Calmodulin mediates rapid recruitment of fast-releasing synaptic vesicles at a calyx-type synapse

Neuron. 2001 Dec 20;32(6):1119-31. doi: 10.1016/s0896-6273(01)00543-8.


In many synapses, depletion and recruitment of releasable synaptic vesicles contribute to use-dependent synaptic depression and recovery. Recently it has been shown that high-frequency presynaptic stimulation enhances recovery from depression, which may be mediated by Ca2+. We addressed this issue by measuring quantal release rates at the calyx of Held synapse and found that transmission is mediated by a heterogeneous population of vesicles, with one subset releasing rapidly and recovering slowly and another one releasing reluctantly and recovering rapidly. Ca2+ promotes refilling of the rapidly releasing synaptic vesicle pool and calmodulin inhibitors block this effect. We propose that calmodulin-dependent refilling supports recovery from synaptic depression during high-frequency trains in concert with rapid recovery of the slowly releasing vesicles.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials / physiology
  • Animals
  • Brain Stem / physiology
  • Calcium / metabolism
  • Calmodulin / metabolism*
  • Chelating Agents / pharmacology
  • Egtazic Acid / pharmacology
  • Excitatory Postsynaptic Potentials / drug effects
  • Excitatory Postsynaptic Potentials / physiology
  • Rats
  • Rats, Wistar
  • Synaptic Transmission / physiology*
  • Synaptic Vesicles / metabolism*


  • Calmodulin
  • Chelating Agents
  • Egtazic Acid
  • Calcium