Journal article
Ca2+ channel to synaptic vesicle distance accounts for the readily releasable pool kinetics at a functionally mature auditory synapse
The Journal of neuroscience, Vol.35(5), pp.2083-2100
02/04/2015
DOI: 10.1523/JNEUROSCI.2753-14.2015
PMID: 25653365
Abstract
Precise regulation of synaptic vesicle (SV) release at the calyx of Held is critical for auditory processing. At the prehearing calyx of Held, synchronous and asynchronous release is mediated by fast and slow releasing SVs within the readily releasable pool (RRP). However, the posthearing calyx has dramatically different release properties. Whether developmental alterations in RRP properties contribute to the accelerated release time course found in posthearing calyces is not known. To study these questions, we performed paired patch-clamp recordings, deconvolution analysis, and numerical simulations of buffered Ca(2+) diffusion and SV release in postnatal day (P) 16-19 mouse calyces, as their release properties resemble mature calyces of Held. We found the P16-P19 calyx RRP consists of two pools: a fast pool (τ ≤ 0.9 ms) and slow pool (τ ∼4 ms), in which release kinetics and relative composition of the two pools were unaffected by 5 mm EGTA. Simulations of SV release from the RRP revealed that two populations of SVs were necessary to reproduce the experimental release rates: (1) SVs located close (∼5-25 nm) and (2) more distal (25-100 nm) to VGCC clusters. This positional coupling was confirmed by experiments showing 20 mm EGTA preferentially blocked distally coupled SVs. Lowering external [Ca(2+)] to in vivo levels reduced only the fraction SVs released from the fast pool. Therefore, we conclude that a dominant parameter regulating the mature calyx RRP release kinetics is the distance between SVs and VGCC clusters.
Details
- Title: Subtitle
- Ca2+ channel to synaptic vesicle distance accounts for the readily releasable pool kinetics at a functionally mature auditory synapse
- Creators
- Zuxin Chen - Research Group Molecular Mechanisms of Synaptic Function, Max Planck Florida Institute, Jupiter, Florida 33458Brati Das - Research Group Molecular Mechanisms of Synaptic Function, Max Planck Florida Institute, Jupiter, Florida 33458, Integrative Program in Biology and Neuroscience, Florida Atlantic University, Jupiter, Florida 33458Yukihiro Nakamura - Laboratory of Dynamic Neuronal Imaging, Institut Pasteur, 75724 Paris Cedex 15, France, and CNRS UMR 3571, 75724 Paris Cedex 15, FranceDavid A DiGregorio - Laboratory of Dynamic Neuronal Imaging, Institut Pasteur, 75724 Paris Cedex 15, France, and CNRS UMR 3571, 75724 Paris Cedex 15, FranceSamuel M Young Jr - Research Group Molecular Mechanisms of Synaptic Function, Max Planck Florida Institute, Jupiter, Florida 33458, sam.young@mpfi.org
- Resource Type
- Journal article
- Publication Details
- The Journal of neuroscience, Vol.35(5), pp.2083-2100
- Publisher
- United States
- DOI
- 10.1523/JNEUROSCI.2753-14.2015
- PMID
- 25653365
- ISSN
- 0270-6474
- eISSN
- 1529-2401
- Language
- English
- Date published
- 02/04/2015
- Academic Unit
- Anatomy and Cell Biology; Iowa Neuroscience Institute; Otolaryngology
- Record Identifier
- 9984025475602771
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