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Ribbon synapse

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https://www.readbyqxmd.com/read/28921532/the-morphological-characterization-of-orientation-biased-displaced-large-field-ganglion-cells-in-the-central-part-of-goldfish-retina
#1
Hideo Hoshi, Fumi Sato
The vertebrate retina has about 30 subtypes of ganglion cells. Each ganglion cell receives synaptic inputs from specific types of bipolar and amacrine cells ramifying at the same depth of the inner plexiform layer (IPL), each of which is thought to process a specific aspect of visual information. Here, we identified one type of displaced ganglion cell in the goldfish retina which had a large and elongated dendritic field. As a population, all of these ganglion cells were oriented in the horizontal axis and perpendicular to the dorsal-ventral axis of the goldfish eye in the central part of retina...
September 18, 2017: Journal of Comparative Neurology
https://www.readbyqxmd.com/read/28915323/hair-cell-transduction-tuning-and-synaptic-transmission-in-the-mammalian-cochlea
#2
Robert Fettiplace
Sound pressure fluctuations striking the ear are conveyed to the cochlea, where they vibrate the basilar membrane on which sit hair cells, the mechanoreceptors of the inner ear. Recordings of hair cell electrical responses have shown that they transduce sound via submicrometer deflections of their hair bundles, which are arrays of interconnected stereocilia containing the mechanoelectrical transducer (MET) channels. MET channels are activated by tension in extracellular tip links bridging adjacent stereocilia, and they can respond within microseconds to nanometer displacements of the bundle, facilitated by multiple processes of Ca2+-dependent adaptation...
September 12, 2017: Comprehensive Physiology
https://www.readbyqxmd.com/read/28874522/efficient-stimulus-secretion-coupling-at-ribbon-synapses-requires-rim-binding-protein-tethering-of-l-type-ca-2-channels
#3
Fujun Luo, Xinran Liu, Thomas C Südhof, Claudio Acuna
Fast neurotransmitter release from ribbon synapses via Ca(2+)-triggered exocytosis requires tight coupling of L-type Ca(2+) channels to release-ready synaptic vesicles at the presynaptic active zone, which is localized at the base of the ribbon. Here, we used genetic, electrophysiological, and ultrastructural analyses to probe the architecture of ribbon synapses by perturbing the function of RIM-binding proteins (RBPs) as central active-zone scaffolding molecules. We found that genetic deletion of RBP1 and RBP2 did not impair synapse ultrastructure of ribbon-type synapses formed between rod bipolar cells (RBCs) and amacrine type-2 (AII) cells in the mouse retina but dramatically reduced the density of presynaptic Ca(2+) channels, decreased and desynchronized evoked neurotransmitter release, and rendered evoked and spontaneous neurotransmitter release sensitive to the slow Ca(2+) buffer EGTA...
September 5, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28863864/two-pools-of-vesicles-associated-with-synaptic-ribbons-are-molecularly-prepared-for-release
#4
Proleta Datta, Jared Gilliam, Wallace B Thoreson, Roger Janz, Ruth Heidelberger
Neurons that form ribbon-style synapses are specialized for continuous exocytosis. To this end, their synaptic terminals contain numerous synaptic vesicles, some of which are ribbon associated, that have difference susceptibilities for undergoing Ca(2+)-dependent exocytosis. In this study, we probed the relationship between previously defined vesicle populations and determined their fusion competency with respect to SNARE complex formation. We found that both the rapidly releasing vesicle pool and the releasable vesicle pool of the retinal bipolar cell are situated at the ribbon-style active zones, where they functionally interact...
August 29, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28827351/mechanisms-of-synaptic-depression-at-the-hair-cell-ribbon-synapse-that-support-auditory-nerve-function
#5
Juan D Goutman
Inner hair cells (IHCs) in the cochlea are the mammalian phono-receptors, transducing sound energy into graded changes in membrane potentials, the so called "receptor potentials." Ribbon synapses between IHCs and auditory nerve neurons are responsible for converting receptor potentials into spike rates. The characteristics of auditory nerve responses to sound have been described extensively. For instance, persistent acoustic stimulation produces sensory adaptation, which is revealed as a reduction in neuronal spike rate with time constants in the range of milliseconds to seconds...
