water fluxes determined. Water fluxes were determined from changes in the oocytes volume and ion fluxes from 86Rb+ uptake. Isotonic increases in external K+ concentration elicited abrupt inward water fluxes in the NKCC1; the K+ dependence obeyed one-site kinetics with a K0.5 of 7.5 mM. The water fluxes were blocked by bumetanide, had steep temperature dependence and could proceed uphill against an osmotic gradient of 20 mOsm. A comparison between ion and water fluxes indicates that 460 water molecules are cotransported for each turnover of the protein. In contrast, the NKCC2 did not ...

GPR35 Is a Target of the Loop Diuretic Drugs Bumetanide and Furosemide

Pharmacology — Mon, 09 Jan 2012 23:00:00 +0100

Pharmacology 2012;89:13–17 (DOI:10.1159/000335127) (Source: Pharmacology)

Updated IV monograph on Bumetanide

NeLM - News — Fri, 23 Dec 2011 05:00:00 +0100

Source: Medusa Area: News An updated IV monograph on Bumetanide is now available from the NHS injectable medicines guide website (Medusa). Please see the link below for access (registration required). (Source: NeLM - News)

Loss-of-function and gain-of-function phenotypes of stomatocytosis mutant RhAG F65S

AJP: Cell Physiology — Wed, 30 Nov 2011 05:00:00 +0100

Four patients with overhydrated cation leak stomatocytosis (OHSt) exhibited the heterozygous RhAG missense mutation F65S. OHSt erythrocytes were osmotically fragile, with elevated Na and decreased K contents and increased cation channel-like activity. Xenopus oocytes expressing wild-type RhAG and RhAG F65S exhibited increased ouabain and bumetanide-resistant uptake of Li+ and 86Rb+, with secondarily increased 86Rb+ influx sensitive to ouabain and to bumetanide. Increased RhAG-associated 14C-methylammonium (MA) influx was severely reduced in RhAG F65S-expressing oocytes. RhAG-associated influxes of Li+, 86Rb+, and 14C-MA were pharmacologically distinct, and Li+ uptakes associated with RhAG and RhAG F65S were differentially inhibited by NH4+ and Gd3+. RhAG-expressing oocytes were acidified a...

MedWorm Sponsor Message: Please support the Doctors In Chains campaign for the medics tortured and sentenced for up to 15 years in Bahrain. #FreeDoctors

Ischemia-induced stimulation of cerebral microvascular endothelial cell Na-K-Cl cotransport involves p38 and JNK MAP kinases.

Am J Physiol Cell Ph... — Wed, 02 Nov 2011 04:00:00 +0100

Authors: Wallace BK, Jelks KA, O'Donnell ME Abstract Previous studies have provided evidence that in the early hours of ischemic stroke a luminal membrane blood-brain barrier (BBB) Na-K-Cl cotransporter (NKCC) participates in ischemia-induced cerebral edema formation. Inhibition of BBB NKCC activity by intravenous bumetanide significantly reduces edema and infarct in the rat permanent middle cerebral artery occlusion (MCAO) model of ischemic stroke. We have demonstrated previously that the BBB cotransporter is stimulated by hypoxia, aglycemia and arginine vasopressin (AVP), factors present during cerebral ischemia. However, the underlying mechanisms have not been known. Ischemic conditions have been shown to activate p38 and JNK MAP kinases (MAPKs) in brain and the p38 and JNK inhi...

Is it safe to use a diuretic to treat seizures early in development ?

Epilepsy Curr — Tue, 01 Nov 2011 04:00:00 +0100

Authors: Ben-Ari Y, Tyzio R Abstract There has been considerable interest in using bumetanide, a diuretic chloride importer NKCC1 antagonist, to reduce intracellular chloride ([Cl(-)](i)) in epileptic neurons, thereby shifting the polarity of GABA from excitatory to inhibitory and ameliorating the actions of GABA-acting antiepileptic drugs. However, a recent study raises the important issue of potential deleterious actions of bumetanide on immature neurons, because reduction of (Cl(-))(i) also alleviates a major source of excitation in developing neurons, upon which GABA exerts a trophic action. This review considers the importance of separating intrauterine from postnatal effects of bumetanide in normal versus pathologic neurons. PMID: 22131900 [PubMed - in process] (Source: E...

Bumetanide

Practical Diabetes International — Tue, 01 Nov 2011 04:00:00 +0100

(Source: Practical Diabetes International)

Altered inhibition in tuberous sclerosis and type IIb cortical dysplasia

Annals of Neurology — Tue, 01 Nov 2011 04:00:00 +0100

AbstractObjective:The most common neurological symptom of tuberous sclerosis complex (TSC) and focal cortical dysplasia (FCD) is early‐life refractory epilepsy. As previous studies have shown enhanced excitatory glutamatergic neurotransmission in TSC and FCD brains, we hypothesized that neurons associated with these lesions may also express altered GABAA receptor (GABAAR)‐mediated inhibition.Methods:Expression of the GABAAR subunits α? and α4, the Na+‐K+‐2Cl‐ (NKCC1), and the K+‐ Cl‐ (KCC2) transporters in human TSC and FCD Type II specimens were analyzed by Western blot and double label immunocytochemistry. GABAAR responses in dysplastic neurons from a single case of TSC were measured by perforated‐patch recording and compared to normal‐appearing cortical neurons from ...

Role of NKCC in BK channel-mediated net K+ secretion in the CCD

AJP: Renal Physiology — Mon, 31 Oct 2011 04:00:00 +0100

Apical SK/ROMK and BK channels mediate baseline and flow-induced K secretion (FIKS), respectively, in the cortical collecting duct (CCD). BK channels are detected in acid-base transporting intercalated (IC) and Na-absorbing principal (PC) cells. Although the density of BK channels is greater in IC than PC, Na-K-ATPase activity in IC is considered inadequate to sustain high rates of urinary K secretion. To test the hypothesis that basolateral NKCC in the CCD contributes to BK channel-mediated FIKS, we measured net K secretion (JK) and Na absorption (JNa) at slow (~1) and fast (~5 nl·min–1·mm–1) flow rates in rabbit CCDs microperfused in vitro in the absence and presence of bumetanide, an inhibitor of NKCC, added to the bath. Bumetanide inhibited FIKS but not basal ...

MedWorm Sponsor Message: Find the best January Sales in the UK.

With-No-Lysine Kinase 3 (WNK3) stimulates glioma invasion by regulating cell volume

AJP: Cell Physiology — Wed, 26 Oct 2011 04:00:00 +0100

In this study, we show that NKCC1 activity in gliomas requires the With-No-Lysine Kinase-3 (WNK3) kinase. Western blots of patient biopsies and patient-derived cell lines shows prominent expression of Ste-20-related, proline-alanine-rich kinase (SPAK), oxidative stress response kinase (OSR1), and WNK family members 1, 3, and 4. Of these, only WNK3 colocalized and coimmunoprecipitated with NKCC1 upon changes in cell volume. Stable knockdown of WNK3 using specific short hairpin RNA constructs completely abolished NKCC1 activity, as measured by the loss of bumetanide-sensitive cell volume regulation. Consequently, WNK3 knockdown cells showed a reduced ability to invade across Transwell barriers and lacked bumetanide-sensitive migration. This data indicates that WNK3 is an essential regulator ...

BUMETANIDE (Bumetanide) Tablet [Med Health Pharma LLC.]

DailyMed Drug Label Updates for the last seven days (since May 20, 2007 EST) — Thu, 13 Oct 2011 05:00:00 +0100

Updated Date: Oct 13, 2011 EST (Source: DailyMed Drug Label Updates for the last seven days (since May 20, 2007 EST))

Capsaicinoids Regulate Airway Anion Transporters through Rho Kinase- and Cyclic AMP-Dependent Mechanisms.

American Journal of Respiratory Cell and Molecular Biology — Sat, 01 Oct 2011 04:00:00 +0100

Authors: Hibino Y, Morise M, Ito Y, Mizutani T, Matsuno T, Ito S, Hashimoto N, Sato M, Kondo M, Imaizumi K, Hasegawa Y Abstract To investigate the effects of capsaicinoids on airway anion transporters, we recorded and analyzed transepithelial currents in human airway epithelial Calu-3 cells. Application of capsaicin (100 μM) attenuated vectorial anion transport, estimated as short-circuit currents (I(SC)), before and after stimulation by forskolin (10 μM) with concomitant reduction of cytosolic cyclic AMP (cAMP) levels. The capsaicin-induced inhibition of I(SC) was also observed in the response to 8-bromo-cAMP (1 mM, a cell-permeable cAMP analog) and 3-isobutyl-1-methylxanthine (1 mM, an inhibitor of phosphodiesterases). The capsaicin-induced inhibition of I(SC) was attributed to...

A SPAK Isoform Switch Modulates Renal Salt Transport and Blood Pressure.

Cell Metabolism — Wed, 07 Sep 2011 04:00:00 +0100

Authors: McCormick JA, Mutig K, Nelson JH, Saritas T, Hoorn EJ, Yang CL, Rogers S, Curry J, Delpire E, Bachmann S, Ellison DH Abstract The renal thick ascending limb (TAL) and distal convoluted tubule (DCT) play central roles in salt homeostasis and blood pressure regulation. An emerging model suggests that bumetanide- and thiazide-sensitive NaCl transporters (NKCC2 and NCC) along these segments are phosphorylated and activated by WNK kinases, via SPAK and OSR1. Here, we show that a kidney-specific SPAK isoform, which lacks the kinase domain, inhibits phosphorylation of NCC and NKCC2 by full-length SPAK in vitro. Kidney-specific SPAK is highly expressed along the TAL, whereas full-length SPAK is more highly expressed along the DCT. As predicted from the differential expression, SP...

Cellular localization of NKCC2 and its possible role in the Cl(-) absorption in the rat and human distal colonic epithelia.

Translational Research : the journal of laboratory and clinical medicine — Tue, 30 Aug 2011 16:08:30 +0100

In conclusion, NKCC2 is expressed widely in the colonic epithelium in rat distal colon and human sigmoid colon, especially in the apical membrane. It involves the process of colonic Cl(-) absorption coupled with HCO(3)(-) secretion. PMID: 21867980 [PubMed - in process] (Source: Translational Research : the journal of laboratory and clinical medicine)

MedWorm Sponsor Message: Please support the Doctors In Chains campaign for the medics tortured and sentenced for up to 15 years in Bahrain. #FreeDoctors

WNK2 Regulation of SLC12a Cotransporters [Neurobiology]

Journal of Biological Chemistry — Thu, 18 Aug 2011 23:00:00 +0100

NKCC1 and KCC2, related cation-chloride cotransporters (CCC), regulate cell volume and γ-aminobutyric acid (GABA)-ergic neurotranmission by modulating the intracellular concentration of chloride [Cl−]. These CCCs are oppositely regulated by serine-threonine phosphorylation, which activates NKCC1 but inhibits KCC2. The kinase(s) that performs this function in the nervous system are not known with certainty. WNK1 and WNK4, members of the WNK (with no lysine [K]) kinase family, either directly or via the downstream SPAK/OSR1 Ste20-type kinases, regulate the furosemide-sensitive NKCC2 and the thiazide-sensitive NCC, kidney-specific CCCs. What role the novel WNK2 kinase plays in this regulatory cascade, if any, is unknown. Here, we show that WNK2, unlike other WNKs, is not expressed in kidne...

Evidence for functional atypical nicotinic receptors that activate K+ dependent Cl- secretion in mouse tracheal epithelium.

Am J Respir Cell Mol... — Wed, 17 Aug 2011 23:00:00 +0100

Authors: Hollenhorst MI, Lips KS, Weitz A, Krasteva G, Kummer W, Fronius M Abstract The present study focused on the influence of nicotinic acetylcholine receptors (nAChR) on ion transport processes in mouse tracheal epithelium. RT-PCR experiments revealed expression of the α3, α4, α5, α7, α9, α10, β2 and β4 nAChR subunits in mouse tracheal epithelium. In Ussing-chamber recordings of mouse tracheae, apically applied nicotine (100 µM) induced a dose-dependent increase of the transepithelial short-circuit-current (EC50: 14.6 µM). The nicotine-induced effect (INIC) was attenuated by mecamylamine (25 µM, apical) and methyllycaconitine (1 µM, apical). The nAChR agonist 1.1-Dimethyl-4-phenylpiperatinium iodide (DMPP, 100 µM) revealed apical and basolateral location of the re...

Loss-of-function and gain-of-function phenotypes of stomatocytosis mutant RhAG F65S.

Am J Physiol Cell Ph... — Tue, 16 Aug 2011 23:00:00 +0100

Authors: Stewart AK, Shmukler BE, Vandorpe DH, Rivera A, Heneghan JF, Li X, Hsu A, Karpatkin M, O'Neill AF, Bauer DE, Heeney MM, John K, Kuypers FA, Gallagher PG, Lux SE, Brugnara C, Westhoff CM, Alper SL Abstract Four patients with overhydrated cation leak stomatocytosis (OHSt) exhibited the heterozygous RhAG missense mutation F65S. OHSt erythrocytes were osmotically fragile, with elevated Na and decreased K contents and increased cation channel-like activity. Xenopus oocytes expressing wildtype RhAG and RhAG F65S exhibited increased ouabain and bumetanide-resistant uptake of Li(+) and (86)Rb(+), with secondarily increased (86)Rb(+) influx sensitive to ouabain and to bumetanide. Increased RhAG-associated (14)C-methylammonium (MA) influx was severely reduced in RhAG F65S-expressing...

Altered GABA Signaling in Early Life Epilepsies.

Neural Plasticity — Thu, 11 Aug 2011 20:15:02 +0100

Authors: Briggs SW, Galanopoulou AS The incidence of seizures is particularly high in the early ages of life. The immaturity of inhibitory systems, such as GABA, during normal brain development and its further dysregulation under pathological conditions that predispose to seizures have been speculated to play a major role in facilitating seizures. Seizures can further impair or disrupt GABA(A) signaling by reshuffling the subunit composition of its receptors or causing aberrant reappearance of depolarizing or hyperpolarizing GABA(A) receptor currents. Such effects may not result in epileptogenesis as frequently as they do in adults. Given the central role of GABA(A) signaling in brain function and development, perturbation of its physiological role may interfere with neuronal morpholog...

Expression of Na(+)-K(+)-2Cl(-) Cotransporter 1 Is Epigenetically Regulated During Postnatal Development of Hypertension.

American Journal of Hypertension — Wed, 03 Aug 2011 23:00:00 +0100

ConclusionIt is concluded that expression of NKCC1 is epigenetically upregulated during postnatal development of hypertension. Our data indicate that maintenance of hypomethylation in Nkcc1 promoter of SHR resulting from low DNMT activity plays an important role in the upregulation of NKCC1 during development of spontaneous hypertension.American Journal of Hypertension (2011). doi:10.1038/ajh.2011.136. PMID: 21814290 [PubMed - as supplied by publisher] (Source: American Journal of Hypertension)

MedWorm Sponsor Message: Find the best January Sales in the UK.

Role of NKCC in BK channel-mediated net K+ secretion in the CCD.

