Physical determinants of vesicle mobility and supply at a central synapse

Jason Seth Rothman, Laszlo Kocsis, Etienne Herzog, Zoltan Nusser, Robin Angus Silver

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16 Citations (Scopus)

Abstract

Encoding continuous sensory variables requires sustained synaptic signalling. At several sensory synapses, rapid vesicle supply is achieved via highly mobile vesicles and specialized ribbon structures, but how this is achieved at central synapses without ribbons is unclear. Here we examine vesicle mobility at excitatory cerebellar mossy fibre synapses which sustain transmission over a broad frequency bandwidth. Fluorescent recovery after photobleaching in slices from VGLUT1Venus knock-in mice reveal 75% of VGLUT1-containing vesicles have a high mobility, comparable to that at ribbon synapses. Experimentally constrained models establish hydrodynamic interactions and vesicle collisions are major determinants of vesicle mobility in crowded presynaptic terminals. Moreover, models incorporating 3D reconstructions of vesicle clouds near active zones (AZs) predict the measured releasable pool size and replenishment rate from the reserve pool. They also show that while vesicle reloading at AZs is not diffusion-limited at the onset of release, diffusion limits vesicle reloading during sustained high-frequency signalling.

Original languageEnglish
Article numbere15133
JournaleLife
Volume5
Issue numberAUGUST
DOIs
Publication statusPublished - Aug 19 2016

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ASJC Scopus subject areas

  • Neuroscience(all)
  • Immunology and Microbiology(all)
  • Biochemistry, Genetics and Molecular Biology(all)

Cite this

Rothman, J. S., Kocsis, L., Herzog, E., Nusser, Z., & Silver, R. A. (2016). Physical determinants of vesicle mobility and supply at a central synapse. eLife, 5(AUGUST), [e15133]. https://doi.org/10.7554/eLife.15133