August 21, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28821654/wnt9a-can-influence-cell-fates-and-neural-connectivity-across-the-radial-axis-of-the-developing-cochlea
#6
Vidhya Munnamalai, Ulrike J Sienknecht, R Keith Duncan, M Katie Scott, Ankita Thawani, Kristen N Fantetti, Nadia M Atallah, Deborah J Biesemeier, Kuhn H Song, Kirsten Luethy, Eric Traub, Donna M Fekete
Vertebrate hearing organs manifest cellular asymmetries across the radial axis that underlie afferent versus efferent circuits between the inner ear and the brain. Thus, understanding the molecular control of patterning across this axis has important functional implications. Radial axis patterning begins before the cells become postmitotic, and is likely linked to the onset of asymmetric expression of secreted factors adjacent to the sensory primordium. This study explores one such asymmetrically-expressed gene, Wnt9a, that becomes restricted to the neural edge of the avian auditory organ, the basilar papilla, by embryonic day (E) 5...
August 14, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28790889/the-calcineurin-binding-activity-dependent-splice-variant-dynamin1xb-is-highly-enriched-in-synapses-in-various-regions-of-the-central-nervous-system
#7
Marie-Lisa Eich, Ekta Dembla, Silke Wahl, Mayur Dembla, Karin Schwarz, Frank Schmitz
In the present study, we generated and characterized a splice site-specific monoclonal antibody that selectively detects the calcineurin-binding dynamin1 splice variant dynamin1xb. Calcineurin is a Ca(2+)-regulated phosphatase that enhances dynamin1 activity and is an important Ca(2+)-sensing mediator of homeostatic synaptic plasticity in neurons. Using this dynamin1xb-specific antibody, we found dynamin1xb highly enriched in synapses of all analyzed brain regions. In photoreceptor ribbon synapses, dynamin1xb was enriched in close vicinity to the synaptic ribbon in a manner indicative of a peri-active zone immunolabeling...
2017: Frontiers in Molecular Neuroscience
https://www.readbyqxmd.com/read/28744553/brag2a-a-guanine-nucleotide-exchange-factor-for-arf6-is-a-component-of-the-dystrophin-associated-glycoprotein-complex-at-the-photoreceptor-terminal
#8
Hiroyuki Sakagami, Osamu Katsumata, Yoshinobu Hara, Toshikuni Sasaoka, Masahiro Fukaya
Purpose: Mutations in genes encoding the dystrophin-associated glycoprotein complex (DGC) can cause muscular dystrophy and disturb synaptic transmission in the photoreceptor ribbon synapse. However, the molecular composition and specific functions of the photoreceptor DGC remain unknown. Brefeldin A-resistant Arf-GEF 2 (BRAG2), also known as IQSEC1, is a guanine nucleotide exchange factor for ADP-ribosylation factor 6 (Arf6), a critical GTPase that regulates endosomal trafficking and actin cytoskeleton remodeling...
July 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28703809/epigallocatechin-3-gallate-a-prototypic-chemopreventative-agent-for-protection-against-cisplatin-based-ototoxicity
#9
Vikrant Borse, Raheem F H Al Aameri, Kelly Sheehan, Sandeep Sheth, Tejbeer Kaur, Debashree Mukherjea, Srinivasan Tupal, Michelle Lowy, Sumana Ghosh, Asmita Dhukhwa, Puspanjali Bhatta, Leonard P Rybak, Vickram Ramkumar
Cisplatin-induced ototoxicity is one of the major factors limiting cisplatin chemotherapy. Ototoxicity results from damage to outer hair cells (OHCs) and other regions of the cochlea. At the cellular level, cisplatin increases reactive oxygen species (ROS) leading to cochlear inflammation and apoptosis. Thus, ideal otoprotective drugs should target oxidative stress and inflammatory mechanisms without interfering with cisplatin's chemotherapeutic efficacy. In this study, we show that epigallocatechin-3-gallate (EGCG) is a prototypic agent exhibiting these properties of an effect otoprotective agent...
July 13, 2017: Cell Death & Disease
https://www.readbyqxmd.com/read/28701482/analysis-of-rim-expression-and-function-at-mouse-photoreceptor-ribbon-synapses
#10
Martina Löhner, Norbert Babai, Tanja Müller, Kaspar Gierke, Jenny Atorf, Anneka Joachimsthaler, Angela Peukert, Henrik Martens, Andreas Feigenspan, Jan Kremers, Susanne Schoch, Johann Helmut Brandstätter, Hanna Regus-Leidig
RAB3A-interacting molecule (RIM) proteins are important regulators of transmitter release from active zones. At conventional chemical synapses, RIMs contribute substantially to vesicle priming and docking and their loss reduces the readily releasable pool of synaptic vesicles by up to 75%. The priming function of RIMs is mediated via the formation of a tripartite complex with Munc13 and RAB3A, which brings synaptic vesicles in close proximity to Ca(2+) channels and the fusion site and activates Munc13. We reported previously that, at mouse photoreceptor ribbon synapses, vesicle priming is Munc13 independent...