American Journal of Physiology. Renal Physiology — Tue, 02 Aug 2011 23:00:00 +0100

Authors: Liu W, Schreck C, Coleman RA, Wade JB, Hernandez Y, Zavilowitz B, Warth R, Kleyman TR, Satlin LM Apical SK/ROMK and BK channels mediate baseline and flow-induced (FIKS) K secretion, respectively, in the cortical collecting duct (CCD). BK channels are detected in acid-base transporting intercalated (IC) and Na absorbing principal (PC) cells. Although the density of BK channels is greater in ICs than PCs, Na-K-ATPase activity in ICs is considered inadequate to sustain high rates of urinary K secretion. To test the hypothesis that basolateral NKCC in the CCD contributes to BK channel-mediated FIKS, we measured net K secretion (JK) and Na absorption (JNa) at slow (1) and fast (~5 nl•min(-1)•mm(-1)) flow rates in rabbit CCDs microperfused in vitro in the absence and presence of...

With-No-Lysine Kinase 3 (WNK3) Stimulates Glioma Invasion By Regulating Cell Volume.

American Journal of Physiology. Cell Physiology — Tue, 02 Aug 2011 23:00:00 +0100

In this study, we show that NKCC1 activity in gliomas requires the WNK3 kinase. Western blots of patient biopsies and patient-derived cell lines shows prominent expression of Ste-20-related, proline-alanine rich kinase (SPAK), oxidative stress response kinase (OSR1), and WNK family members 1, 3, and 4. Of these, only WNK3 colocalized and co-immunoprecipitated with NKCC1 upon changes in cell volume. Stable knockdown of WNK3 using specific shRNA constructs completely abolished NKCC1 activity, as measured by the loss of bumetanide-sensitive cell volume regulation. Consequently, WNK3 knockdown cells showed a reduced ability to invade across Transwell barriers and lacked bumetanide-sensitive migration. This data indicates that WNK3 is an essential regulator of NKCC1 and that WNK3 activates NKCC...

Ischemia-induced stimulation of Na-K-Cl cotransport in cerebral microvascular endothelial cells involves AMP kinase

AJP: Cell Physiology — Tue, 26 Jul 2011 23:00:00 +0100

Increased blood-brain barrier (BBB) Na-K-Cl cotransporter activity appears to contribute to cerebral edema formation during ischemic stroke. We have shown previously that inhibition of BBB Na-K-Cl cotransporter activity reduces edema and infarct in the rat middle cerebral artery occlusion (MCAO) model of ischemic stroke. We have also shown that the BBB cotransporter is stimulated by the ischemic factors hypoxia, aglycemia, and arginine vasopressin (AVP), although the mechanisms responsible are not well understood. AMP-activated protein kinase (AMPK), a key mediator of cell responses to stress, can be activated by a variety of stresses, including ischemia, hypoxia, and aglycemia. Previous studies have shown that the AMPK inhibitor Compound C significantly reduces infarct in mouse MCAO. The ...

The flavonone naringenin inhibits chloride secretion in isolated colonic epithelia.

European Journal of Pharmacology — Thu, 07 Jul 2011 23:00:00 +0100

Authors: Collins D, Kopic S, Geibel JP, Hogan AM, Medani M, Baird AW, Winter DC Studies investigating the activating and inhibitory actions of bioflavonoids on colonic function have yielded conflicting results. At low concentrations, flavonoids may stimulate chloride secretion while at higher concentrations they may have antisecretory actions in the colon. Naringenin (4',5,7-trihydroxyflavanone), found predominantly in citrus fruits, confers a protective effect against colorectal cancer and is purported to modulate secretory function in colonic cell lines. The aim of this study was to investigate the effects of naringenin on ion transport in rat and human colonic mucosae. Naringenin inhibited basal and stimulated chloride secretion in rat and human colonic mucosae mounted in Ussing cha...

Tumor necrosis factor-{alpha} is an endogenous inhibitor of Na+-K+-2Cl- cotransporter (NKCC2) isoform A in the thick ascending limb

AJP: Renal Physiology — Tue, 05 Jul 2011 23:00:00 +0100

The effects of TNF gene deletion on renal Na+-K+-2Cl– cotransporter (NKCC2) expression and activity were determined. Outer medulla from TNF–/– mice exhibited a twofold increase in total NKCC2 protein expression compared with wild-type (WT) mice. This increase was not observed in TNF–/– mice treated with recombinant human TNF (hTNF) for 7 days. Administration of hTNF had no effect on total NKCC2 expression in WT mice. A fourfold increase in NKCC2A mRNA accumulation was observed in outer medulla from TNF–/– compared with WT mice; NKCC2F and NKCC2B mRNA accumulation was similar between genotypes. The increase in NKCC2A mRNA accumulation was attenuated when TNF–/– mice were treated with hTNF. Bumetanide-sensitive O2 consumption, an in vitro...

MedWorm Sponsor Message: Please support the Doctors In Chains campaign for the medics tortured and sentenced for up to 15 years in Bahrain. #FreeDoctors

Ion transport mechanisms linked to bicarbonate secretion in the esophageal submucosal glands

AJP: Regulatory, Integrative and Comparative Physiology — Thu, 30 Jun 2011 23:00:00 +0100

This study characterized the ion transport mechanisms linked to HCO3– secretion in SMG. We localized ion transporters using immunofluorescence, and we examined their expression by RT-PCR and in situ hybridization. We measured HCO3– secretion by using pH stat and the isolated perfused esophagus. Using double labeling with Na+-K+-ATPase as a marker, we localized Na+-coupled bicarbonate transporter (NBCe1) and Cl–-HCO3– exchanger (SLC4A2/AE2) to the basolateral membrane of duct cells. Expression of cystic fibrosis transmembrane regulator channel (CFTR) was confirmed by immunofluorescence, RT-PCR, and in situ hybridization. We identified anion exchanger SLC26A6 at the ducts' luminal membrane and Na+-K+-2Cl– (NKCC1) at the basolateral membrane of mucous and duct ce...

Emodin induces chloride secretion in rat distal colon through activation of mast cells and enteric neurons

British Journal of Pharmacology — Wed, 29 Jun 2011 23:00:00 +0100

Conclusions and implications: The results suggest that emodin‐induced colonic Cl‐ secretion involves mast cell degranulation and activation of cholinergic and non cholinergic submucosal neurons. (Source: British Journal of Pharmacology)

Effects of estradiol on ischemic factor-induced astrocyte swelling and AQP4 protein abundance

AJP: Cell Physiology — Sun, 26 Jun 2011 23:00:00 +0100

In this study, we evaluated the effects of AVP (100 nM), hypoxia (7.5% O2), aglycemia, hypoxia (2%)/aglycemia [oxygen glucose deprivation (OGD)], and estradiol (1–100 nM) on astrocyte cell volume using 3-O-methyl-d-[3H]glucose equilibration methods. We found that AVP, hypoxia, aglycemia, and OGD (30 min to 5 h) each significantly increased astrocyte cell volume, and that estradiol (30–180 min) abolished swelling induced by AVP or hypoxia, but not by aglycemia or OGD. Bumetanide and/or HOE-642 also abolished swelling induced by AVP but not aglycemia. Abundance of aquaporin-4, known to participate in ischemia-induced astrocyte swelling, was significantly reduced following 7-day but not 2- or 3-h estradiol exposures. Our findings suggest that hypoxia, aglycemia, and AVP each contr...

What medicines should be avoided by patients suffering from "sulfa-allergy"?

NeLM - Medicines Q and A — Thu, 09 Jun 2011 23:00:00 +0100

Source: East Anglia Medicines Information Service Area: Evidence > Medicines Q & A "Sulfa-allergy", also referred to as allergy to "sulfa drugs", is often used as a catch-all term for patients suffering from an allergy to drugs containing the sulfonamide chemical group. Approximately 3% of the general population in the United States (UK population figures unavailable) have an allergy to sulfonamide antimicrobials. It is advisable for patients with an allergy to sulfonamides to avoid drugs from the following list: Sulfonamide antibacterials: sulfadiazine (inc. silver sulfadiazine), sulfamethoxazole (co-trimoxazole). Sulfasalazine Sulfonylurea antidiabetics: gliclazide, glipizide, glibenclamide, glimepiride, chlorpropamide and tolbutamide. Diuretics: thiazide...

Anomalous levels of Cl− transporters cause a decrease of GABAergic inhibition in human peritumoral epileptic cortex

Epilepsia — Wed, 01 Jun 2011 23:00:00 +0100

We report that the positive shift of EGABA in epileptic peritumoral human cortex is due to an altered expression of NKCC1 and KCC2, perturbing Cl− homeostasis, which might lead to a consequent reduction in GABAergic inhibition. These findings point to a key role of Cl− transporters KCC2 and NKCC1 in tumor‐related epilepsy, suggesting a more specific drug therapy and surgical approaches for the epileptic patients afflicted by brain tumors. (Source: Epilepsia)

MedWorm Sponsor Message: Find the best January Sales in the UK.

Antiepileptic effects of endogenous beta-hydroxybutyrate in suckling infant rats

Epilepsy Research — Tue, 31 May 2011 23:00:00 +0100

Summary: Physiological ketosis is a hallmark of metabolism in suckling infants. However, little is known on the impact of physiological ketosis on brain excitability. We addressed this question in suckling rats in vivo. 16-channel extracellular field potential recordings were performed from somatosensory barrel cortex at postnatal days 5–9 non-anaesthetized rat pups. Seizures were induced by the volatile convulsant agent flurothyl. One hour after blockade of physiological ketogenesis using combined administration of beta-oxidation inhibitors mercaptoacetate, insulin and glucose to prevent hypoglycemia, we found no significant change in the flurothyl-induced electrographic seizures. However, build-up of seizures during two repetitive flurothyl applications was strongly aggravated in the a...

Two-photon microscopy and fluorescence lifetime imaging reveal stimulus-induced intracellular Na+ and Cl- changes in cockroach salivary acinar cells

AJP: Cell Physiology — Wed, 25 May 2011 23:00:00 +0100

The intracellular ion homeostasis in cockroach salivary acinar cells during salivation is not satisfactorily understood. This is mainly due to technical problems regarding strong tissue autofluorescence and ineffective ion concentration quantification. For minimizing these problems, we describe the successful application of two-photon (2P) microscopy partly in combination with fluorescence lifetime imaging microscopy (FLIM) to record intracellular Na+ and Cl– concentrations ([Na+]i, [Cl–]i) in cockroach salivary acinar cells. Quantitative 2P-FLIM Cl– measurements with the dye N-(ethoxycarbonylmethyl)-6-methoxy-quinolinium bromide indicate that the resting [Cl–]i is 1.6 times above the Cl– electrochemical equilibrium but is not influenced by pharmacological inh...

Cellular localization of NKCC2 and its possible role in the Cl− absorption in the rat and human distal colonic epithelia

Translational Research — Thu, 19 May 2011 23:00:00 +0100

In conclusion, NKCC2 is expressed widely in the colonic epithelium in rat distal colon and human sigmoid colon, especially in the apical membrane. It involves the process of colonic Cl− absorption coupled with HCO3− secretion. (Source: Translational Research)

Ischemia-induced stimulation of Na-K-Cl cotransport in cerebral microvascular endothelial cells involves AMP kinase.

American Journal of Physiology. Cell Physiology — Tue, 10 May 2011 23:00:00 +0100

Authors: Wallace BK, Foroutan S, O'Donnell ME Increased blood-brain barrier (BBB) Na-K-Cl cotransporter activity appears to contribute to cerebral edema formation during ischemic stroke. We have shown previously that inhibition of BBB Na-K-Cl cotransporter activity reduces edema and infarct in the rat middle cerebral artery occlusion (MCAO) model of ischemic stroke. We have also shown that the BBB cotransporter is stimulated by the ischemic factors hypoxia, aglycemia and arginine vasopressin (AVP), although the mechanisms responsible are not well understood. AMP-activated protein kinase (AMPK), a key mediator of cell responses to stress, can be activated by a variety of stresses, including ischemia, hypoxia and aglycemia. Previous studies have shown that the AMPK inhibitor Compound C s...

Mechanisms of chloride in cardiomyocyte anoxia-reoxygenation injury: the involvement of oxidative stress and NF-kappaB activation.

Molecular and Cellular Biochemistry — Sat, 07 May 2011 23:00:00 +0100

Authors: Liu D, He H, Li GL, Chen J, Yin D, Liao ZP, Tang L, Huang QR, Lai ZF, He M During anoxia/reoxygenation (A/R) injury, intracellular chloride ion concentration ([Cl(-)](i)) homeostasis may play a role in maintaining the normal physiological function of cardiomyocytes. Various chloride transport systems could have influenced the concentration of chloride ion, but what kinds of chloride transport systems could play an important role in cardiomyocytes subjected to A/R injury and its mechanism are unknown. The aim of our study was to clarify the contributions of various chloride transport systems to anoxia/reoxygenation in rat neonatal cardiac myocytes and further to investigate the involved mechanisms. Oxidative stress and redox-sensitive transcription factor (NF-kappaB) activation...

MedWorm Sponsor Message: Please support the Doctors In Chains campaign for the medics tortured and sentenced for up to 15 years in Bahrain. #FreeDoctors

Evaluation of the pKa values and ionization sequence of bumetanide using 1H and 13C NMR and UV spectroscopy

Drug Development Research — Sat, 30 Apr 2011 23:00:00 +0100

AbstractNon‐thiazide loop diuretics such as bumetanide and furosemide are well‐established medicaments, with varying substituents that alter their chemical properties in ways that affect biological parameters, including biodistribution, efficacy, and safety. However, literature data supporting the assignment of pKa values and ionization sequence of bumetanide are limited. The present study summarizes available literature data and then characterizes nuclear magnetic resonance (NMR) and ultraviolet (UV) spectral changes over a range of pH values to delineate the apparent sequence of deprotonations. Three macroscopic pKa values, 1.44, 3.74, and 10.37, were determined in water via pH titration experiments monitored by 1H NMR. Both 1H and 13C analyses support assignment of the lowest pKa va...

Tumor Necrosis Factor-alpha is an endogenous inhibitor of Na+-K+-2Cl- cotransporter (NKCC2) isoform A in the thick ascending limb.

American Journal of Physiology. Renal Physiology — Tue, 19 Apr 2011 23:00:00 +0100

Authors: Battula S, Hao S, Pedraza PL, Stier CT, Ferreri NR The effects of TNF gene deletion on renal NKCC2 expression and activity were determined. Outer medulla (OM) from TNF(-/-) mice exhibited a two-fold increase in total NKCC2 protein expression compared with WT mice. This increase was not observed in TNF(-/-) mice treated with recombinant human TNF (hTNF) for 7 days. Administration of hTNF had no effect on total NKCC2 expression in WT mice. A four-fold increase in NKCC2A mRNA accumulation was observed in OM from TNF(-/-) compared with WT mice; NKCC2F and NKCC2B mRNA accumulation was similar between genotypes. The increase in NKCC2A mRNA accumulation was attenuated when TNF(-/-) mice were treated with hTNF. Bumetanide-sensitive O(2) consumption, an in vitro correlate of NKCC2 acti...

Entacapone promotes cAMP‐dependent colonic Cl− secretion in rats

Neurogastroenterology and Motility — Mon, 18 Apr 2011 23:00:00 +0100

Conclusions & Inferences Entacapone stimulates cAMP‐dependent Cl− secretion in the rat colon, and this process is regulated by endogenous PG and the submucosal enteric nervous system. (Source: Neurogastroenterology and Motility)

Volume regulation in mammalian skeletal muscle: The role of sodium-potassium-chloride cotransporters (NKCC) during exposure to hypertonic solutions.

