Coordinated multivesicular release at a mammalian ribbon synapse

Nat Neurosci. 2004 Aug;7(8):826-33. doi: 10.1038/nn1280. Epub 2004 Jul 4.

Abstract

Traditional models of synaptic transmission hold that release sites within an active zone operate independently. Although the release of multiple vesicles (multivesicular release; MVR) from single active zones occurs at some central synapses, MVR is not thought to require coordination among release sites. Ribbon synapses seem to be optimized to release many vesicles over an extended period, but the dynamics of MVR at ribbon synapses is unknown. We examined MVR at a ribbon synapse in a retinal slice preparation using paired recordings from presynaptic rod bipolar and postsynaptic AII amacrine cells. When evoked release was highly desynchronized, discrete postsynaptic events were larger than quantal miniature excitatory postsynaptic currents (mEPSCs) but had the same time course. The amplitude of these multiquantal mEPSCs, which seem to arise from the essentially simultaneous release of multiple vesicles, was reduced by lowering release probability. The release synchrony reflected in these multivesicular events suggests that release within an active zone is coordinated during MVR.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cytoplasmic Vesicles / drug effects
  • Cytoplasmic Vesicles / physiology*
  • Excitatory Amino Acid Antagonists / pharmacology
  • Excitatory Postsynaptic Potentials
  • Exocytosis / physiology*
  • Immunohistochemistry
  • Monte Carlo Method
  • Organ Culture Techniques
  • Patch-Clamp Techniques
  • Rats
  • Retina / drug effects
  • Retina / physiology*
  • Synapses / drug effects
  • Synapses / physiology*
  • Synaptic Transmission / drug effects
  • Synaptic Transmission / physiology

Substances

  • Excitatory Amino Acid Antagonists