August 16, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28642685/rab-interacting-molecules-2-and-3-directly-interact-with-the-pore-forming-cav1-3-ca-2-channel-subunit-and-promote-its-membrane-expression
#11
Maria M Picher, Ana-Maria Oprişoreanu, SangYong Jung, Katrin Michel, Susanne Schoch, Tobias Moser
Rab interacting molecules (RIMs) are multi-domain proteins that positively regulate the number of Ca(2+) channels at the presynaptic active zone (AZ). Several molecular mechanisms have been demonstrated for RIM-binding to components of the presynaptic Ca(2+) channel complex, the key signaling element at the AZ. Here, we report an interaction of the C2B domain of RIM2α and RIM3γ with the C-terminus of the pore-forming α-subunit of CaV1.3 channels (CaV1.3α1), which mediate stimulus-secretion coupling at the ribbon synapses of cochlear inner hair cells (IHCs)...
2017: Frontiers in Cellular Neuroscience
https://www.readbyqxmd.com/read/28641988/wavy-multistratified-amacrine-cells-in-the-monkey-retina-contain-immunoreactive-secretoneurin
#12
Andrea S Bordt, Ye Long, Nobuo Kouyama, Elizabeth S Yamada, Jens Hannibal, David W Marshak
The goals of this study were to describe the morphology, neurotransmitter content and synaptic connections of neurons in primate retinas that contain the neuropeptide secretoneurin. Amacrine cells were labeled with antibodies to secretoneurin in macaque and baboon retinas. Their processes formed three distinct plexuses in the inner plexiform layer: one in the outermost stratum, one in the center and one in the innermost stratum. In light microscopic double immunolabeling experiments, GABA was colocalized with secretoneurin in these cells, but glycine transporter 1 and Substance P were not...
August 2017: Peptides
https://www.readbyqxmd.com/read/28612046/shaping-of-signal-transmission-at-the-photoreceptor-synapse-by-eaat2-glutamate-transporters
#13
Stephanie Niklaus, Lucia Cadetti, Colette M Vom Berg-Maurer, André Lehnherr, Adriana L Hotz, Ian C Forster, Matthias Gesemann, Stephan C F Neuhauss
Photoreceptor ribbon synapses tonically release glutamate. To ensure efficient signal transmission and prevent glutamate toxicity, a highly efficient glutamate removal system provided by members of the SLC1 gene family is required. By using a combination of biophysical and in vivo studies, we elucidate the role of excitatory amino acid transporter 2 (EAAT2) proteins in synaptic glutamate homeostasis at the zebrafish photoreceptor synapse. The main glutamate sink is provided by the glial EAAT2a, reflected by reduced electroretinographic responses in EAAT2a-depleted larvae...
May 2017: ENeuro
https://www.readbyqxmd.com/read/28576729/afferent-synaptogenesis-between-ectopic-hair-cell-like-cells-and-neurites-of-spiral-ganglion-induced-by-atoh1-in-mammals-in-vitro
#14
Wen-Wei Luo, Rui Ma, Xiang Cheng, Xiao-Yu Yang, Zhao Han, Dong-Dong Ren, Ping Chen, Fang-Lu Chi, Juan-Mei Yang
Newly formed ectopic hair-cell-like cells (EHCLCs) induced by overexpression of atonal homolog 1 (Atoh1) in vitro were found to possess features of endogenous hair cells (HCs) in previous reports and in the present study. However, limited information is available regarding whether EHCLCs and native spiral ganglion neurons (SGNs) form afferent synapses, which are important for the restoration of hearing. In the current study, we focused on the afferent synaptogenesis between EHCLCs and SGN-derived dendrites...
May 31, 2017: Neuroscience
https://www.readbyqxmd.com/read/28546313/enlargement-of-ribbons-in-zebrafish-hair-cells-increases-calcium-currents-but-disrupts-afferent-spontaneous-activity-and-timing-of-stimulus-onset
#15
Lavinia Sheets, Xinyi J He, Jennifer Olt, Mary Schreck, Ronald S Petralia, Ya-Xian Wang, Qiuxiang Zhang, Alisha Beirl, Teresa Nicolson, Walter Marcotti, Josef G Trapani, Katie S Kindt
In sensory hair cells of auditory and vestibular organs, the ribbon synapse is required for the precise encoding of a wide range of complex stimuli. Hair cells have a unique presynaptic structure, the synaptic ribbon, which organizes both synaptic vesicles and calcium channels at the active zone. Previous work has shown that hair-cell ribbon size is correlated with differences in postsynaptic activity. However, additional variability in postsynapse size presents a challenge to determining the specific role of ribbon size in sensory encoding...