The Journal of Physiology — Sun, 10 Apr 2011 23:00:00 +0100

Authors: Lindinger MI, Leung M, Trajcevski KE, Hawke TJ Controversy exists as to whether mammalian skeletal muscle is capable of volume regulation in response to changes in extracellular osmolarity despite evidence that muscle fibres have the required ion transport mechanisms to transport solute and water in situ. We addressed this issue by studying the ability of skeletal muscle to regulate volume during periods of induced hyperosmotic stress using single, mouse EDL muscle fibres and intact muscle (soleus and EDL). Fibres and intact muscles were loaded with the fluorophore, calcein, and the change in muscle fluorescence and width (single fibres only) used as a metric of volume change. We hypothesized that skeletal muscle exposed to increased extracellular osmolarity would elicit initi...

Ion transport mechanisms linked to bicarbonate secretion in the esophageal submucosal glands.

Tue, 05 Apr 2011 23:00:00 +0100

This study characterized the ion transport mechanisms linked to HCO(3)(-) secretion in SMG. We localized ion transporters using immunofluorescence and we examined their expression by RT-PCR and in situ hybridization. We measured HCO(3)(-) secretion using pH-stat and the isolated perfused esophagus. Using double-labeling with Na,K-ATPase as a marker, we localized Na-coupled bicarbonate transporter (NBCe1) and Cl(-)-HCO(3)(-) exchanger (SLC4A2/AE2) to the basolateral membrane of duct cells. Expression of cystic fibrosis transmembrane regulator channels (CFTR) was confirmed by immunofluorescence, RT-PCR and in situ hybridization. We identified anion exchanger SLC26A6 at the ducts' luminal membrane and Na-K-2Cl (NKCC1) at the basolateral membrane of mucous and duct cells. pH-stat experiments s...

MedWorm Sponsor Message: Find the best January Sales in the UK.

Effects of estradiol on ischemic factor-induced astrocyte swelling and AQP4 protein abundance.

American Journal of Physiology. Cell Physiology — Tue, 05 Apr 2011 23:00:00 +0100

In this study we evaluated the effects of AVP (100 nM), hypoxia (7.5% O(2)), aglycemia, hypoxia (2%)/aglycemia (OGD), and estradiol (1-100 nM) on astrocyte cell volume using 3H-3-0-methyl-D-glucose equilibration methods. We found that AVP, hypoxia, aglycemia and OGD (30 min-5 hr) each significantly increased astrocyte cell volume and that estradiol (30-180 min) abolished swelling induced by AVP or hypoxia but not by aglycemia or OGD. Bumetanide and/or HOE-642 also abolished swelling induced by AVP but not aglycemia. Abundance of aquaporin 4 (AQP4), known to participate in ischemia-induced astrocyte swelling, was significantly reduced following 7-day but not 2-3 hr estradiol exposures. Our findings suggest that hypoxia, aglycemia and AVP each contribute to ischemia-induced astrocyte swellin...

Differential regulation of NFAT5 by NKCC2 isoforms in medullary thick ascending limb (mTAL) cells

AJP: Renal Physiology — Sun, 03 Apr 2011 23:00:00 +0100

The effects of Na+-K+-2Cl– cotransporter type 2 (NKCC2) isoforms on the regulation of nuclear factor of activated T cells isoform 5 (NFAT5) were determined in mouse medullary thick ascending limb (mTAL) cells exposed to high NaCl concentration. Primary cultures of mTAL cells and freshly isolated mTAL tubules, both derived from the outer medulla (outer stripe>inner stripe), express NKCC2 isoforms A and F. The relative expression of NKCC2A mRNA was approximately twofold greater than NKCC2F in these preparations. The abundance of NKCC2A mRNA, but not NKCC2F mRNA, increased approximately twofold when mTAL cells were exposed for 2 h to a change in osmolality from 300 to 500 mosmol/kgH2O, produced with NaCl. Total NKCC2 protein expression also increased. Moreover, a 2.5-fold increase in...

Neuronal chloride accumulation and excitatory GABA underlie aggravation of neonatal epileptiform activities by phenobarbital

Brain — Thu, 31 Mar 2011 23:00:00 +0100

Phenobarbital produces its anti-epileptic actions by increasing the inhibitory drive of -aminobutyric acid. However, following recurrent seizures, -aminobutyric acid excites neurons because of a persistent increase of chloride raising the important issue of whether phenobarbital could aggravate persistent seizures. Here we compared the actions of phenobarbital on initial and established ictal-like events in an in vitro model of mirror focus. Using the in vitro three-compartment chamber preparation with the two hippocampi and their commissural fibres placed in three different chambers, kainate was applied to one hippocampus and phenobarbital contralaterally, either after one ictal-like event or after many recurrent ictal-like events that produce an epileptogenic mirror focus. Field, perfora...

Functional plasticity of mitochondrion-rich cells in the skin of euryhaline medaka larvae (Oryzias latipes) subjected to salinity changes

AJP: Regulatory, Integrative and Comparative Physiology — Thu, 31 Mar 2011 23:00:00 +0100

This study provides evidence demonstrating that ACs are required for Na+ excretion and MRCs possess a functional plasticity in changing from a Na+/Cl–-secreting cell to a Na+/Cl–-absorbing cell. (Source: AJP: Regulatory, Integrative and Comparative Physiology)

Large-scale phosphoproteomic analysis of membrane proteins in renal proximal and distal tubule

AJP: Cell Physiology — Sun, 27 Mar 2011 23:00:00 +0100

Recent advances in mass spectrometry (MS) have provided means for large-scale phosphoproteomic profiling of specific tissues. Here, we report results from large-scale tandem MS [liquid chromatography (LC)-MS/MS]-based phosphoproteomic profiling of biochemically isolated membranes from the renal cortex, with focus on transporters and regulatory proteins. Data sets were filtered (by target-decoy analysis) to limit false-positive identifications to <2%. A total of 7,125 unique nonphosphorylated and 743 unique phosphorylated peptides were identified. Among the phosphopeptides identified were sites on transporter proteins, i.e., solute carrier (Slc, n = 63), ATP-binding cassette (Abc, n = 4), and aquaporin (Aqp, n = 3) family proteins. Database searches reveal that a majority of the phosphor...

MedWorm Sponsor Message: Please support the Doctors In Chains campaign for the medics tortured and sentenced for up to 15 years in Bahrain. #FreeDoctors

Different effects of α-chloralose on spontaneous and evoked GABA release in rat hippocampal CA1 neurons.

Brain Research Bulletin — Sun, 27 Mar 2011 23:00:00 +0100

Authors: Matsuura T, Iwata S, Shin MC, Wakita M, Ogawa SK, Akaike N The effects of α-chloralose on presynaptic GABA(A) receptors were investigated with respect to spontaneous and evoked GABAergic transmission (sIPSCs and eIPSCs) in rat hippocampal CA1 pyramidal neurons. sIPSCs were recorded in mechanically dissociated CA1 neurons with intact GABAergic terminals, namely the "synaptic bouton preparation." eIPSCs were elicited by focal electrical stimuli of a single GABAergic bouton on an isolated CA1 neuron using the whole-cell patch recording configurations under voltage-clamp condition. We found that α-chloralose potentiated the exogenous GABA-induced Cl(-) response in a concentration dependent manner, and the drug itself induced Cl(-) response at high concentrations (> 100μM). �...

Renal sodium transporter/channel expression and sodium excretion in P2Y2 receptor knockout mice fed a high-NaCl diet with/without aldosterone infusion

AJP: Renal Physiology — Mon, 07 Mar 2011 00:00:00 +0100

The P2Y2 receptor (P2Y2-R) antagonizes sodium reabsorption in the kidney. Apart from its effect in distal nephron, hypothetically, P2Y2-R may modulate activity/abundances of sodium transporters/channel subunits along the nephron via antagonism of aldosterone or vasopressin or interaction with mediators such as nitric oxide (NO), and prostaglandin E2 (PGE2) or oxidative stress (OS). To determine the extent of the regulatory role of P2Y2-R in renal sodium reabsorption, in study 1, we fed P2Y2-R knockout (KO; n = 5) and wild-type (WT; n = 5) mice a high (3.15%)-sodium diet (HSD) for 14 days. Western blotting revealed significantly higher protein abundances for cortical and medullary bumetanide-sensitive Na-K-2Cl cotransporter (NKCC2), medullary α-1-subunit of Na-K-ATPase, and medullary ...

Properties of substance P-stimulated mucus secretion from porcine tracheal submucosal glands

AJP: Lung Cellular and Molecular Physiology — Wed, 02 Mar 2011 00:00:00 +0100

Human and pig airway submucosal glands secrete mucus in response to substance P (SubP), but in pig tracheal glands the response to SubP is >10-fold greater than in humans and shares features with cholinergically produced secretion. CFTR-deficient pigs provide a model for human cystic fibrosis (CF), and in newborn CF pigs the response of tracheal glands to SubP is significantly reduced (Joo et al. J Clin Invest 120: 3161–3166, 2010). To further define features of SubP-mediated gland secretion, we optically measured secretion rates from individual adult porcine glands in isolated tracheal tissues in response to mucosal capsaicin and serosal SubP. Mucosal capsaicin (EC50 = 19 µM) stimulated low rates of secretion that were partially inhibited by tetrodotoxin and by inhibitors f...

Two-photon microscopy and fluorescence lifetime imaging reveal stimulus-induced intracellular Na+ and Cl- changes in cockroach salivary acinar cells.

American Journal of Physiology. Cell Physiology — Wed, 23 Feb 2011 00:00:00 +0100

Authors: Lahn M, Dosche C, Hille C The intracellular ion homeostasis in cockroach salivary acinar cells during salivation is not satisfactorily understood. This is mainly due to technical problems regarding strong tissue autofluorescence and ineffective ion concentration quantification. For minimizing these problems, we describe the successful application of two-photon (2P)-microscopy partly in combination with fluorescence lifetime imaging microscopy (FLIM) in order to record intracellular Na(+) and Cl(-) concentrations ([Na(+)](i), [Cl(-)](i)) in cockroach salivary acinar cells. Quantitative 2P-FLIM Cl(-)-measurements with the dye MQAE indicate that the resting [Cl(-)](i) is 1.6 times above the Cl(-) electrochemical equilibrium, but is not influenced by pharmacological inhibition of ...

Blocking Early GABA Depolarization with Bumetanide Results in Permanent Alterations in Cortical Circuits and Sensorimotor Gating Deficits

Cerebral Cortex — Fri, 18 Feb 2011 00:00:00 +0100

A high incidence of seizures occurs during the neonatal period when immature networks are hyperexcitable and susceptible to hypersyncrhonous activity. During development, -aminobutyric acid (GABA), the primary inhibitory neurotransmitter in adults, typically excites neurons due to high expression of the Na+-K+-2Cl– cotransporter (NKCC1). NKCC1 facilitates seizures because it renders GABA activity excitatory through intracellular Cl– accumulation, while blocking NKCC1 with bumetanide suppresses seizures. Bumetanide is currently being tested in clinical trials for treatment of neonatal seizures. By blocking NKCC1 with bumetanide during cortical development, we found a critical period for the development of α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate synapses. Disrupt...

MedWorm Sponsor Message: Find the best January Sales in the UK.

Na‐K‐Cl Cotransporter‐1 in the Mechanism of Cell Swelling in Cultured Astrocytes After Fluid Percussion Injury

Journal of Neurochemistry — Wed, 09 Feb 2011 18:18:07 +0100

AbstractBrain edema and associated increased intracranial pressure are major consequences of traumatic brain injury (TBI). An important early component of the edema associated with TBI is astrocyte swelling (cytotoxic edema). Mechanisms for such swelling, however, are poorly understood. Ion channels/transporters/exchangers play a major role in cell volume regulation, and a disturbance in one or more of these systems may result in cell swelling. To examine potential mechanisms in TBI‐mediated brain edema, we employed a fluid percussion model of in vitro barotrauma and examined the role of the ion transporter Na+‐K+‐2Cl‐‐cotransporter (NKCC1) in trauma‐induced astrocyte swelling as this transporter has been strongly implicated in the mechanism of cell swelling in various neurolog...

Updated national IV monograph on Bumetanide

NeLM - News — Wed, 09 Feb 2011 00:00:00 +0100

Effects of carbon monoxide on ion transport across rat distal colon

AJP: Gastrointestinal and Liver Physiology — Fri, 28 Jan 2011 00:00:00 +0100

The aim of the present study was to investigate whether carbon monoxide (CO) induces changes in ion transport across the distal colon of rats and to study the mechanisms involved. In Ussing chamber experiments, tricarbonyldichlororuthenium(II) dimer (CORM-2), a CO donor, evoked a concentration-dependent increase in short-circuit current (Isc). A maximal response was achieved at a concentration of 2.5·10–4 mol/l. Repeated application of CORM-2 resulted in a pronounced desensitization of the tissue. Anion substitution experiments suggest that a secretion of Cl– and HCO3– underlie the CORM-2-induced current. Glibenclamide, a blocker of the apical cystic fibrosis transmembrane regulator channel, inhibited the Isc induced by the CO donor. Similarly, bumetanide, a blocke...

Mechanisms of chloride uptake in frog olfactory receptor neurons

Fri, 21 Jan 2011 15:06:08 +0100

Abstract Odorant stimulation of olfactory receptor neurons (ORNs) leads to the activation of a Ca2+ permeable cyclic nucleotide-gated (CNG) channel followed by opening of an excitatory Ca2+-activated Cl− channel, which carries about 70% of the odorant-induced receptor current. This requires ORNs to have a [Cl−]i above the electrochemical equilibrium to render this anionic current excitatory. In mammalian ORNs, the Na+-K+-2Cl− co-transporter 1 (NKCC1) has been characterized as the principal mechanism by which these neurons actively accumulate Cl−. To determine if NKCC activity is needed in amphibian olfactory transduction, and to characterize its cellular location, we used the suction pipette technique to record from Rana pipiens ORNs. Application of bumetanide, an NKCC ...

MedWorm Sponsor Message: Please support the Doctors In Chains campaign for the medics tortured and sentenced for up to 15 years in Bahrain. #FreeDoctors

Hospital Pharmacists Scrambling Amid Vast Drug Shortages: Emergency Physicians Between Roc and a Hard Place

Annals of Emergency Medicine — Wed, 19 Jan 2011 15:44:13 +0100

On the Web site of the American Society of Health System Pharmacists (ASHP), the list goes on for pages: atracurium, bumetanide, buprenorphine, clindamycin, cisatracurium, epinephrine, fentanyl, furosemide, lipid emulsion, lidocaine, metronidazole, naloxone, propofol, rocuronium, succinylcholine, sulfamethoxazole-trimethoprim, torsemide, vancomycin hydrochloride, vecuronium. They are all sterile injectable drugs that an emergency physician might use every day, and they and dozens of other drugs—more than 140 in late November—are on the list because they are either unavailable or in extremely short supply. There is a similar though less complete list, bearing 50 names in late November, on the Web site of the Food and Drug Administration (FDA). (Source: Annals of Emergency Medicine)

In isolated skeletal muscle, excitation may increase extracellular K+ 10‐fold; how can contractility be maintained?

Experimental Physiology — Wed, 19 Jan 2011 00:00:00 +0100

In conclusion, during repeated excitation, isolated rat muscles undergo a much greater increase in [K+]o than previously reported, sufficient to explain loss of force. This K+ is not cleared via Na+–K+–2Cl– cotransport, but rather via Na+–K+ pumps and by processes depending on Cl− exchange. These mechanisms are essential for the maintenance of force during intense contractions in vivo, where the clearance of K+ via the capillaries may be suppressed. (Source: Experimental Physiology)

Differential regulation of NFAT5 by NKCC2 isoforms in medullary thick ascending limb (mTAL) cells.

