Calcium dependence of exo- and endocytotic coupling at a glutamatergic synapse

Neuron. 2009 Jul 30;63(2):216-29. doi: 10.1016/j.neuron.2009.06.010.

Abstract

The mechanism coupling exocytosis and endocytosis remains to be elucidated at central synapses. Here, we show that the mechanism linking these two processes is dependent on microdomain-[Ca2+](i) similar to that which triggers exocytosis, as well as the exocytotic protein synaptobrevin/VAMP. Furthermore, block of endocytosis has a limited, retrograde action on exocytosis, delaying recruitment of release-ready vesicles and enhancing short-term depression. This effect sets in so rapidly that it cannot be explained by the nonavailability of recycled vesicles. Rather, we postulate that perturbation of a step linking exocytosis and endocytosis temporarily prevents new vesicles from docking at specialized sites for exocytosis.

MeSH terms

  • Animals
  • Brain Stem / cytology
  • Calcium / metabolism*
  • Calcium Signaling / physiology*
  • Dynamins / metabolism
  • Endocytosis / physiology*
  • Excitatory Postsynaptic Potentials / physiology
  • Exocytosis / physiology*
  • Glutamic Acid / metabolism*
  • Neurons / metabolism*
  • Organ Culture Techniques
  • Presynaptic Terminals / metabolism
  • R-SNARE Proteins / metabolism
  • Rats
  • Rats, Wistar
  • Synapses / metabolism*
  • Synaptic Transmission / physiology

Substances

  • R-SNARE Proteins
  • Glutamic Acid
  • Dynamins
  • Calcium