June 28, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28539424/ca-2-permeable-ampars-mediate-glutamatergic-transmission-and-excitotoxic-damage-at-the-hair-cell-ribbon-synapse
#16
Joy Y Sebe, Soyoun Cho, Lavinia Sheets, Mark A Rutherford, Henrique von Gersdorff, David W Raible
We report functional and structural evidence for GluA2-lacking Ca(2+)-permeable AMPARs (CP-AMPARs) at the mature hair cell ribbon synapse. By using the methodological advantages of three species (of either sex), we demonstrate that CP-AMPARs are present at the hair cell synapse in an evolutionarily conserved manner. Via a combination of in vivo electrophysiological and Ca(2+) imaging approaches in the larval zebrafish, we show that hair cell stimulation leads to robust Ca(2+) influx into afferent terminals...
June 21, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28438658/antioxidants-reduce-neurodegeneration-and-accumulation-of-pathologic-tau-proteins-in-the-auditory-system-after-blast-exposure
#17
Xiaoping Du, Matthew B West, Qunfeng Cai, Weihua Cheng, Donald L Ewert, Wei Li, Robert A Floyd, Richard D Kopke
Cochlear neurodegeneration commonly accompanies hair cell loss resulting from aging, ototoxicity, or exposures to intense noise or blast overpressures. However, the precise pathophysiological mechanisms that drive this degenerative response have not been fully elucidated. Our laboratory previously demonstrated that non-transgenic rats exposed to blast overpressures exhibited marked somatic accumulation of neurotoxic variants of the microtubule-associated protein, Tau, in the hippocampus. In the present study, we extended these analyses to examine neurodegeneration and pathologic Tau accumulation in the auditory system in response to blast exposure and evaluated the potential therapeutic efficacy of antioxidants on short-circuiting this pathological process...
April 22, 2017: Free Radical Biology & Medicine
https://www.readbyqxmd.com/read/28378516/how-do-horizontal-cells-talk-to-cone-photoreceptors-different-levels-of-complexity-at-the-cone-horizontal-cell-synapse
#18
Camille A Chapot, Thomas Euler, Timm Schubert
The first synapse of the retina plays a fundamental role in the visual system. Due to its importance, it is critical that it encodes information from the outside world with the greatest accuracy and precision possible. Cone photoreceptor axon terminals contain many individual synaptic sites, each represented by a presynaptic structure called a 'ribbon'. These synapses are both highly sophisticated and conserved. Each ribbon relays the light signal to one ON cone bipolar cell and several OFF cone bipolar cells, while two dendritic processes from a GABAergic interneuron, the horizontal cell, modulate the cone output via parallel feedback mechanisms...
August 15, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28363980/a-presynaptic-group-iii-mglur-recruits-g%C3%AE-%C3%AE-snare-interactions-to-inhibit-synaptic-transmission-by-cone-photoreceptors-in-the-vertebrate-retina
#19
Matthew J Van Hook, Norbert Babai, Zack Zurawski, Yun Young Yim, Heidi E Hamm, Wallace B Thoreson
G-protein βγ subunits (Gβγ) interact with presynaptic proteins and regulate neurotransmitter release downstream of Ca(2+) influx. To accomplish their roles in sensory signaling, photoreceptor synapses use specialized presynaptic proteins that support neurotransmission at active zone structures known as ribbons. While several G-protein coupled receptors (GPCRs) influence synaptic transmission at ribbon synapses of cones and other retinal neurons, it is unknown whether Gβγ contributes to these effects. We tested whether activation of one particular GPCR, a metabotropic glutamate receptor (mGluR), can reduce cone synaptic transmission via Gβγ in tiger salamander retinas...
April 26, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28346141/insights-into-electrosensory-organ-development-physiology-and-evolution-from-a-lateral-line-enriched-transcriptome
#20
Melinda S Modrell, Mike Lyne, Adrian R Carr, Harold H Zakon, David Buckley, Alexander S Campbell, Marcus C Davis, Gos Micklem, Clare Vh Baker
The anamniote lateral line system, comprising mechanosensory neuromasts and electrosensory ampullary organs, is a useful model for investigating the developmental and evolutionary diversification of different organs and cell types. Zebrafish neuromast development is increasingly well understood, but neither zebrafish nor Xenopus is electroreceptive and our molecular understanding of ampullary organ development is rudimentary. We have used RNA-seq to generate a lateral line-enriched gene-set from late-larval paddlefish (Polyodon spathula)...
March 27, 2017: ELife
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