American Journal of Physiology. Renal Physiology — Wed, 12 Jan 2011 00:00:00 +0100

Authors: Hao S, Zhao H, Darzynkiewicz Z, Battula S, Ferreri NR The effects of Na(+)-K(+)-2Cl- cotransporter type 2 (NKCC2) isoforms on the regulation of nuclear factor of activated T cells isoform 5 (NFAT5) was determined in mouse medullary thick ascending limb (mTAL) cells exposed to high NaCl concentration. Primary cultures of mTAL cells and freshly isolated mTAL tubules, both derived from outer medulla (outer stripe>inner stripe), express NKCC2 isoforms A and F. The relative expression of NKCC2A mRNA was approximately two-fold greater than NKCC2F in these preparations. The abundance of NKCC2A mRNA, but not NKCC2F mRNA, increased approximately two-fold when mTAL cells were exposed for 2 hr to a change in osmolality from 300 to 500 mosmol/kg H(2)O, produced with NaCl. Total NKCC2 p...

Swelling activated Cl- channels in microglia: Biophysics, pharmacology and role in glutamate release.

Channels — Fri, 07 Jan 2011 12:47:09 +0100

Authors: Schlichter LC, Mertens T, Liu B Microglia have a swelling-activated Cl- current (which we call IClswell), and while some of its biophysical properties and functional roles have been elucidated, its molecular identity is unknown. To relate this current to cell functions and determine whether it is regulated by mechanisms other than cell swelling, it is important to establish both biophysical and pharmacological fingerprints. Here, we used rat microglia and a cell line derived from them (MLS-9) to study biophysical, regulatory and pharmacological properties of IClswell. The whole-cell current was activated in response to a hypo-osmotic bath solution, but not by voltage, and was time-independent during long voltage steps. The halide selectivity sequence was I->Br->Cl- (Eise...

Large-Scale Phosphoproteomic Analysis of Membrane Proteins in Renal Proximal and Distal Tubule.

American Journal of Physiology. Cell Physiology — Wed, 05 Jan 2011 00:00:00 +0100

Authors: Feric M, Zhao B, Hoffert JD, Pisitkun T, Knepper MA Recent advances in mass spectrometry have provided means for large-scale phosphoproteomic profiling of specific tissues. Here, we report results from large-scale LC-MS/MS-based phosphoproteomic profiling of biochemically isolated membranes from the renal cortex, focusing on transporters and regulatory proteins. Data sets were filtered (target-decoy) to limit false-positive identifications to <2%. A total of 7,125 unique non-phosphorylated and 743 unique phosphorylated peptides were identified. The phosphopeptides that were found included sites on transporter proteins, i.e. in Slc (n=63), Abc (n=4), and Aqp (n=3) family proteins. A majority of the phosphorylation sites identified in transporter proteins were previously unre...

MedWorm Sponsor Message: Find the best January Sales in the UK.

Components of neuronal chloride transport in rat and human neocortex.

The Journal of Physiology — Tue, 04 Jan 2011 00:00:00 +0100

Authors: Deisz RA, Lehmann TN, Horn P, Dehnicke C, Nitsch R Considerable evidence indicates disturbances in the ionic gradient of GABA(A) receptor-mediated inhibition of neurones in human epileptogenic tissues. Two contending mechanisms have been proposed, reduced outward or increased inward Cl(-) transporters. We investigated the properties of Cl(-) transport in human and rat neocortical neurones (layer II/III) using intracellular recordings in slices of cortical tissue.We measured the alterations in reversal potential of pharmacologically isolated IPSP(A) to estimate the ionic gradient and kinetics of Cl(-) efflux after Cl(-) injections before and during the application of selected blockers of Cl(-) routes (furosemide, bumetanide, 9AC and Cs(+)). Neurones from human epileptogenic cor...

Combined effect of bumetanide, bromide, and GABAergic agonists: An alternative treatment for intractable seizures.

Epilepsy and Behaviour — Sat, 01 Jan 2011 00:00:00 +0100

Authors: Almeida AC, Scorza FA, Rodrigues AM, Arida RM, Carlesso FN, Batista AG, Duarte MA, Dacosta JC PMID: 21167788 [PubMed - in process] (Source: Epilepsy and Behaviour)

Functional Plasticity of Mitochondrion-Rich Cells in the Skin of Euryhaline Medaka Larvae (Oryzias latipes) Subjected to Salinity Changes.

Wed, 29 Dec 2010 00:00:00 +0100

This study provides evidence demonstrating that ACs are required for Na(+) excretion and MRCs possess a function plasticity in changing from a Na(+)/Cl(-)-secreting cell to a Na(+)/Cl(-)-absorbing cell. PMID: 21191003 [PubMed - as supplied by publisher] (Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology)

Renal Sodium Transporter/Channel Expression and Sodium Excretion in P2Y2 Receptor Knockout Mice fed High NaCl Diet with/without Aldosterone Infusion.

American Journal of Physiology. Renal Physiology — Wed, 29 Dec 2010 00:00:00 +0100

Authors: Zhang Y, Listhrop R, Ecelbarger CM, Kishore BK P2Y(2) receptor (P2Y2-R) antagonizes sodium reabsorption in the kidney. Apart from its effect in distal nephron, hypothetically, P2Y(2)-R may modulate activity/abundances of sodium transporters/channel subunits along the nephron via antagonism of aldosterone or vasopressin or interaction with mediators such as nitric oxide (NO) or prostaglandin E(2) (PGE(2)) or oxidative stress (OS). To determine the extent of the regulatory role of P2Y2-R in renal sodium reabsorption, in Study 1, we fed P2Y(2)-R knockout (KO; n = 5) and wild-type (WT; n = 5) mice high (3.15%) sodium diet (HSD) for 14 days. Western blotting revealed significantly higher protein abundances for cortical and medullary bumetanide-sensitive Na-K-2Cl cotransporter (NKCC...

Lubiprostone Reverses the Inhibitory Action of Morphine on Mucosal Secretion in Human Small Intestine

Digestive Diseases and Sciences — Wed, 22 Dec 2010 20:19:40 +0100

Conclusions Antisecretory action of morphine results from suppression of excitability of secretomotor neurons in the enteric nervous system. Lubiprostone, which does not affect enteric neurons directly, bypasses the action of morphine by directly opening mucosal chloride channels. Content Type Journal ArticleDOI 10.1007/s10620-010-1515-8Authors Xiaohong Sun, Department of Physiology and Cell Biology, The Ohio State University College of Medicine, 304 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210, USAXiyu Wang, Department of Anesthesiology, The Ohio State University College of Medicine, Columbus, OH USAGuo-Du Wang, Department of Physiology and Cell Biology, The Ohio State University College of Medicine, 304 Hamilton Hall, 1645 Neil Avenue, Columbus, OH 43210, U...

MedWorm Sponsor Message: Please support the Doctors In Chains campaign for the medics tortured and sentenced for up to 15 years in Bahrain. #FreeDoctors

Lubiprostone Activates Cl− Secretion via cAMP Signaling and Increases Membrane CFTR in the Human Colon Carcinoma Cell Line, T84

Digestive Diseases and Sciences — Tue, 07 Dec 2010 13:47:26 +0100

Conclusions Lubiprostone activates Cl− secretion in T84 cells via cAMP, protein kinase A, and by increasing apical membrane CFTR protein. Content Type Journal ArticlePages 1-13DOI 10.1007/s10620-010-1495-8Authors Mei Ao, Department of Physiology and Biophysics, University of Illinois at Chicago, 835 S. Wolcott Ave. M/C 901, Chicago, IL 60612, USAJayashree Venkatasubramanian, Department of Physiology and Biophysics, University of Illinois at Chicago, 835 S. Wolcott Ave. M/C 901, Chicago, IL 60612, USAChaiwat Boonkaewwan, Department of Physiology and Biophysics, University of Illinois at Chicago, 835 S. Wolcott Ave. M/C 901, Chicago, IL 60612, USANivetha Ganesan, Department of Physiology and Biophysics, University of Illinois at Chicago, 835 S. Wolcott Ave. M/C 901, C...

Non-neuronal release of ACh plays a key role in secretory response to luminal propionate in rat colon.

The Journal of Physiology — Mon, 06 Dec 2010 00:00:00 +0100

In conclusion, the non-neuronal release of ACh from colonocytes coupled with propionate stimulation plays a key role in chloride secretion, via the paracrine action of ACh on muscarinic receptors of colonocytes. PMID: 21135046 [PubMed - as supplied by publisher] (Source: The Journal of Physiology)

Properties of Substance P-stimulated Mucus Secretion from Porcine Tracheal Submucosal Glands.

Am J Physiol Lung Ce... — Fri, 03 Dec 2010 00:00:00 +0100

Authors: Khansaheb M, Choi JY, Joo NS, Yang YM, Krouse M, Wine JJ Human and pig airway submucosal glands secrete mucus in response to Substance P (SubP), but in pig tracheal glands the response to SubP is more than 10-fold greater than in humans and shares features with cholinergically produced secretion. CFTR-deficient pigs provide a model for human CF disease, and in newborn CF pigs the response of tracheal glands to SubP is significantly reduced, (Joo et al., JCI, 2010). To further define features of SubP-mediated gland secretion, we optically measured secretion rates from individual adult porcine glands in isolated tracheal tissues in response to mucosal capsaicin and serosal SubP. Mucosal capsaicin (EC(50) 19 μM) stimulated low rates of secretion that were partially inhibited by ...

Astrocyte ERK phosphorylation precedes K+‐induced swelling but follows hypotonicity‐induced swelling

Neuropathology — Wed, 01 Dec 2010 00:00:00 +0100

Hypotonicity following water intoxication and/or salt loss leads to mainly astrocytic brain swelling. Astrocytic swelling also occurs following brain trauma or ischemia, together with an increase in extracellular K+ ([K+]o), stimulating a bumetanide/furosemide/ethacrynic acid‐inhibitable cotransporter, NKCC1, that accumulates Na+ and K+ together with 2 Cl‐ and osmotically obliged water. Either type of swelling may become fatal and is associated with phosphorylation of extracellular regulated kinases 1 and 2 (ERK1/2). Only the swelling associated with elevated [K+]o, leads to an increase in astrocytic proliferation and in expression of the astrocytic marker, glial fibrillary acidic protein. These differences prompted us to investigate key aspects of the molecular pathways between hypoto...

Effects of carbon monoxide on ion transport across rat distal colon.

American Journal of Physiology. Gastrointestinal and Liver Physiology — Thu, 18 Nov 2010 00:00:00 +0100

Authors: Steidle J, Diener M The aim of the present study was to investigate whether carbon monoxide induces changes in ion transport across rat distal colon and to study the mechanisms involved. In Ussing chamber experiments, tricarbonyldichlororuthenium(II) dimer (RuCO), a CO donor, evoked a concentration-dependent increase in short-circuit current (I(sc)). A maximal response was achieved at a concentration of 2.5⋅10(-4) mol⋅l(-1). Repeated application of RuCO resulted in a pronounced desensitization of the tissue. Anion substitution experiments suggest that a secretion of Cl(-) and HCO(3)(-) underlie the RuCO-induced current. Glibenclamide, a blocker of the apical CFTR channel, inhibited the I(sc) induced by the CO donor. Similarly, bumetanide, a blocker of the basolateral Na(+)...

MedWorm Sponsor Message: Find the best January Sales in the UK.

Cystic fibrosis transmembrane conductance regulator modulates synaptic chloride homeostasis in motoneurons of the rat spinal cord during neonatal development

Journal of Neurobiology — Tue, 09 Nov 2010 00:00:00 +0100

AbstractCystic Fibrosis Transmembrane Conductance Regulator (CFTR) is a cAMP‐regulated Cl− channel functional in neonatal rat spinal motoneurons. The present study investigated the developmental (P1‐P8) expression of CFTR, its impact on motoneuron excitability and Cl− homeostasis in relation to canonical Cl− transporters. The Cl− outward transporter KCC2 gene was upregulated in females over males and increased from P1 to P8. The gene activities of the Cl− inward transporter NKCC1 and CFTR were positively correlated and grew between P1 and P8. P1 motoneuronal somata were immunopositive for CFTR whose expression later (P8) extended to cell processes. KCC2 immunopositivity outlined somata and cell processes at P1 and P8. Electrophysiological recording with sharp electrodes showe...

Increased renal {alpha}-epithelial sodium channel (ENAC) protein and increased ENAC activity in normal pregnancy

AJP: Regulatory, Integrative and Comparative Physiology — Tue, 02 Nov 2010 00:00:00 +0100

Pregnancy-mediated sodium (Na) retention is required to provide an increase in plasma volume for the growing fetus. The mechanisms responsible for this Na retention are not clear. We first used a targeted proteomics approach and found that there were no changes in the protein abundance compared with virgin rats of the β or ENaC, type 3 Na+/H+ exchanger (NHE3), bumetanide-sensitive cotransporter (NKCC2), or NaCl cotransporter (NCC) in mid- or late pregnancy. In contrast, we observed marked increases in the abundance of the -ENaC subunit. The plasma volume increased progressively during pregnancy with the greatest plasma volume being evident in late pregnancy. ENaC inhibition abolished the difference in plasma volume status between virgin and pregnant rats. To determine the in vivo acti...

Renal Efflux Transporter for Drugs and Urate [Molecular Bases Of Disease]

Journal of Biological Chemistry — Thu, 28 Oct 2010 23:00:00 +0100

In this report, we demonstrate that an orphan transporter hNPT4 (human sodium phosphate transporter 4; SLC17A3) was a multispecific organic anion efflux transporter expressed in the kidneys and liver. hNPT4 was localized at the apical side of renal tubules and functioned as a voltage-driven urate transporter. Furthermore, loop diuretics, such as furosemide and bumetanide, substantially interacted with hNPT4. Thus, this protein is likely to act as a common secretion route for both drugs and may play an important role in diuretics-induced hyperuricemia. The in vivo role of hNPT4 was suggested by two hyperuricemia patients with missense mutations in SLC17A3. These mutated versions of hNPT4 exhibited reduced urate efflux when they were expressed in Xenopus oocytes. Our findings will complete a...

GABA(A) receptor-mediated presynaptic inhibition on glutamatergic transmission.

Brain Research Bulletin — Thu, 28 Oct 2010 00:00:00 +0100

Authors: Yamamoto S, Yoshimura M, Shin MC, Wakita M, Nonaka K, Akaike N We investigated the functional roles of presynaptic GABA(A) receptors on excitatory nerve terminals in contributing to spontaneous and action potential-evoked glutamatergic transmission to rat hippocampal CA3 pyramidal neurons. Single CA3 neurons were mechanically isolated with adherent nerve terminals, namely the 'synaptic bouton preparation', and spontaneous glutamatergic excitatory synaptic potentials (sEPSCs) and EPSCs evoked by focal electrical stimuli of a single presynaptic glutamatergic boutons (eEPSCs) were recorded using conventional whole-cell patch recordings. Selective activation of presynaptic GABA(A) receptors on these excitatory nerve terminals by muscimol, markedly facilitated sEPSCs frequency but ...

