Inactivation of presynaptic calcium current contributes to synaptic depression at a fast central synapse

Neuron. 1998 Apr;20(4):797-807. doi: 10.1016/s0896-6273(00)81017-x.


Voltage-gated calcium channels are well characterized at neuronal somata but less thoroughly understood at the presynaptic terminal where they trigger transmitter release. In order to elucidate how the intrinsic properties of presynaptic calcium channels influence synaptic function, we have made direct recordings of the presynaptic calcium current (I(pCa)) in a brainstem giant synapse called the calyx of Held. The current was pharmacologically classified as P-type and exhibited marked inactivation. The inactivation was largely dependent upon the inward calcium current magnitude rather than the membrane potential, displayed little selectivity between divalent charge carriers (Ca2+, Ba2+ and Sr+), and exhibited slow recovery. Simultaneous pre- and postsynaptic whole-cell recording revealed that I(pCa) inactivation predominantly contributes to posttetanic depression of EPSCs. Thus, because of its slow recovery, I(pCa) inactivation underlies this short-term synaptic plasticity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Barium / metabolism
  • Brain Stem / physiology*
  • Calcium / metabolism*
  • Calcium Channel Blockers / pharmacology*
  • Calcium Channels / classification
  • Calcium Channels / physiology*
  • Evoked Potentials / drug effects
  • Evoked Potentials / physiology*
  • In Vitro Techniques
  • Membrane Potentials / drug effects
  • Membrane Potentials / physiology
  • Nimodipine / pharmacology
  • Peptides / pharmacology
  • Rats
  • Rats, Inbred Strains
  • Rats, Wistar
  • Reaction Time
  • Spider Venoms / pharmacology
  • Strontium / metabolism
  • Synapses / drug effects
  • Synapses / physiology*
  • omega-Agatoxin IVA
  • omega-Conotoxin GVIA


  • Calcium Channel Blockers
  • Calcium Channels
  • Peptides
  • Spider Venoms
  • omega-Agatoxin IVA
  • Barium
  • Nimodipine
  • omega-Conotoxin GVIA
  • Calcium
  • Strontium