Postfusional control of quantal current shape

Neuron. 2004 May 27;42(4):607-18. doi: 10.1016/s0896-6273(04)00269-7.


Whether glutamate is released rapidly, in an all-or-none manner, or more slowly, in a regulated manner, is a matter of debate. We analyzed the time course of excitatory postsynaptic currents (EPSCs) at glutamatergic neuromuscular junctions of Drosophila and found that the decay phase of EPSCs was protracted to a variable extent. The protraction was more pronounced in evoked and spontaneous quantal EPSCs than in action potential-evoked multiquantal EPSCs; reduced in quantal EPSCs from endophilin null mutants, which maintain release via kiss-and-run; and dependent on synaptotagmin isoform, calcium, and protein phosphorylation. Our data indicate that glutamate is released from individual synaptic vesicles for milliseconds through a fusion pore. Quantal glutamate discharge time course depends on presynaptic calcium inflow and the molecular composition of the release machinery.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials / physiology
  • Adaptor Proteins, Signal Transducing*
  • Animals
  • Calcium Signaling / genetics
  • Calcium-Binding Proteins*
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism
  • Drosophila melanogaster / cytology
  • Drosophila melanogaster / metabolism*
  • Excitatory Postsynaptic Potentials / physiology*
  • Glutamic Acid / metabolism*
  • Larva
  • Membrane Fusion / physiology*
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / metabolism
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Neuromuscular Junction / metabolism*
  • Neuromuscular Junction / ultrastructure
  • Phosphorylation
  • Synaptic Membranes / metabolism
  • Synaptic Membranes / ultrastructure
  • Synaptic Transmission / physiology*
  • Synaptic Vesicles / metabolism*
  • Synaptic Vesicles / ultrastructure
  • Synaptotagmins
  • Time Factors


  • Adaptor Proteins, Signal Transducing
  • Calcium-Binding Proteins
  • Carrier Proteins
  • Membrane Glycoproteins
  • Nerve Tissue Proteins
  • Synaptotagmins
  • Glutamic Acid