The Na–K–Cl cotransporter in the brain edema of acute liver failure

Journal of Hepatology — Thu, 21 Oct 2010 00:00:00 +0100

Conclusions: Our studies suggest the involvement of NKCC in the development of brain edema in experimental ALF, and that targeting NKCC may represent a useful therapeutic strategy in humans with ALF. (Source: Journal of Hepatology)

MedWorm Sponsor Message: Please support the Doctors In Chains campaign for the medics tortured and sentenced for up to 15 years in Bahrain. #FreeDoctors

Role of the NKCC1 co-transporter in sensitization of spinal nociceptive neurons

Pain — Fri, 08 Oct 2010 00:00:00 +0100

Abstract: The Na+, K+, 2Cl− co-transporter type 1 (NKCC1) plays a pivotal role in hyperalgesia associated with inflammatory stimuli. NKCC1 contributes to maintain high [Cl−]i in dorsal root ganglia (DRG) neurons which cause primary afferent depolarization (PAD) when GABAA receptors are activated. Enhanced GABA-induced depolarization, through increased NKCC1 activity, has been hypothesized to produce orthodromic spike activity of sufficient intensity to account for touch-induced pain. In the present study, we investigate this hypothesis using in vivo electrophysiology on rat dorsal horn neurons; the effects of spinal blockade of NKCC1 on intraplantar capsaicin-induced sensitization of dorsal horn neurons were examined. Single wide dynamic range (WDR) and nociceptive specific (NS) neuron...

Cell volume regulation following hypotonic shock in hepatocytes isolated from Sparus aurata.

Thu, 07 Oct 2010 23:00:00 +0100

Authors: Faggio C, Torre A, Pelle E, Raffa F, Villari V, Trischitta F The response of isolated hepatocytes of Sparus aurata to hypotonic shock was studied by the aid of videometric and light scattering methods. The isolated cells exposed to a rapid change (from 370 to 260mOsm/kg) of the osmolarity of the bathing solution swelled but thereafter underwent a decrease of cell volume tending to recovery the original size. This homeostatic response RVD (Regulatory Volume Decrease) was inhibited in the absence of extracellular Ca(2+) and in the presence of TMB8, an inhibitor of Ca(2+) release from intracellular stores. It is likely that Ca(2+) entry through verapamil sensitive Ca(2+)- channels, probably leading to a release of Ca(2+) from intracellular stores, is responsible for RVD since the...

Cotransport of water by the Na+-K+-2Cl- cotransporter NKCC1 in mammalian epithelial cells.

The Journal of Physiology — Sun, 05 Sep 2010 23:00:00 +0100

Authors: Hamann S, Herrera-Perez JJ, Zeuthen T, Alvarez-Leefmans FJ Water transport by the Na(+)-K(+)-2Cl(-) cotransporter (NKCC1) was studied in confluent cultures of pigmented epithelial (PE) cells from the ciliary body of the fetal human eye. Interdependence among water, Na(+), and Cl(-) fluxes mediated by NKCC1 was inferred from changes in cell water volume, monitored by intracellular self-quenching of the fluorescent dye calcein. Isosmotic removal of external Cl(-) or Na(+) caused a rapid efflux of water from the cells that were inhibited by bumetanide (10 microM). When returned to the control solution there was a rapid water influx that required the simultaneous presence of external Na(+) and Cl(-). The water influx could proceed uphill, against a transmembrane osmotic gradient, ...

Age‐ and region‐specific effects of anticonvulsants and bumetanide on 4‐aminopyridine–induced seizure‐like events in immature rat hippocampal–entorhinal cortex slices

Epilepsia — Tue, 31 Aug 2010 23:00:00 +0100

Summary (Source: Epilepsia)

Insulin Induces Swelling-dependent Activation of the Epidermal Growth Factor Receptor in Rat Liver [Cell Biology]

Journal of Biological Chemistry — Fri, 13 Aug 2010 13:41:47 +0100

The aim of the study was to analyze whether the proliferative effects of insulin in rat liver involve cross-signaling toward the epidermal growth factor receptor (EGFR) and whether this is mediated by insulin-induced hepatocyte swelling. Studies were performed in the perfused rat liver and in primary rat hepatocytes. Insulin (35 nmol/liter) induced phosphorylation of the EGFR at position Tyr845 and Tyr1173, but not at Tyr1045, suggesting that EGF is not involved in insulin-induced EGFR activation. Insulin-induced EGFR phosphorylation and subsequent ERK1/2 phosphorylation were sensitive to bumetanide, indicating an involvement of insulin-induced hepatocyte swelling. In line with this, hypoosmotic (225 mosmol/liter) hepatocyte swelling also induced EGFR and ERK1/2 activation. Insulin- and hy...

MedWorm Sponsor Message: Find the best January Sales in the UK.

Insulin and EGFR Activation [Cell Biology]

Journal of Biological Chemistry — Fri, 13 Aug 2010 13:41:47 +0100

Increased Renal {alpha} Epithelial Sodium Channel (ENaC) Protein and Increased ENaC Activity in Normal Pregnancy.

Tue, 03 Aug 2010 23:00:00 +0100

Authors: West CA, Zhang Z, Ecker G, Masilamani SM Pregnancy-mediated sodium (Na) retention is required to provide an increase in plasma volume for the growing fetus. The mechanisms responsible for this Na retention are not clear. We first used a targeted proteomics approach and found that there were no changes in the protein abundance compared to virgin rats of the beta or gamma ENaC, type 3 Na/H exchanger (NHE3), bumetanide-sensitive cotransporter (NKCC2) or NaCl cotransporter (NCC) in mid- or late- pregnancy. In contrast, we observed marked increases in the abundance of the alpha ENaC subunit. The plasma volume increased progressively during pregnancy with the greatest plasma volume being evident in late pregnancy. ENaC inhibition abolished the difference in plasma volume status betw...

REGULAR ARTICLE: The diuretic bumetanide decreases autistic behaviour in five infants treated during 3 months with no side effects

Acta Paediatrica — Sat, 31 Jul 2010 23:00:00 +0100

(Source: Acta Paediatrica)

Sodium–bicarbonate cotransporter NBCn1 in the kidney medullary thick ascending limb cell line is upregulated under acidic conditions and enhances ammonium transport

Experimental Physiology — Sat, 17 Jul 2010 23:00:00 +0100

In this study, we examined the effect of bicarbonate transporters on ammonium/ammonia uptake in the medullary thick ascending limb cell line ST-1. Cells were treated with 1 mm ouabain and 0.2 mm bumetanide to minimize carrier-mediated NH4+ transport, and the intracellular accumulation of 14C-methylammonium/methylammonia (14C-MA) was determined. In CO2/HCO3[minus]-free solution, cells at normal pH briefly accumulated 14C-MA over 7 min and reached a plateau. In CO2/HCO3[minus] solution, however, cells markedly accumulated 14C-MA over the experimental period of 30 min. This CO2/HCO3[minus]-dependent accumulation was reduced by the bicarbonate transporter blocker, 4,4'-diisothiocyanatostilbene-2,2'-disulfonate (DIDS; 0.5 mm). Replacing Cl[minus] with gluconate reduced the accumulation, but the...

Endoplasmic reticulum Ca2+ signaling and mitochondrial Cyt c release in astrocytes following oxygen and glucose deprivation

Journal of Neurochemistry — Thu, 15 Jul 2010 23:00:00 +0100

J. Neurochem. (2010) 10.1111/j.1471-4159.2010.06862.x In the present study, we investigated changes of cytosolic Ca2+([Ca2+]cyt), endoplasmic reticulum Ca2+([Ca2+]ER) and mitochondrial Ca2+(Ca2+m) in astrocytes following oxygen/glucose deprivation and reoxygenation (OGD/REOX). Two hours OGD did not cause changes in [Ca2+]cyt, but led to a significant increase in [Ca2+]ER. The elevation in [Ca2+]ER continued and reached a peak level (130 ± 2 [mu]M) by 90 min REOX. An abrupt release of Ca2+ER occurred during 1.5[ndash]2.5 h REOX, which was accompanied with a delayed and sustained rise in [Ca2+]cyt. Moreover, Ca2+m content was increased significantly within 15 min REOX followed by a secondary rise ([sim]4.5-fold) and a release of mitochondrial cytochrome c (Cyt c). Astrocytes exhibited trans...

MedWorm Sponsor Message: Please support the Doctors In Chains campaign for the medics tortured and sentenced for up to 15 years in Bahrain. #FreeDoctors

The diuretic bumetanide decreases autistic behaviour in 5 infants treated during 3 months with no side effects

Acta Paediatrica — Wed, 30 Jun 2010 23:00:00 +0100

(Source: Acta Paediatrica)

Modulation of NaCl absorption by [HCOFormula] in the marine teleost intestine is mediated by soluble adenylyl cyclase

AJP: Regulatory, Integrative and Comparative Physiology — Thu, 24 Jun 2010 21:06:56 +0100

Intestinal HCO3– secretion and NaCl absorption are essential for counteracting dehydration in marine teleost fish. We investigated how these two processes are coordinated in toadfish. HCO3– stimulated a luminal positive short-circuit current (Isc) in intestine mounted in Ussing chamber, bathed with the same saline solution on the external and internal sides of the epithelium. The Isc increased proportionally to the [HCO3–] in the bath up to 80 mM NaHCO3, and it did not occur when NaHCO3 was replaced with Na+-gluconate or with NaHCO3 in Cl–-free saline. HCO3– (20 mM) induced a ~2.5-fold stimulation of Isc, and this [HCO3–] was used in all subsequent experiments. The HCO3–-stimulated Isc was prevented or abolished by apical application of 10 µM...

Basolateral Cl- uptake mechanisms in Xenopus laevis lung epithelium

AJP: Regulatory, Integrative and Comparative Physiology — Thu, 24 Jun 2010 21:06:56 +0100

This study focuses on basolateral Cl– uptake mechanisms in native lungs of Xenopus laevis and the involvement of the Na+/K+/2 Cl– cotransporter (NKCC) and HCO3–/Cl– anion exchanger (AE), in particular. Western blot analysis and immunofluorescence staining revealed the expression of the NKCC protein in the Xenopus lung. Ussing chamber experiments demonstrated that the NKCC inhibitors (bumetanide and furosemide) were ineffective at blocking the cotransporter under basal conditions, as well as under pharmacologically stimulated Cl–-secreting conditions (forskolin and chlorzoxazone application). However, functional evidence for the NKCC was detected by generating a transepithelial Cl– gradient. Further, we were interested in the involvement of the HCO3&ndash...

Inhibition of the Sodium-Potassium-Chloride Cotransporter Isoform-1 Reduces Glioma Invasion.

Cell Research — Mon, 21 Jun 2010 23:00:00 +0100

Authors: Haas BR, Sontheimer H Malignant gliomas metastasize throughout the brain by infiltrative cell migration into peritumoral areas. Invading cells undergo profound changes in cell shape and volume as they navigate extracellular spaces along blood vessels and white matter tracts. Volume changes are aided by the concerted release of osmotically active ions, most notably K(+) and Cl(-). Their efflux through ion channels along with obligated water causes rapid cell shrinkage. Suitable ionic gradients must be established and maintained through the activity of ion transport systems. Here, we show that the Sodium-Potassium-Chloride Cotransporter Isoform-1 (NKCC1) provides the major pathway for Cl(-) accumulation in glioma cells. NKCC1 localizes to the leading edge of invading processes, ...

Proteinase-activated receptors-1 and 2 induce electrogenic Cl- secretion in the mouse cecum by distinct mechanisms

AJP: Gastrointestinal and Liver Physiology — Tue, 15 Jun 2010 23:12:18 +0100

In conclusion, PAR1 and PAR2 both induced Cl– secretion in the mouse cecum. This secretion mediated by PAR1 probably occurred by activation of the receptor on the submucosal secretomotor neurons, resulting mainly in the release of tachykinins and activation of the neurokinin-1 receptor, and partly in the release of ACh and activation of the muscarinic and nicotinic receptors. On the other hand, PAR2-mediated Cl– secretion probably occurred by activating the receptor on the epithelial cells. A variety of proteases would induce fluid secretion mediated by PAR1 and PAR2 in the cecum and thereby support bacterial fermentation and participate in mucosal inflammation. (Source: AJP: Gastrointestinal and Liver Physiology)

MedWorm Sponsor Message: Find the best January Sales in the UK.

Deficiency of electroneutral K+-Cl- cotransporter 3 causes a disruption in impulse propagation along peripheral nerves

Glia — Sun, 13 Jun 2010 23:00:00 +0100

In this study, the microscopic examination of KCC isoforms expressed in peripheral nerves showed high expression of KCC2-4 in nodal segments of the axons and in the perinucleus and microvilli of Schwann cells. The KCC inhibitor [[(dihydroindenyl)oxy]alkanoic acid] but not the Na+-K+-2Cl--cotransport inhibitor (bumetanide) dose-dependently suppressed the amplitude and area of compound muscle action potential, indicating the involvement of KCC activity in peripheral nerve conduction. Furthermore, the amplitude and area under the curve were smaller, and the nerve conduction velocity was slower in nerves from KCC3-/- mice than in nerves from wild-type mice, while the expression pattern of KCC2 and KCC4 was similar in KCC3 kockout and wild-type strains. KCC3-/- mice also manifested a prominent ...

Mucus secretion from individual submucosal glands of the ferret trachea

AJP: Lung Cellular and Molecular Physiology — Fri, 11 Jun 2010 20:04:58 +0100

Mucus secretion from individual tracheal glands in adult ferrets was studied with time-lapse optical imaging of mucus droplets under an oil layer. Density of functional glands (determined by responses to 1 µM carbachol) was 1.5 ± 0.3 per mm2 (n = 6). Secretion rates (in pl·min–1·gland–1) were as follows: 4.1 ± 0.7 basal (unstimulated; n = 27, 669 glands), 338 ± 70 to 10 µM forskolin (n = 8, 90 glands), 234 ± 13 to 1 µM VIP (n = 6, 57 glands), 183 ± 92 to 10 µM isoproterenol (n = 3, 33 glands), 978 ± 145 to 1 µM carbachol (n = 11, 131 glands), and 1,348 ± 325 to 10 µM phenylephrine (n = 7, 74 glands). The potency (EC50, in µM) and efficacy (Vmax, in pl·min–1&midd...

Molecular determinants of hyperosmotically activated NKCC1-mediated K+/K+ exchange.

The Journal of Physiology — Sun, 06 Jun 2010 23:00:00 +0100

Authors: Gagnon K, Delpire E Na-K-2Cl cotransport mediates the movement of two Cl(-) ions for one Na(+) and one K(+) ion. Under isosmotic conditions or SPAK/WNK4 activation, the NKCC1-mediated Cl(-) uptake in Xenopus laevis oocytes, as measured using (36)Cl, is twice the value of K(+) uptake, as determined using (86)Rb. Under hyperosmotic conditions, there is a significant activation of the bumetanide-sensitive K(+) uptake with only a minimal increase in bumetanide-sensitive Cl(-) uptake. This suggests that when stimulated by hypertonicity, the cotransporter mediates K(+)/K(+) and Cl(-)/Cl(-) exchange. Although significant stimulation of K(+)/K(+) exchange was observed with NKCC1, a significantly smaller hyperosmotic stimulatory effect was observed with NKCC2. In order to identify the ...

Stimulation of regulatory volume increase (RVI) in avian articular chondrocytes by gadolinium chloride.

Biochemistry and Cell Biology — Mon, 31 May 2010 23:00:00 +0100

Authors: Ong SB, Shah D, Qusous A, Jarvis SM, Kerrigan MJ Chondrocytes, the resident cell-type of articular cartilage, are responsible for the regulation of the extracellular matrix (ECM) in response to their physico-chemical environment. Due to the nature of cartilage loading, chondrocytes are exposed to constant changes in extracellular osmolality with a gradual increase throughout the day. As an increase in osmolality attenuates matrix synthesis, we have studied cell volume regulation (regulatory volume increase (RVI)) after hypertonic challenge and the regulation of RVI by the actin cytoskeleton. Using freshly isolated avian articular chondrocytes, changes in actin organisation were studied by confocal laser scanning microscopy following a 43% increase in extracellular osmolality. ...

