MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Brain Cell Biology' source. Sat, 10 Oct 2009 19:28:59 +0100 http://www.medworm.com/index.php?rid=2218312&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19238548%26dopt%3DAbstract Authors: Zhou LH, Han S, Xie YY, Wang LL, Yao ZB In the peripheral nervous system (PNS), root avulsion causes motoneuron degeneration, but the majority of motoneurons can survive axotomy. In order to study the mechanism of motoneuron degeneration, we compared the expression patterns of c-jun and neuronal nitric oxide synthase (nNOS), the well-known molecular players in PNS regeneration and degeneration, among adult rats having undergone axotomy (Ax), avulsion (Av), or pre-axotomy plus secondary avulsion (Ax + Av) of the brachial plexus. Our results showed that the highest and longest-lasting c-jun activation occurred in Ax, which was much stronger than those in Av and Ax + Av. The time course and intensity of c-jun expression in Ax + Av were similar to those in Av except on day 1, whil... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=2218312 Tue, 24 Feb 2009 05:00:00 +0100 2218312 http://www.medworm.com/index.php?rid=2192288&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19219551%26dopt%3DAbstract Authors: Kee MZ, Wuskell JP, Loew LM, Augustine GJ, Sekino Y We have assessed the utility of five new long-wavelength fluorescent voltage-sensitive dyes (VSD) for imaging the activity of populations of neurons in mouse brain slices. Although all the five were capable of detecting activity resulting from activation of the Schaffer collateral-CA1 pyramidal cell synapse, they differed significantly in their properties, most notably in the signal-to-noise ratio of the changes in dye fluorescence associated with neuronal activity. Two of these dyes, Di-2-ANBDQPQ and Di-1-APEFEQPQ, should prove particularly useful for imaging activity in brain tissue and for combining VSD imaging with the control of neuronal activity via light-activated proteins such as channelrhodopsin-2 and halorhodopsin. ... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=2192288 Sat, 14 Feb 2009 05:00:00 +0100 2192288 http://www.medworm.com/index.php?rid=2153557&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19184439%26dopt%3DAbstract Authors: Augustine GJ PMID: 19184439 [PubMed - as supplied by publisher] (Source: Brain Cell Biology) Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=2153557 Wed, 28 Jan 2009 05:00:00 +0100 2153557 http://www.medworm.com/index.php?rid=2093590&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19132532%26dopt%3DAbstract We examined the distribution of beta-catenin and endogenous blood serum albumin at the ultrastructural level in blood microvessels (capillaries) from brains of control and trisomic Ts65Dn mice. Morphological examination revealed an increased immunolabeling for beta-catenin in endothelial substructures of the capillary network, such as intercellular junctions, cytoplasm, and nuclei. These immunosignals were significantly increased in all endothelial substructures from trisomic mice. These changes, however, did not affect the blood-brain barrier function of the entire microvascular network, because the increased uptake of albumin by endothelial cells and the eventual escape of this protein (microleakage) into the perivascular neuropil were noted only in a few capillary profiles. Nevertheless... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=2093590 Fri, 09 Jan 2009 05:00:00 +0100 2093590 http://www.medworm.com/index.php?rid=2093589&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19132533%26dopt%3DAbstract We examined the post-translational modification of intracellular proteins by beta-O-linked N-acetylglucosamine (O-GlcNAc) with regard to neurofilament phosphorylation in the developing chick optic tectum. A regulated developmental pattern of O-GlcNAcylation was discovered in the developing brain. Most notably, discernible staining occurs along radial glial filaments but not along neuronal filaments in vivo. Immunohistochemical analyses in sections of progressive stages of development suggest upregulation of O-GlcNAc in the ependyma, tectofugal neuron bodies, and radial glial processes, but not in axons. In contrast, double-label immunostaining of monolayer cultures made from dissociated embryonic day (E) 7 optic tecta revealed O-GlcNAcylation of most axons. Labeling of brain sections toget... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=2093589 Fri, 09 Jan 2009 05:00:00 +0100 2093589 http://www.medworm.com/index.php?rid=2093588&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19132534%26dopt%3DAbstract Authors: Tokumaru H, Shimizu-Okabe C, Abe T Although the binding of synaphin (also called complexin) to the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex is critical for synaptic vesicle exocytosis, the exact role of synaphin remains unclear. Here, we show that synaphin directly binds to synaptotagmin 1, a major Ca(2+) sensor for fast neurotransmitter release, in a 1:1 stoichiometry. Mapping of the synaphin site involved in synaptotagmin 1 binding revealed that the C-terminal region is essential for the interaction between these two proteins. Binding was sensitive to ionic strength, suggesting the involvement of charged residues in the C-terminus region. Mutation of the seven consecutive glutamic acid residues (residues 108-114) at the C-terminal... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=2093588 Fri, 09 Jan 2009 05:00:00 +0100 2093588 http://www.medworm.com/index.php?rid=1903229&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18941897%26dopt%3DAbstract Authors: Yasuda R, Augustine GJ PMID: 18941897 [PubMed - as supplied by publisher] (Source: Brain Cell Biology) Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1903229 Wed, 22 Oct 2008 04:00:00 +0100 1903229 http://www.medworm.com/index.php?rid=1903228&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18941898%26dopt%3DAbstract Authors: Vincent P, Gervasi N, Zhang J Signaling cascades involving cyclic nucleotides play key roles in signal transduction in virtually all cell types. Elucidation of the spatiotemporal regulation of cyclic nucleotide signaling requires methods for tracking the dynamics of cyclic nucleotides and the activities of their regulators and effectors in the native biological context. Here we review a series of genetically encoded FRET-based probes for real-time monitoring of cyclic nucleotide signaling with a particular focus on their implementation in neurons. Current data indicate that neurons have a very active metabolism in cyclic nucleotide signaling, which is tightly regulated through a variety of homeostatic regulations. PMID: 18941898 [PubMed - as supplied by publisher] (Source:... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1903228 Wed, 22 Oct 2008 04:00:00 +0100 1903228 http://www.medworm.com/index.php?rid=1903227&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18941899%26dopt%3DAbstract Authors: Fukano T, Shimozono S, Miyawaki A For quantitative measurements of Ca(2+) concentration ([Ca(2+)]), ratiometric dyes are preferable, because the use of such dyes allows for correction of uneven loading or partitioning of dye within the cell as well as variations in cell thickness. Although dual-excitation ratiometric dyes for measuring [Ca(2+)], such as Fura-2, Fura-Red, and ratiometric-pericam, are widely used for a variety of applications, it has been difficult to use them for monitoring very fast Ca(2+) dynamics or Ca(2+) changes in highly motile cells. To overcome this problem, we have developed three new dual-excitation ratiometry systems. (1) A system in which two laser beams are alternated on every scanning line, allowing us to obtain confocal images using dual-excitati... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1903227 Wed, 22 Oct 2008 04:00:00 +0100 1903227 http://www.medworm.com/index.php?rid=1903226&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18941900%26dopt%3DAbstract Authors: Fernandez-Alfonso T, Ryan TA Using pHluorin-tagged synaptic vesicle proteins we have examined the partitioning of these probes into recycling and nonrecycling pools at hippocampal nerve terminals in cell culture. Our studies show that for three of the major synaptic vesicle components, vGlut-1, VAMP-2, and Synaptotagmin I, ~50-60% of the tagged protein appears in a recycling pool that responds readily to sustained action potential stimulation by mobilizing and fusing with the plasma membrane, while the remainder is targeted to a nonrecycling, acidic compartment. The fraction of recycling and nonrecycling (or resting) pools varied significantly across boutons within an individual axon, from 100% resting (silent) to 100% recycling. Single-bouton bleaching studies show that recyc... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1903226 Wed, 22 Oct 2008 04:00:00 +0100 1903226 http://www.medworm.com/index.php?rid=1903225&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18941901%26dopt%3DAbstract Authors: Hires SA, Tian L, Looger LL Genetically encoded calcium indicators (GECIs), based on recombinant fluorescent proteins, have been engineered to observe calcium transients in living cells and organisms. Through observation of calcium, these indicators also report neural activity. We review progress in GECI construction and application, particularly toward in vivo monitoring of sparse action potentials (APs). We summarize the extrinsic and intrinsic factors that influence GECI performance. A simple model of GECI response to AP firing demonstrates the relative significance of these factors. We recommend a standardized protocol for evaluating GECIs in a physiologically relevant context. A potential method of simultaneous optical control and recording of neuronal circuits is present... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1903225 Wed, 22 Oct 2008 04:00:00 +0100 1903225 http://www.medworm.com/index.php?rid=1896767&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18931914%26dopt%3DAbstract Authors: Zhao S, Cunha C, Zhang F, Liu Q, Gloss B, Deisseroth K, Augustine GJ, Feng G The ability to control and manipulate neuronal activity within an intact mammalian brain is of key importance for mapping functional connectivity and for dissecting the neural circuitry underlying behaviors. We have previously generated transgenic mice that express channelrhodopsin-2 for light-induced activation of neurons and mapping of neural circuits. Here we describe transgenic mice that express halorhodopsin (NpHR), a light-driven chloride pump that can be used to silence neuronal activity via light. Using the Thy-1 promoter to target NpHR expression to neurons, we found that neurons in these mice expressed high levels of NpHR-YFP and that illumination of cortical pyramidal neurons expressing NpH... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1896767 Fri, 17 Oct 2008 04:00:00 +0100 1896767 http://www.medworm.com/index.php?rid=1873756&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18850274%26dopt%3DAbstract Authors: Berglund K, Schleich W, Wang H, Feng G, Hall WC, Kuner T, Augustine GJ Here we survey a molecular genetic approach for imaging synaptic inhibition. This approach is based on measuring intracellular chloride concentration ([Cl(-)](i)) with the fluorescent chloride indicator protein, Clomeleon. We first describe several different ways to express Clomeleon in selected populations of neurons in the mouse brain. These methods include targeted viral gene transfer, conditional expression controlled by Cre recombination, and transgenesis based on the neuron-specific promoter, thy1. Next, we evaluate the feasibility of using different lines of thy1::Clomeleon transgenic mice to image synaptic inhibition in several different brain regions: the hippocampus, the deep cerebellar nuclei (DC... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1873756 Sat, 11 Oct 2008 04:00:00 +0100 1873756 http://www.medworm.com/index.php?rid=1684171&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18679801%26dopt%3DAbstract Authors: Baker BJ, Mutoh H, Dimitrov D, Akemann W, Perron A, Iwamoto Y, Jin L, Cohen LB, Isacoff EY, Pieribone VA, Hughes T, Knöpfel T Imaging activity of neurons in intact brain tissue was conceived several decades ago and, after many years of development, voltage-sensitive dyes now offer the highest spatial and temporal resolution for imaging neuronal functions in the living brain. Further progress in this field is expected from the emergent development of genetically encoded fluorescent sensors of membrane potential. These fluorescent protein (FP) voltage sensors overcome the drawbacks of organic voltage sensitive dyes such as non-specificity of cell staining and the low accessibility of the dye to some cell types. In a transgenic animal, a genetically encoded sensor could in p... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1684171 Tue, 05 Aug 2008 04:00:00 +0100 1684171 http://www.medworm.com/index.php?rid=1680513&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18677566%26dopt%3DAbstract Authors: Gradinaru V, Thompson KR, Deisseroth K Temporally precise inhibition of distinct cell types in the intact nervous system has been enabled by the microbial halorhodopsin NpHR, a fast light-activated electrogenic Cl(-) pump. While neurons can be optically hyperpolarized and inhibited from firing action potentials at moderate NpHR expression levels, we have encountered challenges with pushing expression to extremely high levels, including apparent intracellular accumulations. We therefore sought to molecularly engineer NpHR to achieve strong expression without these cellular side effects. We found that high expression correlated with endoplasmic reticulum (ER) accumulation, and that under these conditions NpHR colocalized with ER proteins containing the KDEL ER retention sequence... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1680513 Sat, 02 Aug 2008 04:00:00 +0100 1680513 http://www.medworm.com/index.php?rid=1656356&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18654855%26dopt%3DAbstract Authors: Nakamura T, Aoki K, Matsuda M Genetically encoded probes based on Förster resonance energy transfer (FRET) enable us to decipher spatiotemporal information encoded in complex tissues such as the brain. Firstly, this review focuses on FRET probes wherein both the donor and acceptor are fluorescence proteins and are incorporated into a single molecule, i.e. unimolecular probes. Advantages of these probes lie in their easy loading into cells, the simple acquisition of FRET images, and the clear evaluation of data. Next, we introduce our recent study which encompasses FRET imaging and in silico simulation. In nerve growth factor-induced neurite outgrowth in PC12 cells, we found positive and negative signaling feedback loops. We propose that these feedback loops determine neur... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1656356 Fri, 25 Jul 2008 04:00:00 +0100 1656356 http://www.medworm.com/index.php?rid=1656355&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18654856%26dopt%3DAbstract Authors: Schoenenberger P, Grunditz A, Rose T, Oertner TG Over the past few years, the light-gated cation channel Channelrhodopsin-2 (ChR2) has seen a remarkable diversity of applications in neuroscience. However, commonly used wide-field illumination provides poor spatial selectivity for cell stimulation. We explored the potential of focal laser illumination to map photocurrents of individual neurons in sparsely transfected hippocampal slice cultures. Interestingly, the best spatial resolution of photocurrent induction was obtained at the lowest laser power. By adjusting the light intensity to a neuron's spike threshold, we were able to trigger action potentials with a spatial selectivity of less than 30 mum. Experiments with dissociated hippocampal cells suggested that the main facto... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1656355 Fri, 25 Jul 2008 04:00:00 +0100 1656355 http://www.medworm.com/index.php?rid=1598543&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18512154%26dopt%3DAbstract Authors: Murakoshi H, Lee SJ, Yasuda R Two-photon fluorescence lifetime imaging microscopy (TPFLIM) enables the quantitative measurements of fluorescence resonance energy transfer (FRET) in small subcellular compartments in light scattering tissue. We evaluated and optimized the FRET pair of mEGFP (monomeric EGFP with the A206K mutation) and REACh (non-radiative YFP variants) for TPFLIM. We characterized several mutants of REACh in terms of their "darkness," and their ability to act as a FRET acceptor for mEGFP in HeLa cells and hippocampal neurons. Since the commonly used monomeric mutation A206K increases the brightness of REACh, we introduced a different monomeric mutation (F223R) which does not affect the brightness. Also, we found that the folding efficiency of original REACh, as ... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1598543 Fri, 30 May 2008 04:00:00 +0100 1598543 http://www.medworm.com/index.php?rid=1598550&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18392728%26dopt%3DAbstract Authors: Hara C, Tateyama K, Akamatsu N, Imabayashi H, Karaki K, Nomura N, Okano H, Miyawaki A We have developed a device for pinpoint delivery of chemicals, proteins, and nucleic acids into cultured cells. The principle underlying the technique is the flow of molecules from the culture medium into cells through a rupture in the plasma membrane made by a needle puncture. DNA transfection is achieved by stabbing the needle tip into the nucleus. The CellBee device can be attached to any inverted microscope, and molecular delivery can be coupled with conventional live cell imaging. Because the position of the needle relative to the targeted cultured cells is computer-controlled, efficient delivery of molecules such as rhodamine into as many as 100 HeLa cells can be completed in 10 min. Mo... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1598550 Fri, 01 Dec 2006 05:00:00 +0100 1598550 http://www.medworm.com/index.php?rid=1598549&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18392729%26dopt%3DAbstract Authors: Jost B, Grabert J, Patz S, Schmidt M, Wahle P The distribution of mRNA for the rho2 subunit of the GABA(C) receptor is much broader in organotypic SC cultures than in vivo, suggesting that GABA(C) receptor expression is regulated by environmental factors. Electrophysiological recordings indicate that neurons in SC cultures have functional GABA(C) receptors, although these receptors exhibited smaller conductance than in vivo, probably due to increased rho2 subunit expression. Adding cortical input, treatment with various neuromodulators, and blocking neuronal activity with TTX failed to affect the expression of rho2 subunits. Electrophysiological recordings revealed the presence of spontaneous Ca(2+) currents in SC cultures and preventing these, by treatment with blockers of L-... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1598549 Fri, 01 Dec 2006 05:00:00 +0100 1598549 http://www.medworm.com/index.php?rid=1598548&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18392730%26dopt%3DAbstract Authors: Lundquist JJ, Dudek SM The extracellular signal-regulated kinases 1 and 2 (ERKs 1/2) are known to participate in regulating transcription in response to moderate depolarization, such as synaptic stimulation, but how the same active enzyme can differentially regulate distinct transcriptional programs induced with abnormal depolarization (high potassium) is unknown. We hypothesized that ERK1 or 2 accomplishes this differential nuclear response through close association with other proteins in stable complexes. In support of this hypothesis, we have found that immunoreactivity for an apparent high molecular weight complex containing phospho-ERK1 increased in response to synaptic stimulation, but decreased in response to high potassium; p-ERK immunoreactivity at 44/42 kDa increased... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1598548 Fri, 01 Dec 2006 05:00:00 +0100 1598548 http://www.medworm.com/index.php?rid=1598547&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18392731%26dopt%3DAbstract Authors: DeGiorgis JA, Galbraith JA, Dosemeci A, Chen X, Reese TS We compared the distribution of three scaffolding proteins, all belonging to a family of membrane-associated guanylate kinases, thought to have key roles in the organization of the postsynaptic density (PSD). Isolated PSDs readily adhered to treated glass coverslips where they were labeled with immunogold and rotary shadowed for analysis by EM. The distribution of proteins within individual PSDs were measured by counting and mapping individual immunogold particles. PSD-95, as previously described, is distributed evenly throughout the PSD. We find here that PSD-93 has a nearly identical distribution suggesting that PSD-95 and PSD-93 could perform similar roles. SAP97, in contrast, is concentrated near edges of cleft sides... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1598547 Fri, 01 Dec 2006 05:00:00 +0100 1598547 http://www.medworm.com/index.php?rid=1598546&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18398684%26dopt%3DAbstract We describe here a molecular genetic approach for imaging synaptic inhibition. The thy-1 promoter was used to express high levels of Clomeleon, a ratiometric fluorescent indicator for chloride ions, in discrete populations of neurons in the brains of transgenic mice. Clomeleon was functional after chronic expression and provided non-invasive readouts of intracellular chloride concentration ([Cl(-)](i)) in brain slices, allowing us to quantify age-dependent declines in resting [Cl(-)](i) during neuronal development. Activation of hippocampal interneurons caused [Cl(-)](i) to rise transiently in individual postsynaptic pyramidal neurons. [Cl(-)](i) increased in direct proportion to the amount of inhibitory transmission, with peak changes as large as 4 mM. Integrating responses over populatio... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1598546 Fri, 01 Dec 2006 05:00:00 +0100 1598546 http://www.medworm.com/index.php?rid=1598545&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18443910%26dopt%3DAbstract Authors: Augustine GJ PMID: 18443910 [PubMed - in process] (Source: Brain Cell Biology) Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1598545 Fri, 01 Dec 2006 05:00:00 +0100 1598545 http://www.medworm.com/index.php?rid=1598544&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18443911%26dopt%3DAbstract Authors: PMID: 18443911 [PubMed - in process] (Source: Brain Cell Biology) Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1598544 Fri, 01 Dec 2006 05:00:00 +0100 1598544 http://www.medworm.com/index.php?rid=1598557&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17957477%26dopt%3DAbstract Authors: Fdez E, Hilfiker S Synapsins are a multigene family of neuron-specific phosphoproteins and comprise the most abundant synaptic vesicle proteins. They have been proposed to tether synaptic vesicles to each other to maintain a reserve pool in the vicinity of the active zone. Such a role is supported by the observation that disruption of synapsin function leads to a depletion of the reserve pool of vesicles and an increase in synaptic depression. However, other functions for synapsins have been proposed as well, and there currently exists no coherent picture of how these abundant proteins modulate synaptic transmission. Here, we discuss novel insights into how synapsins may regulate neurotransmitter release. PMID: 17957477 [PubMed - indexed for MEDLINE] (Source: Brain Cell Bi... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1598557 Thu, 01 Jun 2006 04:00:00 +0100 1598557 http://www.medworm.com/index.php?rid=1598556&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17957478%26dopt%3DAbstract Authors: Tao-Cheng JH, Dosemeci A, Winters CA, Reese TS Phosphorylation of synapsin I by CaMKII has been reported to mobilize synaptic vesicles from the reserve pool. In the present study, the distributions of alpha-CaMKII and of synapsin I were compared in synaptic boutons of unstimulated and stimulated hippocampal neurons in culture by immunogold electron microscopy. CaMKII and synapsin I are located in separate domains in presynaptic terminals of unstimulated neurons. Label for alpha -CaMKII typically surrounds synaptic vesicle clusters and is absent from the inside of the cluster in control synapses. In contrast, intense labeling for synapsin I is found within the vesicle clusters. Following 2 minutes of depolarization in high K(+), synaptic vesicles decluster and CaMKII label disp... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1598556 Thu, 01 Jun 2006 04:00:00 +0100 1598556 http://www.medworm.com/index.php?rid=1598555&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17957479%26dopt%3DAbstract Authors: Villanueva M, Thornley K, Augustine GJ, Wightman RM We have assessed the role of synapsins in catecholamine release by comparing the properties of exocytosis in adrenal chromaffin cells from wild-type and synapsin triple knock-out (TKO) mice. Brief depolarizations led to a greater amount of catecholamine release in chromaffin cells from TKO mice in comparison to chromaffin cells from wild-type mice. This increase in catecholamine release was due to an increased number of exocytotic events, while the properties of individual quanta of released catecholamine were unchanged. Barium ions produced similar amounts of catecholamine release from TKO and wild-type chromaffin cells, suggesting that the reserve pool of chromaffin granules is unchanged following loss of synapsins. Because... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1598555 Thu, 01 Jun 2006 04:00:00 +0100 1598555 http://www.medworm.com/index.php?rid=1598554&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17957480%26dopt%3DAbstract Authors: Aloy EM, Weinmann O, Pot C, Kasper H, Dodd DA, Rülicke T, Rossi F, Schwab ME Formation and maintenance of a neuronal network is based on a balance between plasticity and stability of synaptic connections. Several molecules have been found to regulate the maintenance of excitatory synapses but nothing is known about the molecular mechanisms involved in synaptic stabilization versus disassembly at inhibitory synapses. Here, we demonstrate that Nogo-A, which is well known to be present in myelin and inhibit growth in the adult CNS, is present in inhibitory presynaptic terminals in cerebellar Purkinje cells at the time of Purkinje cell-Deep Cerebellar Nuclei (DCN) inhibitory synapse formation and is then downregulated during synapse maturation. We addressed the role of neuron... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1598554 Thu, 01 Jun 2006 04:00:00 +0100 1598554 http://www.medworm.com/index.php?rid=1598553&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17957481%26dopt%3DAbstract In this study, the expression of ECM-associated and cell-associated proteins such as the transmembrane CD44 adhesion molecule and neuro-glial proteoglycan 2 (NG2), a member of the chondroitin sulfate proteoglycan family, were evaluated during glioma progression, in vitro and in vivo, using a model of a highly invasive and aggressive intracerebral mouse G-26 glioma. We found a marked increase in CD44 and NG2 expression in brain tissue containing glioma. The glioma levels of these proteins gradually increased over time to reach 3-15 times the levels in the contralateral control. NG2 and CD44 expression paralleled progression of the glioma, being higher on days 14 and 21 than on day 2 post-glioma implant. In addition, when invading glioma crossed the midline in the advanced tumor stage, level... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1598553 Thu, 01 Jun 2006 04:00:00 +0100 1598553 http://www.medworm.com/index.php?rid=1598552&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17957482%26dopt%3DAbstract Authors: Chin JH, Tse FW, Harris K, Jhamandas JH Beta-amyloid, a 39-43 amino acid peptide, may exert its biological effects via neuronal nicotinic acetylcholine receptors. Using the ratiometric dye, fura-2, we examined the effect of soluble beta-amyloid(1-42) on the concentration of intracellular Ca(2+) ([Ca(2+)](i)) in acutely dissociated rat basal forebrain neurons. Focal applications of nicotine (0.5-20 mM), evoked dose-dependent increases in intracellular [Ca(2+)](i) that were mediated by the entry of extracellular Ca(2+) via nicotinic acetylcholine receptors, and the release of intracellular Ca(2+) from stores. With repeated nicotine challenges, the nicotinic responses were potentiated by 98 +/- 12% (P < 0.05) while beta-amyloid(1-42)(100 nM) was present for approximately 5 min... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1598552 Thu, 01 Jun 2006 04:00:00 +0100 1598552 http://www.medworm.com/index.php?rid=1598551&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17957483%26dopt%3DAbstract Authors: Verderio C, Bianco F, Blanchard MP, Bergami M, Canossa M, Scarfone E, Matteoli M It is now well-established that an active cross-talk occurs between neurons and glial cells, in the adult as well as in the developing and regenerating nervous systems. These functional interactions not only actively modulate synaptic transmission, but also support neuronal growth and differentiation. We have investigated the possible existence of a reciprocal interaction between inner ear vestibular neurons and Schwann cells maintained in primary cultures. We show that ATP released by the extending vestibular axons elevates intracellular calcium levels within Schwann cells. Purinergic activation of the Schwann P2X(7) receptor induces the release of neurotrophin BDNF, which occurs via a regulated,... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1598551 Thu, 01 Jun 2006 04:00:00 +0100 1598551 http://www.medworm.com/index.php?rid=1598564&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17940909%26dopt%3DAbstract Authors: Bennett MV, Pereda A Electrical transmission in the mammalian brain is now well established. A new study by Thomson and colleagues elegantly demonstrates coupling between CA1 hippocampal pyramidal cells, which is far more common than previously supposed. Although the history of coupling is extensive, doubt, predjudice, and technical issues long kept it from wide acceptance. Here "spikelets" or "fast prepotentials" are found when two cells are coupled and in this situation result from electrical transmission of impulses from one coupled cell to the other. Interesting questions remain as to whether connexin or pannexin gap junctions serve as the molecular substrate of transmission, and the role of electrical transmission in hippocampal physiology is uncertain. Increased coupling... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1598564 Wed, 01 Feb 2006 05:00:00 +0100 1598564 http://www.medworm.com/index.php?rid=1598563&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17940910%26dopt%3DAbstract Authors: Mercer A, Bannister AP, Thomson AM Recently, intense interest has focussed on electrical coupling between interneurones in cortical regions and their contributions towards oscillatory network activity. Despite mounting circumstantial evidence that pyramidal cells are also coupled, the paucity of direct evidence has made this controversial. Dual intracellular recordings from pairs of cortical and hippocampal pyramids demonstrated strong, but sparse coupling. Approximately 70% of CA1 pyramids close to the stratum radiatum border were coupled to another pyramid, but only to one or two of their very closest neighbours. On average 25% of the steady state and 10% of the peak action potential voltage change in one cell transferred to the other, supporting synchrony and promoting burs... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1598563 Wed, 01 Feb 2006 05:00:00 +0100 1598563 http://www.medworm.com/index.php?rid=1598562&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17940911%26dopt%3DAbstract Authors: Horton AC, Yi JJ, Ehlers MD Pyramidal neurons of the hippocampus and cortex have polarized dendritic arbors, but little is known about the cellular mechanisms distinguishing apical and basal dendrites. We used morphometric analysis and time lapse imaging of cultured hippocampal neurons to show that glutamatergic neurons develop progressive dendritic asymmetry in the absence of polarized extrinsic cues. Thus, pyramidal neurons have a cellular program for polarized dendrite growth independent of tissue microenvironment. PMID: 17940911 [PubMed - indexed for MEDLINE] (Source: Brain Cell Biology) Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1598562 Wed, 01 Feb 2006 05:00:00 +0100 1598562 http://www.medworm.com/index.php?rid=1598561&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17940912%26dopt%3DAbstract Authors: Dehmelt L, Nalbant P, Steffen W, Halpain S A key event in neurite initiation is the accumulation of microtubule bundles at the neuron periphery. We hypothesized that such bundled microtubules may generate a force at the plasma membrane that facilitates neurite initiation. To test this idea we observed the behavior of microtubule bundles that were induced by the microtubule-associated protein MAP2c. Endogenous MAP2c contributes to neurite initiation in primary neurons, and exogeneous MAP2c is sufficient to induce neurites in Neuro-2a cells. We performed nocodazol washout experiments in primary neurons, Neuro-2a cells and COS-7 cells to investigate the underlying mechanism. During nocodazol washout, small microtubule bundles formed rapidly in the cytoplasm and immediately began ... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1598561 Wed, 01 Feb 2006 05:00:00 +0100 1598561 http://www.medworm.com/index.php?rid=1598560&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17940913%26dopt%3DAbstract Authors: Malkinson G, Fridman ZM, Kamber D, Dormann A, Shapira E, Spira ME Varicosities are ubiquitous neuronal structures that appear as local swellings along neurites of invertebrate and vertebrate neurons. Surprisingly little is known about their cell biology. We use here cultured Aplysia neurons and demonstrate that varicosities are motile compartments that contain large clusters of organelles. The content of varicosities propagate along neurites within the plasma membrane "sleeve", split and merge, or wobble in place. Confocal imaging, retrospective immunolabeling, electron microscopy and pharmacological perturbations reveal that the motility of the varicosities' organelle content occurs in concert with an actin scaffold and is generated by actomyosin motors. Despite the motility ... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1598560 Wed, 01 Feb 2006 05:00:00 +0100 1598560 http://www.medworm.com/index.php?rid=1598559&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17940914%26dopt%3DAbstract Authors: Kolikova J, Afzalov R, Giniatullina A, Surin A, Giniatullin R, Khiroug L Growing evidence suggests that astrocytes are the active partners of neurons in many brain functions. Astrocytic mitochondria are highly motile organelles which regulate the temporal and spatial patterns of Ca( 2+ ) dynamics, in addition to being a major source of ATP and reactive oxygen species. Previous studies have shown that mitochondria translocate to endoplasmic reticulum during Ca( 2+ ) release from internal stores, but whether a similar spatial interaction between mitochondria and plasma membrane occurs is not known. Using total internal reflection fluorescence (TIRF) microscopy we show that a fraction of mitochondria became trapped near the plasma membrane of cultured hippocampal astrocytes durin... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1598559 Wed, 01 Feb 2006 05:00:00 +0100 1598559 http://www.medworm.com/index.php?rid=1598558&cid=s_37627_171_f&fid=37627&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D17940915%26dopt%3DAbstract Authors: Bosman LW, Hartmann J, Barski JJ, Lepier A, Noll-Hussong M, Reichardt LF, Konnerth A The receptor tyrosine kinase TrkB and its ligands, brain-derived neurotrophic factor (BDNF) and neurotrophin-4/5 (NT-4/5), are critically important for growth, survival and activity-dependent synaptic strengthening in the central nervous system. These TrkB-mediated actions occur in a highly cell-type specific manner. Here we report that cerebellar Purkinje cells, which are richly endowed with TrkB receptors, develop a normal morphology in trkB-deficient mice. Thus, in contrast to other types of neurons, Purkinje cells do not need TrkB for dendritic growth and spine formation. Instead, we find a moderate delay in the maturation of GABAergic synapses and, more importantly, an abnormal multiple c... Brain Cell Biology journals http://www.medworm.com/rss/comments.php?id=1598558 Wed, 01 Feb 2006 05:00:00 +0100 1598558