Differential regulation of exocytosis by calcium and CAPS in semi-intact synaptosomes

Neuron. 1998 Jul;21(1):147-54. doi: 10.1016/s0896-6273(00)80522-x.


Using a novel approach to measure exocytosis in vitro from semi-intact synaptosomes, we establish that the Ca2+-dependent release of glutamate requires cytosolic factors for mobilization from the reserve pool. The cytosolic activity for glutamate release was not satisfied by CAPS, a soluble component required for norepinephrine (NE) release. Moreover, the CAPS-independent glutamate release from synaptic vesicles (SVs) was 200-fold less sensitive to Ca2+ than that required for dense core vesicles (DCVs). The differential regulation of exocytosis by CAPS, Ca2+, and potential novel cytosolic factor(s) suggests that the docking and fusion machinery controlling DCVs has diverged from that regulating glutamate-containing SVs.

Publication types

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

MeSH terms

  • Animals
  • Caenorhabditis elegans Proteins*
  • Calcium / physiology*
  • Calcium-Binding Proteins*
  • Cytosol / metabolism
  • Cytosol / physiology
  • Exocytosis / physiology*
  • Glutamic Acid / metabolism
  • Helminth Proteins / immunology
  • Helminth Proteins / physiology*
  • Male
  • Membrane Proteins / physiology
  • Neurotransmitter Agents / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • SNARE Proteins
  • Synaptosomes / metabolism
  • Synaptosomes / physiology*
  • Vesicular Transport Proteins*


  • Caenorhabditis elegans Proteins
  • Calcium-Binding Proteins
  • Helminth Proteins
  • Membrane Proteins
  • Neurotransmitter Agents
  • SNARE Proteins
  • UNC-31 protein, C elegans
  • Vesicular Transport Proteins
  • Glutamic Acid
  • Calcium