Mutation of the Na+-K+-2Cl- cotransporter NKCC2 in mice is associated with severe polyuria and a urea-selective concentrating defect without hyperreninemia

AJP: Renal Physiology — Thu, 20 May 2010 21:18:12 +0100

In conclusion, this novel viable mouse line with a missense Slc12a1 mutation exhibits most of the features of type I Bartter syndrome and may represent a new model for the study of this human disease. (Source: AJP: Renal Physiology)

MedWorm Sponsor Message: Please support the Doctors In Chains campaign for the medics tortured and sentenced for up to 15 years in Bahrain. #FreeDoctors

Na+–K+–2Cl− Cotransport Inhibitor Attenuates Cerebral Edema Following Experimental Stroke via the Perivascular Pool of Aquaporin-4

Neurocritical Care — Tue, 11 May 2010 08:27:15 +0100

Conclusions These data suggest that bumetanide exerts its neuroprotective and anti-edema effects partly via blockade of the perivascular pool of AQP4 and may have therapeutic potential for ischemic stroke in the clinical setting. Content Type Journal ArticleCategory Translational ResearchDOI 10.1007/s12028-010-9376-8Authors Elton R. Migliati, Oregon Health & Science University Department of Neurology Portland OR USAMahmood Amiry-Moghaddam, University of Oslo Center for Molecular Biology and Neuroscience and Department of Anatomy, Institute of Basic Medical Sciences 0317 Oslo NorwayStanley C. Froehner, University of Washington Department of Physiology and Biophysics Seattle WA 98195 USAMarvin E. Adams, University of Washington Department of Physiology and Biophysics S...

Stimulation of human and mouse erythrocyte Na+-K+-2Cl- co-transport by osmotic shrinkage does not involve AMP-activated protein kinase, but is associated with STE20/SPS1-related proline/alanine-rich kinase activation.

The Journal of Physiology — Mon, 03 May 2010 23:00:00 +0100

This study was undertaken to investigate whether the mechanism of increased Na+-K+-2Cl- (NKCC1) co-transporter activation by osmotic shrinkage involved the AMP-activated protein kinase (AMPK). AMPK was found to phosphorylate a recombinant GST-dogfish (1-260) NKCC1 fragment at Ser38 and Ser214, corresponding to Ser77 and Ser242 in human NKCC1, respectively. Incubation of human erythrocytes with 20 muM A-769662 AMPK activator increased Ser242 NKCC1 phosphorylation but did not stimulate 86Rb+ uptake. Under hypertonic conditions in human red blood cells (RBCs) incubated with 0.3 M sucrose, NKCC1 activity increased as measured by bumetanide-sensitive 86Rb+ uptake and AMPK was activated. However, there was no effect of AMPKalpha1 deletion in mouse RBCs on the increased rate of 86Rb+ uptake induc...

Mucus secretion from individual submucosal glands of the ferret trachea.

Am J Physiol Lung Ce... — Thu, 29 Apr 2010 23:00:00 +0100

Authors: Cho HJ, Joo NS, Wine JJ Mucus secretion from individual tracheal glands in adult ferrets was studied with time-lapse optical imaging of mucus droplets under an oil layer. Density of functional glands (determined by responses to 1 muM carbachol) was 1.5 +/- 0.3 per mm(2) (n=6). Secretion rates (in picoliters/min/gland) were as follows: basal (unstimulated): 4.1 +/- 0.7 (n=27, 669 glands); 10 muM forskolin: 338 +/- 70 (n=8, 90 glands); 1 muM VIP: 234 +/- 13 (n=6, 57 glands); 10 muM isoproterenol: 183 +/- 92 (n=3, 33 glands); 1 muM carbachol: 978 +/- 145 (n=11, 131 glands); 10 muM phenylephrine: 1348 +/- 325 (n=7, 74 glands). The potency (EC(50)) and efficacy (V(max)) in picoliters/min/gland) of four agonists was: Forskolin: EC(50) 7.6 muM, V(max) 338 +/- 16; VIP: EC50 1.0 muM, V...

Proteinase-activated receptors-1 and -2 induce electrogenic Cl- secretion in the mouse cecum by distinct mechanisms.

Am J Physiol Gastroi... — Wed, 21 Apr 2010 23:00:00 +0100

In conclusion, PAR(1) and PAR(2) both induced Cl(-) secretion in the mouse cecum. The secretion mediated by PAR(1) probably occurred by activation of the receptor on the submucosal secretomotor neurons, resulting mainly in the release of tachykinins and activation of the neurokinin-1 receptor, and partly in the release of Ach and activation of the muscarinic and nicotinic receptors. On the other hand, PAR(2)-mediated Cl(-) secretion probably occurred by activating the receptor on the epithelial cells. PMID: 20413722 [PubMed - as supplied by publisher] (Source: Am J Physiol Gastroi...)

Basolateral Cl- uptake mechanisms in Xenopus laevis lung epithelium.

Tue, 20 Apr 2010 23:00:00 +0100

This study focuses on basolateral Cl(-) uptake mechanisms in native lungs of Xenopus laevis and the involvement of the Na(+)/K(+)/2Cl(-) cotransporter (NKCC) and HCO(3)(-)/Cl(-) anion exchanger (AE) in particular. Western blot analysis and immunofluorescence staining revealed the expression of the NKCC protein in the Xenopus lung. Ussing chamber experiments demonstrated that the NKCC inhibitors (bumetanide, furosemide) were ineffective at blocking the cotransporter under basal conditions, as well as under pharmacologically stimulated Cl(-) secreting conditions (forskolin and chlorzoxazone application). However, functional evidence for the NKCC was detected by generating a transepithelial Cl(-) gradient. Further we were interested in the involvement of the HCO(3)(-)/Cl(-) anion exchanger to...

MedWorm Sponsor Message: Find the best January Sales in the UK.

Modulation of NaCl absorption by [HCO3-] in the marine teleost intestine is mediated by soluble adenylyl cyclase.

Tue, 20 Apr 2010 23:00:00 +0100

Authors: Tresguerres M, Levin LR, Buck J, Grosell M Intestinal HCO(3)(-) secretion and NaCl absorption are essential for counteracting dehydration in marine teleost fish. We investigated how these two processes are coordinated in toadfish. HCO(3)(-) stimulated a luminal positive short-circuit current (Isc) in intestine mounted in Ussing chamber bathed with the same saline solution on the external and internal sides of the tissue. The Isc increased proportionally to the [HCO(3)(-)] in the bath up to 80 mM NaHCO(3), and it did not occur when NaHCO(3) was replaced with Na(+)-gluconate or with NaHCO(3)(-) in Cl(-)-free saline. 20 mM HCO(3)(-) induced a ~2.5-fold stimulation of Isc, and this [HCO(3)(-)] was used in all subsequent experiments. The HCO(3)(-)-stimulated Isc was prevented or ab...

Heterologous regulation of anion transporters by menthol in human airway epithelial cells.

European Journal of Pharmacology — Tue, 30 Mar 2010 23:00:00 +0100

Authors: Morise M, Ito Y, Matsuno T, Hibino Y, Mizutani T, Ito S, Hashimoto N, Kondo M, Imaizumi K, Hasegawa Y The present study concerns previously unreported effects of menthol, a cyclic terpene alcohol produced by the peppermint herb, on anion transporters in polarized human airway Calu-3 epithelia. Application of menthol (0.01 - 1mM) attenuated transepithelial anion transport, estimated as short-circuit currents (I(SC)), after stimulation by forskolin (10microM) but not before. In contrast, menthol potentiated forskolin-stimulated and -unstimulated apical Cl(-) conductance, which reflected the cystic fibrosis transmembrane conductance regulator (CFTR: the cAMP-regulated Cl(-) channel)-mediated conductance, without correlation to changes in cytosolic cAMP levels. These results indic...

Role of membrane sialic acid and glycophorin protein in thorium induced aggregation and hemolysis of human erythrocytes.

Biochimie — Tue, 30 Mar 2010 23:00:00 +0100

Authors: Kumar A, Ali M, Pandey BN, Hassan PA, Mishra KP Thorium-232 ((232)Th), a natural radionuclide from the actinide family, is abundantly present in monazite and other ores. It is used as one of the prime fuel materials in nuclear industry and may pose an exposure risk to nuclear workers and members of the public. Human erythrocytes, as a classical cellular membrane model, were coincubated with (232)Th in order to elucidate whether this naturally occurring important radionuclide produced perturbations to cell membrane. Present study revealed that erythrocytes underwent aggregation or lysis depending on the ratio of (232)Th to cell. Scanning electron micrographs showed that erythrocytes transformed into equinocytes and/or spherocytes after (232)Th treatment. Further examination of ...

Nitric oxide produced by endothelial nitric oxide synthase promotes diuresis

AJP: Regulatory, Integrative and Comparative Physiology — Mon, 22 Mar 2010 20:44:05 +0100

Extracellular fluid volume is highly regulated, at least in part, by peripheral resistance and renal function. Nitric oxide (NO) produced by NO synthase type 3 (NOS 3) in the nonrenal vasculature may promote fluid retention by reducing systemic vascular resistance and arterial pressure. In contrast, NO produced by renal NOS 3 promotes water excretion by reducing renal vascular resistance, increasing glomerular filtration, and inhibiting reabsorption along the nephron. Thus, the net effect of NO from NOS 3 on urinary volume (UV) is unclear. We hypothesized that NO produced by NOS 3 promotes water excretion primarily due to renal tubular effects. We gave conscious wild-type and NOS 3 –/– mice an acute volume load and measured UV, blood pressure, plasma renin concentration (PRC), ...

AE2 Cl-/HCOFormula exchanger is required for normal cAMP-stimulated anion secretion in murine proximal colon

AJP: Gastrointestinal and Liver Physiology — Fri, 19 Mar 2010 16:55:08 +0100

Anion secretion by colonic epithelium is dependent on apical CFTR-mediated anion conductance and basolateral ion transport. In many tissues, the NKCC1 Na+-K+-2Cl– cotransporter mediates basolateral Cl– uptake. However, additional evidence suggests that the AE2 Cl–/HCO3– exchanger, when coupled with the NHE1 Na+/H+ exchanger or a Na+-HCO3– cotransporter (NBC), contributes to HCO3– and/or Cl– uptake. To analyze the secretory functions of AE2 in proximal colon, short-circuit current (Isc) responses to cAMP and inhibitors of basolateral anion transporters were measured in muscle-stripped wild-type (WT) and AE2-null (AE2–/–) proximal colon. In physiological Ringer, the magnitude of cAMP-stimulated Isc was the same in WT and AE2–/&ndash...

MedWorm Sponsor Message: Please support the Doctors In Chains campaign for the medics tortured and sentenced for up to 15 years in Bahrain. #FreeDoctors

Excitatory Action of GABA in the Terminal Nerve Gonadotropin-Releasing Hormone Neurons

Journal of Neurophysiology — Tue, 16 Mar 2010 15:19:49 +0100

The terminal nerve (TN)-gonadotropin-releasing hormone (GnRH) neurons have been suggested to function as a neuromodulatory system that regulates the motivational and arousal state of the animal and have served as a model system for the study of GnRH neuron physiology. To investigate the synaptic control of the TN-GnRH neurons, we analyzed electrophysiologically the effect of GABA on the TN-GnRH neurons. GABA generally hyperpolarizes most of the neurons in the adult brain by activating GABAA receptors while the activation of GABAA receptors depolarizes some specific neurons in the mature brain. Here we examined the GABAA receptor-mediated responses in the TN-GnRH neurons of adult teleost fish, the dwarf gourami, by means of gramicidin-perforated patch-clamp and cell-attached patch-clamp rec...

Mutation of the Na+-K+-2Cl- Cotransporter NKCC2 in Mice Is Associated with Severe Polyuria and a Urea-selective Concentrating Defect without Hyperreninemia.

American Journal of Physiology. Renal Physiology — Wed, 10 Mar 2010 00:00:00 +0100

In this study, we describe a novel chemically-induced, recessive mutant mouse line termed Slc12a1(I299F) exhibiting late-onset manifestation of Type I Bartter Syndrome. Homozygous mutant mice are viable and exhibit severe polyuria, metabolic alkalosis, marked increase in plasma urea but close to normal creatininemia, hypermagnesemia, hyperprostaglandinuria, hypotension, and osteopenia. Fractional excretion of urea is markedly decreased. In addition, calcium and magnesium excretions are more than doubled compared to wild-type mice, while uric acid excretion is two-fold lower. In contrast to hyperreninemia present in the human disease, plasma renin concentration in homozygotes is not increased. The polyuria observed in homozygotes may be due to the combination of two additive factors, a decr...

Bumetanide Alleviates Epileptogenic and Neurotoxic Effects of Sevoflurane in Neonatal Rat Brain

Anesthesiology — Wed, 24 Feb 2010 13:41:09 +0100

Conclusion: These results support the possibility that excitatory output of sevoflurane-potentiated [gamma]-aminobutyric acid type A/glycine systems may contribute to epileptogenic and neurotoxic effects in early postnatal rats. (C) 2010 American Society of Anesthesiologists, Inc. (Source: Anesthesiology)

Bumetanide-Induced Enlargement of the Rat Intrastrial Space and Effects of a Vasopressin Type 2 Antagonist

Karger Publishers — Tue, 23 Feb 2010 23:00:00 +0100

ORL 2009;71(suppl 1):1015 (DOI:10.1159/000265114) (Source: Karger Publishers)

Bumex (Bumetanide) - updated on RxList

RxList - New and Updated Drug Monographs — Tue, 16 Feb 2010 07:00:00 +0100

Bumex (Bumetanide) drug description - FDA approved labeling for prescription drugs and medications at RxList (Source: RxList - New and Updated Drug Monographs)

MedWorm Sponsor Message: Find the best January Sales in the UK.

Localization and functional characterization of the human NKCC2 isoforms

Acta Physiologica — Mon, 08 Feb 2010 00:00:00 +0100

Conclusion: The human NKCC2 is an example of how differential splicing forms the basis for a diversification of transporter protein function. (Source: Acta Physiologica)

AE2 Cl-/HCO3- Exchanger is Required for Normal cAMP-stimulated Anion Secretion in Murine Proximal Colon.

Am J Physiol Gastroi... — Thu, 28 Jan 2010 00:00:00 +0100

Authors: Gawenis LR, Bradford EM, Alper SL, Prasad V, Shull GE Anion secretion by colonic epithelium is dependent on apical CFTR-mediated anion conductance and basolateral ion transport. In many tissues, the NKCC1 Na(+)-K(+)-2Cl(-) cotransporter mediates basolateral Cl(-) uptake. However, additional evidence suggests that the AE2 Cl(-)/HCO(3)(-) exchanger, when coupled with the NHE1 Na(+)/H(+) exchanger or a Na(+)-HCO(3)(-) cotransporter (NBC), contributes to HCO(3)(-) and/or Cl(-) uptake. To analyze the secretory functions of AE2 in proximal colon, short-circuit current (I(sc)) responses to cAMP and inhibitors of basolateral anion transporters were measured in muscle-stripped wild-type (WT) and AE2-null (AE2(-/-)) proximal colon. In physiologic Ringers, the magnitude of cAMP-stimulate...

Prostaglandin E2-induced colonic secretion in patients with and without colorectal neoplasia

BMC Gastroenterology — Tue, 26 Jan 2010 00:00:00 +0100

Conclusions: Epithelial electrogenic transport is more sensitive to indomethacin in normal colonic mucosa from patients with previous or present colorectal neoplasia compared to colonic mucosa from control patients. Stimulated epithelial electrogenic transport through individual prostanoid subtype receptors EP1, EP2, EP3, and EP4 is not significantly different between neoplasia diseased patients and controls. This indicates that increased indomethacin-sensitive mechanisms in colonic mucosa from neoplasia diseased patients are not related to differences in functional expression of EP receptor subtypes. (Source: BMC Gastroenterology)

The GPA-dependent, spherostomatocytosis mutant AE1 E758K induces GPA-independent, endogenous cation transport in amphibian oocytes

AJP: Cell Physiology — Sat, 23 Jan 2010 00:04:02 +0100

The previously undescribed heterozygous missense mutation E758K was discovered in the human AE1/SLC4A1/band 3 gene in two unrelated patients with well-compensated hereditary spherostomatocytic anemia (HSt). Oocyte surface expression of AE1 E758K, in contrast to that of wild-type AE1, required coexpressed glycophorin A (GPA). The mutant polypeptide exhibited, in parallel, strong GPA dependence of DIDS-sensitive 36Cl– influx, trans-anion-dependent 36Cl– efflux, and Cl–/HCO3– exchange activities at near wild-type levels. AE1 E758K expression was also associated with GPA-dependent increases of DIDS-sensitive pH-independent SO42– uptake and oxalate uptake with altered pH dependence. In marked contrast, the bumetanide- and ouabain-insensitive 86Rb+ influx associated...

Intracellular Na+ and Ca2+ modulation increases the tensile properties of developing engineered articular cartilage

Arthritis and Rheumatism — Wed, 13 Jan 2010 00:00:00 +0100

Significant collagen content and tensile properties are difficult to achieve in tissue-engineered articular cartilage. The aim of this study was to investigate whether treating developing tissue-engineered cartilage constructs with modulators of intracellular Na+ or Ca2+ could increase collagen concentration and construct tensile properties.Inhibitors of Na+ ion transporters and stimulators of intracellular Ca2+ were investigated for their ability to affect articular cartilage development in a scaffoldless, 3-dimensional chondrocyte culture. Using a systematic approach, we applied ouabain (Na+/K+-ATPase inhibitor), bumetanide (Na+/K+/2Cl- tritransporter inhibitor), histamine (cAMP activator), and ionomycin (a Ca2+ ionophore) to tissue-engineered constructs for 1 hour daily on days 10-14 of...

MedWorm Sponsor Message: Please support the Doctors In Chains campaign for the medics tortured and sentenced for up to 15 years in Bahrain. #FreeDoctors

Decreased NKCC1 Activity in Erythrocytes From African Americans With Hypertension and Dyslipidemia.

American Journal of Hypertension — Thu, 31 Dec 2009 00:00:00 +0100

ConclusionsNKCC1 activity is lower in erythrocytes of African Americans with essential hypertension and dyslipidemia than in Caucasian counterparts. We suggest that decreased NKCC1 may contribute to the feature of the pathogenesis of salt-sensitive hypertension seen in African Americans.American Journal of Hypertension 2009; doi:10.1038/ajh.2009.249. PMID: 20044742 [PubMed - as supplied by publisher] (Source: American Journal of Hypertension)

Molecular mechanisms of microvascular failure in central nervous system injury-synergistic roles of NKCC1 and SUR1/TRPM4.

Journal of Neurosurgery — Fri, 25 Dec 2009 00:00:00 +0100

Authors: Simard JM, Kahle KT, Gerzanich V Microvascular failure largely underlies the damaging secondary events that accompany traumatic brain injury (TBI). Changes in capillary permeability result in the extravasation of extracellular fluid, inflammatory cells, and blood, thereby producing cerebral edema, inflammation, and progressive secondary hemorrhage (PSH). Recent work in rat models of TBI and stroke have implicated 2 ion transport proteins expressed in brain endothelial cells as critical mediators of edema formation: the constitutively expressed Na(+)-K(+)-2Cl(-) cotransporter, NKCC1, and the trauma/ischemia-induced SUR1-regulated NC(Ca-ATP) (SUR1/TRPM4) channel. Whereas NKCC1 function requires adenosine 5'-triphosphate (ATP), activation of SUR1/TRPM4 occurs only after ATP deple...

Cerebral Metabolic Alterations in Rats with Diabetic Ketoacidosis: Effects of Treatment with Insulin and Intravenous Fluids and Effects of Bumetanide.

Diabetes — Tue, 22 Dec 2009 00:00:00 +0100

Conclusions: These data demonstrate that cerebral metabolism is significantly compromised during DKA, and further deterioration occurs during early DKA treatment, consistent with possible effects of cerebral hypoperfusion and "reperfusion injury". Treatment with bumetanide may help to diminish the adverse effects of initial treatment with insulin/saline. PMID: 20028943 [PubMed - as supplied by publisher] (Source: Diabetes)

Sex differences in adaptive downregulation of pre-macula densa sodium transporters with ANG II infusion in mice

AJP: Renal Physiology — Sat, 19 Dec 2009 00:09:53 +0100

An increase in blood pressure (BP) due to angiotensin II (ANG II) infusion or other means is associated with adaptive pressure natriuresis due to reduced sodium reabsorption primarily in proximal tubule (PT) and thick ascending limb (TAL). We tested the hypothesis that male and female mice would show differential response to ANG II infusion with regard to the regulation of the protein abundance of sodium transporters in the PT and TAL and that these responses would be modulated by aging. Young (~3 mo) and old (~21 mo) male and female mice were infused with ANG II at 800 ng·kg body wt–1·min–1 by osmotic minipump for 7 days or received a sham operation. ANG II increased mean arterial pressure (MAP), measured by radiotelemetry, significantly more in male mice of both...

Developmental and functional studies of the SLC12 gene family members from Drosophila melanogaster

AJP: Cell Physiology — Thu, 17 Dec 2009 01:40:40 +0100

The electroneutral cation-chloride cotransporter gene family, SLC12, contains nine members in vertebrates. These include seven sodium and/or potassium-coupled chloride transporters and two membrane proteins of unknown function. Although SLC12 family members have been identified in a number of lower species, the functional properties of these proteins are unknown. There are five SLC12 homologues in Drosophila melanogaster, including at least one member on each of the four main branches of the vertebrate phylogenetic tree. We have employed in situ hybridization to study the expression patterns of the Drosophila SLC12 proteins during embryonic development. Our studies indicate that all five members of this family are expressed during early embryogenesis (stages 1–6), but that spatial an...

MedWorm Sponsor Message: Find the best January Sales in the UK.

Functional Expression of the Na-K-2Cl Cotransporter NKCC2 in Mammalian Cells Fails to Confirm the Dominant-negative Effect of the AF Splice Variant [Membrane Transport, Structure, Function, and Biogenesis]

Journal of Biological Chemistry — Fri, 11 Dec 2009 14:37:31 +0100

The renal bumetanide-sensitive Na-K-2Cl cotransporter (NKCC2) is the major salt transport pathway in the apical membrane of the mammalian thick ascending limb. It is differentially spliced and the three major variants (A, B, and F) differ in their localization and transport characteristics. Most knowledge about its regulation comes from experiments in Xenopus oocytes as NKCC2 proved difficult to functionally express in a mammalian system. Here we report the cloning and functional expression of untagged and unmodified versions of the major splice variants from ferret kidney (fNKCC2A, -B, and -F) in human embryonic kidney (HEK) 293 cells. Many NKCC2 antibodies used in this study detected high molecular weight forms of the transfected proteins, probably NKCC2 dimers, but not the monomers. Int...

Secondhand smoke inhibits both Cl- and K+ conductances in normal human bronchial epithelial cells

Respiratory Research — Fri, 27 Nov 2009 00:00:00 +0100

Secondhand smoke (SHS) exposure is an independent risk factor for asthma, rhinosinusitis, and more severe respiratory tract infections in children and adults. Impaired mucociliary clearance with subsequent mucus retention contributes to the pathophysiology of each of these diseases, suggesting that altered epithelial salt and water transport may play an etiological role. To test the hypothesis that SHS would alter epithelial ion transport, we designed a system for in vitro exposure of mature, well-differentiated human bronchial epithelial cells to SHS. We show that SHS exposure inhibits cAMP-stimulated, bumetanide-sensitive anion secretion by 25 to 40% in a time-dependent fashion in these cells. Increasing the amount of carbon monoxide to 100 ppm from 5 ppm did not increase the amount of i...

The glycophorin A (GPA)-dependent, spherostomatocytosis mutant AE1 E758K induces GPA-independent, endogenous cation transport in amphibian oocytes.

American Journal of Physiology. Cell Physiology — Wed, 11 Nov 2009 00:00:00 +0100

Authors: Stewart AK, Vandorpe DH, Heneghan JF, Chebib F, Stolpe K, Akhavein A, Edelman EJ, Maksimova Y, Gallagher PG, Alper SL The previously undescribed, heterozygous missense mutation E758K was discovered in the human AE1/SLC4A1/Band 3 gene in two unrelated patients with well-compensated spherostomatocytic anemia (HSt). AE1 E758K oocyte surface expression, unlike that of wildtype AE1, required coexpressed glycophorin A (GPA). The mutant polypeptide exhibited, in parallel, strong GPA-dependence of DIDS-sensitive (36)Cl(-) influx, trans-anion-dependent (36)Cl(-) efflux, and Cl(-)/HCO(3)(-) exchange activities at near wildtype levels. AE1 E758K expression was also associated with GPA-dependent increases of DIDS-sensitive pH-independent sulfate uptake and oxalate uptake of altered pH-dep...

Sex differences in adaptive down-regulation of pre-macula densa sodium transporters with Ang II infusion in mice.

American Journal of Physiology. Renal Physiology — Wed, 04 Nov 2009 00:00:00 +0100

Authors: Tiwari S, Li L, Riazi S, Halagappa VK, Ecelbarger CM An increase in blood pressure (BP) due to angiotensin II (Ang II) infusion or other means is associated with adaptive pressure natriuresis due to reduced sodium reabsorption primarily in proximal tubule (PT) and thick ascending limb (TAL). We tested the hypothesis that male and female mice would show differential response to Ang II infusion with regard to the regulation of the protein abundance of sodium transporters in the PT and TAL, and whether these responses would be modulated by aging. Young (~3 months) and old (~21 months) male and female mice were infused with Ang II @ 800 ng/kg*bw/min by osmotic minimpump for 7 days or received a sham operation. Ang II increased MAP, measured by radiotelemetry, significantly more in...

Hymenolepis diminuta: Effect of infection on ion transport in colon and blood picture of rats.

Experimental Parasitology — Tue, 03 Nov 2009 00:00:00 +0100

Authors: Kosik-Bogacka DI, Baranowska-Bosiacka I, Salamatin R The aim of this study was to examine the effect of an infection with Hymenolepis diminuta on ion transport in an isolated colon and blood picture of rats. Fifty rats were orally infected with 5 cysticercoids of H. diminuta. The experimental groups of rats were assigned to four groups: group I - 8 days post-infection (dpi), group II - 16 dpi, group III - 40 dpi and group IV- 60 dpi. The control group comprised non-infected rats. The experiments consisted of measuring the transepithelial electrical potential difference (PD) and the transepithelial electrical resistance (R) of the rat colon under controlled conditions as well as during mechanical stimulation (MS) using a modified Ussing chamber. Ion transport was modified using...

MedWorm Sponsor Message: Please support the Doctors In Chains campaign for the medics tortured and sentenced for up to 15 years in Bahrain. #FreeDoctors

Activity-mediated plasticity of GABA equilibrium potential in rat hippocampal CA1 neurons.

Experimental Neurology — Wed, 28 Oct 2009 00:00:00 +0100

Authors: Yang B, Tadavarty R, Xu JY, Sastry BR The equilibrium potential (E(GABA-PSC)) for gamma-aminobutyric acid (GABA) A receptor mediated inhibitory postsynaptic currents (PSCs) in hippocampal CA1 pyramidal neurons shifts when theta-burst stimulation (4 pulses at 100 Hz in each burst in a train consisting of 5 bursts with an inter-burst interval of 200 ms, the train repeated thrice at 30 s intervals) is applied to the input. E(GABA-PSC) is regulated by K(+)/Cl(-)co-transporter (KCC2). GABA(B) receptors are implicated in modulating KCC2 levels. In the current study, the involvement of KCC2 as well as GABA(B) receptors in theta-burst-mediated shifts in E(GABA-PSC,) were examined. Whole-cell patch recordings were made from hippocampal CA1 pyramidal neurons (from 9-12 day old rats), in...

Why funding epilepsy research matters

Thrive, Children's Hospital Boston — Mon, 26 Oct 2009 14:04:29 +0100

Last night, Frances Jensen, MD, senior associate in Neurology, was featured in a piece on 60 Minutes about the prevalence of epilepsy and the importance of funding research into its cure. Watch the piece here, then keep reading below as Jensen describes how epilepsy is often overlooked as a public health problem and how researchers like her are trying to stop it in its tracks. Also watch below as Jensen shows Katie Couric what an epilepsy looks like from a molecular perspective. Watch CBS News Videos Online By Frances Jensen, MD Last night, research by myself and my team was featured on 60 Minutes in a wonderful story about the impact that epilepsy has on the people with it and the challenges of getting the public – including the agencies that fund research – to pay the disease the at...

Frances Jensen on 60 Minutes: Why funding epilepsy research is important

Thrive, Children's Hospital Boston — Mon, 26 Oct 2009 14:04:29 +0100

Unilateral Ureteral Obstruction Alters Expression of Acid-Base Transporters in Rat Kidney

The Journal of Urology — Tue, 20 Oct 2009 00:00:00 +0100

Conclusions: The expression of renal acid-base transporters is markedly decreased in the obstructed kidney, which may be responsible for the contribution of impaired renal H+ excretion and HCO3− reabsorption to the urinary acidification defect in response to unilateral ureteral obstruction. (Source: The Journal of Urology)

A Comprehensive Review of the Loop Diuretics: Should Furosemide Be First Line? (November)(CE).

The Annals of Pharmacotherapy — Mon, 19 Oct 2009 23:00:00 +0100

CONCLUSIONS: Growing evidence demonstrates more favorable pharmacokinetic profiles of torsemide and bumetanide compared with furosemide. Furthermore, torsemide may be more efficacious and safer than furosemide in patients with HF. A trial comparing all 3 drugs would be required to confirm torsemide as the primary loop diuretic in patients with HF, but based upon limited current evidence, we recommend torsemide over furosemide. Currently, little evidence exists to support either torsemide or bumetanide as first-line treatment over furosemide in patients with other edematous disease states. PMID: 19843838 [PubMed - as supplied by publisher] (Source: The Annals of Pharmacotherapy)

MedWorm Sponsor Message: Find the best January Sales in the UK.

Developmental and functional studies of the SLC12 gene family members from Drosophila melanogaster.

American Journal of Physiology. Cell Physiology — Tue, 13 Oct 2009 23:00:00 +0100

Authors: Sun Q, Tian E, Turner RJ, Ten Hagen K The electroneutral cation-chloride cotransporter gene family, SLC12, contains nine members in vertebrates. These include seven sodium and/or potassium-coupled chloride transporters and two membrane proteins of unknown function. Although SLC12 family members have been identified in a number of lower species, the functional properties of these proteins are unknown. There are five SLC12 homologues in Drosophila melanogaster including at least one member on each of the four main branches of the vertebrate phylogenetic tree. We have employed in situ hybridization to study the expression patterns of the Drosophila SLC12 proteins during embryonic development. Our studies indicate that all five members of this family are expressed during early emb...

GABAergic signaling induces divergent neuronal Ca2+ responses in the suprachiasmatic nucleus network

European Journal of Neuroscience — Sun, 11 Oct 2009 23:00:00 +0100

Intercellular communication between [gamma]-aminobutyric acid (GABA)ergic suprachiasmatic nucleus (SCN) neurons facilitates light-induced phase changes and synchronization of individual neural oscillators within the SCN network. We used ratiometric Ca2+ imaging techniques to record changes in the intracellular calcium concentration ([Ca2+]i) to study the role of GABA in interneuronal communication and the response of the SCN neuronal network to optic nerve stimulations that mimic entraining light signals. Stimulation of the retinohypothalamic tract (RHT) evoked divergent Ca2+ responses in neurons that varied regionally within the SCN with a pattern that correlated with those evoked by pharmacological GABA applications. GABAA and GABAB receptor agonists and antagonists were used to evaluate...

Thrombin potentiates d-aspartate efflux from cultured astrocytes under conditions of K+ homeostasis disruption

Journal of Neurochemistry — Sat, 03 Oct 2009 00:00:00 +0100

This study examined the effect of thrombin on glutamate efflux from rat cortical cultured astrocytes using 3H-d-aspartate as radiotracer. The glutamate efflux was initiated by addition of 100 mM K+ plus 1 mM ouabain (K/O) to replicate extracellular and intracellular ionic changes that occur during cerebral ischemia. Upon exposure to K/O, astrocytes swelled slowly and progressively with no evidence of volume regulation. The K/O-induced swelling was inhibited by 65% with bumetanide and 25% with BaCl2, suggesting contribution of Na+/K+/Cl[minus] co-transporter and Kir channels. K/O-elicited 3H-d-aspartate that consisted of two phases. The first transient component of the release corresponded to 13.5% of total 3H-d-aspartate loaded. It was markedly reduced (61%) by the glutamate transporter bl...

Chloride transport in mitochondrion-rich cells of euryhaline tilapia (Oreochromis mossambicus) larvae

AJP: Cell Physiology — Thu, 01 Oct 2009 21:03:08 +0100

This study provides direct and convincing evidence for Cl– transport by MRCs of SW- and FW-acclimated euryhaline tilapia and the involvement of an apical NCC in Cl– uptake of MRCs of FW-acclimated fish. (Source: AJP: Cell Physiology)

Genistein stimulates electrogenic Cl- secretion via phosphodiesterase modulation in the mouse jejunum

AJP: Cell Physiology — Fri, 04 Sep 2009 22:12:33 +0100

Previously, we demonstrated that genistein stimulated Cl– secretion in the mouse jejunum (Baker MJ and Hamilton KL, Am J Physiol Cell Physiol 287: C1636–C1645, 2004); however, the mode of action of genistein still remains unclear. Here, we examined the activation of Cl– secretion by the modulation of phosphodiesterases (PDEs) by genistein (75 µM) in the mouse jejunum with the Ussing short-circuit current (Isc) technique. Drugs tested included theophylline (10 mM), a nonspecific PDE inhibitor; 8-methoxymethyl-3-isobutyl-1-methylxanthine (8-MM-IBMX; 100 µM), erythro-9-(2-hydroxyl-3-nonyl)-adenine (EHNA; 40 µM), milrinone (100 µM), and rolipram (40 and 100 µM), which are specific inhibitors of PDE1–PDE4, respectively. Theophylline stimulat...

MedWorm Sponsor Message: Please support the Doctors In Chains campaign for the medics tortured and sentenced for up to 15 years in Bahrain. #FreeDoctors

Excitatory GABAergic Activation of Cortical Dividing Glial Cells

Cerebral Cortex — Wed, 05 Aug 2009 23:00:00 +0100

Adult neocortex contains dividing satellite glia population even though their characteristics and functions have still remained unknown. Nestin+/NG2+ cells as major fraction of dividing glial cells express bicuculline-sensitive -aminobutyric acid A (GABAA) receptors and receive GABAergic inputs. Due to their high [Cl–]i, GABAergic activation depolarized the cells and then induced Ca2+ influx into them. To assess an effect of this GABAergic excitation, we looked for the expression of neurotrophic factors. Among them, we detected the expression of brain-derived neurotrophic factor (BDNF) on the cells. The level of BDNF expression was elevated after cortical ischemia, and this elevation was blocked by bumetanide, an inhibitor for NKCC1 that blocks the GABAergic depolarization. Furthermo...

Chloride Transport in Mitochondrion-Rich Cells of Euryhaline Tilapia (Oreochromis mossambicus) Larvae.

American Journal of Physiology. Cell Physiology — Tue, 04 Aug 2009 23:00:00 +0100

This study provides direct and convincing evidence for Cl(-) transport by MRCs of SW- and FW-acclimated euryhaline tilapia, and the involvement of an apical NCC in Cl(-) uptake of MRCs of FW-acclimated fish. Key words: Na+-Cl- cotransporter, osmoregulation, gills, ionoregulation. PMID: 19657057 [PubMed - as supplied by publisher] (Source: American Journal of Physiology. Cell Physiology)

Cerebral microvascular endothelial cell Na/H exchange: evidence for the presence of NHE1 and NHE2 isoforms and regulation by arginine vasopressin

AJP: Cell Physiology — Wed, 29 Jul 2009 23:00:00 +0100

Blood-brain barrier (BBB) Na transporters are essential for brain water and electrolyte homeostasis. However, they also contribute to edema formation during the early hours of ischemic stroke by increased transport of Na from blood into brain across an intact BBB. We previously showed that a luminal BBB Na-K-Cl cotransporter is stimulated by hypoxia, aglycemia, and AVP and that inhibition of the cotransporter by intravenous bumetanide significantly reduces edema and infarct in the rat middle cerebral artery occlusion (MCAO) model of stroke. More recently, we found evidence that intravenous cariporide (HOE-642), a highly potent Na/H exchange inhibitor, also reduces brain edema after MCAO. The present study was conducted to investigate which Na/H exchange protein isoforms are present in BBB ...

[Small intestine] Structural and functional changes of the duodenum in human norovirus infection

Gut — Thu, 09 Jul 2009 23:00:00 +0100

Conclusions: Norovirus infection leads to epithelial barrier dysfunction paralleled by a reduction of sealing tight junctional proteins and an increase in epithelial apoptosis, which may partly be mediated by increased cytotoxic intraepithelial lymphocytes. Furthermore, active anion secretion is markedly stimulated. Thus, the diarrhoea in norovirus infection is driven by both a leak flux and a secretory component. (Source: Gut)

Prenatal programming of rat thick ascending limb chloride transport by low-protein diet and dexamethasone

AJP: Regulatory, Integrative and Comparative Physiology — Wed, 01 Jul 2009 23:00:00 +0100

This study demonstrates that insults administered to the fetus can program altered sodium transport. Increased tubular sodium transport is a likely cause for the hypertension by prenatal programming. (Source: AJP: Regulatory, Integrative and Comparative Physiology)

MedWorm Sponsor Message: Find the best January Sales in the UK.

An environmentally friendly reflectometric method for bumetanide determination in pharmaceuticals.

Tue, 30 Jun 2009 23:00:00 +0100

Authors: Pollo F, Sequinel R, Rufino JL, Los Weinert P, Pezza HR, Pezza L This paper describes a green analytical procedure for the determination of bumetanide using diffuse reflectance spectroscopy. The proposed method is based on reflectance measurements of a violet compound produced from a spot test reaction between bumetanide and p-dimethylaminocinnamaldehyde (p-DAC) in an acid medium, using filter paper as a solid support. The best conditions for the reaction have been found by experimental design methodologies. All reflectance measurements were carried out at 525 nm, and the linear range was from 1.37 x 10(-4) to 1.37 x 10(-3) mol L(-1), with a correlation coefficient of 0.998. The detection limit was estimated to be 3.98 x 10(-5) mol L(-1). Five commercial medicines containing b...

Electrogenic Cl− secretion does not occur in the ileum of the Australian common brushtail possum, Trichosurus vulpecula, due to low levels of expression of the NaK2Cl cotransporter, NKCC1

Tue, 30 Jun 2009 15:40:31 +0100

Abstract The colon of the brushtail possum does not have an electrogenic secretory response. Given the functional significance of electrogenic Cl− secretion in the intestine of eutherian mammals, we have investigated the secretory response in the small intestine of this marsupial. In the Ussing chamber cAMP-dependent secretagogues stimulated a sustained increase in ileal short-circuit current (Isc), whereas Ca2+-dependent secretagogues induced a transient increase. Both the responses were inhibited by mucosal addition of the anion channel blocker 5-nitro-2-(3-phenylpropylamino) benzoic acid (100 μmol l−1), consistent with an anion secretory response. However, the responses were not inhibited by serosal bumetanide (10 μmol l−1) and were independent...

The role of chloride transport in the control of the membrane potential in skeletal muscle--theory and experiment.

Biophysical Chemistry — Sun, 28 Jun 2009 03:47:53 +0100

We present a model for the control of the transmembrane potential of mammalian skeletal muscle cell. The model involves active and passive transport of Na(+), K(+), and Cl(-). As we check the model against experimental measurements on murine skeletal muscle cells, we find that the model can account for the observed bistability of the transmembrane potential at low extracellular potassium concentration. The effect of bumetanide, a blocker of the Na,K,2Cl-cotransporter, is measured and modeled. A hyperosmotic medium is known to stimulate the Na,K,2Cl-cotransporter and we also measure and model the effects of such a medium. Increased chloride transport has two effects on the interval along the extracellular potassium concentration axis where the system is bistable: the interval is shifted tow...

Genistein stimulates electrogenic Cl- secretion via phosphodiesterase modulation in the mouse jejunum.

American Journal of Physiology. Cell Physiology — Tue, 16 Jun 2009 23:00:00 +0100

Authors: Chao PC, Hamilton KL Previously, we demonstrated that genistein stimulated Cl(-) secretion in the mouse jejunum (Baker and Hamilton, Am. J. Physiol. Cell Physiol. 287:C1636-C1645, 2004); however, the mode of action of genistein still remains unclear. Here, we examined the activation of Cl(-) secretion by the modulation of phosphodiesterases (PDEs) by genistein (75 microM) in the mouse jejunum with the Ussing short circuit current (Isc) technique. Drugs tested included theophylline (10 mM) a non-specific PDE inhibitor; 8-MM-IBMX (100 microM), EHNA (40 microM), milrinone (100 microM) and rolipram (40 and 100 microM), which are specific inhibitors of PDE1 - PDE4, respectively. Theophylline stimulated a bumetanide sensitive Isc, indicative of Cl(-) secretion, and abolished geniste...

[Membrane Transport, Structure, Function, and Biogenesis] In Situ Measurement of Airway Surface Liquid [K+] Using a Ratioable K+-sensitive Fluorescent Dye

Journal of Biological Chemistry — Fri, 29 May 2009 04:00:00 +0100

The airway surface liquid (ASL) is the thin fluid layer lining airway surface epithelial cells, whose volume and composition are tightly regulated and may be abnormal in cystic fibrosis (CF). We synthesized a two-color fluorescent dextran to measure ASL [K+], TAC-Lime-dextran-TMR, consisting of a green-fluorescing triazacryptand K+ ionophore-Bodipy conjugate, coupled to dextran, together with a red fluorescing tetramethylrhodamine reference chromophore. TAC-Lime-dextran-TMR fluorescence was K+-selective, increasing >4-fold with increasing [K+] from 0 to 40 mm. In well differentiated human airway epithelial cells, ASL [K+] was 20.8 ± 0.3 mm and decreased by inhibition of the Na+/K+ pump (ouabain), ENaC (amiloride), CF transmembrane conductance regulator (CFTRinh-172), or K+ channe...

MedWorm Sponsor Message: Please support the Doctors In Chains campaign for the medics tortured and sentenced for up to 15 years in Bahrain. #FreeDoctors

Bumetanide, an NKCC1 Antagonist, Does Not Prevent Formation of Epileptogenic Focus but Blocks Epileptic Focus Seizures in Immature Rat Hippocampus

Journal of Neurophysiology — Tue, 26 May 2009 04:00:00 +0100

We report that bumetanide, a NKCC1 antagonist, reduces driving force of GABA-mediated currents (DFGABA) in neonatal hippocampal neurons and blocks the giant depolarizing potentials (GDPs), a spontaneous pattern of network activity. In the preparation composed of two intact interconnected hippocampi, bumetanide did not prevent generation of kainate-induced seizures, their propagation to the contralateral hippocampus, and formation of an epileptogenic mirror focus. However, in the isolated mirror focus, bumetanide effectively blocked spontaneous epileptiform activity transforming it to the GDP-like activity pattern. Bumetanide partially reduced DFGABA and therefore the excitatory action of GABA in epileptic neurons. Therefore bumetanide is a potent anticonvulsive agent although it cannot pre...

Cerebral Microvascular Endothelial Cell Na/H Exchange: Evidence for the Presence of NHE1 and NHE2 Isoforms and Regulation by Arginine Vasopressin.

American Journal of Physiology. Cell Physiology — Tue, 19 May 2009 23:00:00 +0100

Authors: Lam TI, Wise PM, O'Donnell ME Blood-brain barrier (BBB) Na transporters are essential for brain water and electrolyte homeostasis. However, they also contribute to edema formation during the early hours of ischemic stroke through increased transport of Na from blood into brain across an intact BBB. We have shown previously that a luminal BBB Na-K-Cl cotransporter is stimulated by hypoxia, aglycemia and arginine vasopressin (AVP), and that inhibition of the cotransporter by intravenous bumetanide significantly reduces edema and infarct in the rat middle cerebral artery occlusion (MCAO) model of stroke. More recently we have found evidence that intravenous cariporide (HOE-642), a highly potent Na/H exchange inhibitor, also reduces brain edema after MCAO. The present study was co...

GABAA Receptors Mediate Excitation in Adult Rat GnRH Neurons.

Biology of Reproduction — Wed, 08 Apr 2009 04:00:00 +0100

In this study, we investigated the GABA-induced changes in [Ca(2+)]i of GnRH neurons from GnRH-EGFP rats both to confirm the depolarizing action of GABA and to further examine the developmental and estrous cycle-dependent modulations of GABA action. GABA increased [Ca(2+)]i in GnRH neurons in all developmental stages of both sexes. GABA also increased [Ca(2+)]i in adult female GnRH neurons prepared in the afternoon at each estrous cycle stage. The percentages of neurons with increased [Ca(2+)]i were 90% in proestrus, 59% in estrus, 84% in diestrus I, and 89% in diestrus II. In GnRH neurons prepared from adult females in the morning, however, the percentage was significantly lower than in those prepared in the afternoon except in estrus. The percentage was also lower in adult males than in ...

The influence of commonly used immunosuppressive drugs on the small bowel functions - a comparative experimental study.

Annals of Transplantation — Wed, 01 Apr 2009 04:00:00 +0100

CONCLUSIONS: In conclusion, the analyzed immunosuppressive drugs had no direct and immediate influence on gastrointestinal function in therapeutic concentrations. However, toxic concentrations of mycophenolate mofetil, enteric coated MPA, and everolimus might be of importance for local effects on small bowel function due to oral application.<br /> <br /> <br /> PMID: 19487793 [PubMed - in process] (Source: Annals of Transplantation)