Presynaptic calcium currents in squid giant synapse

Biophys J. 1981 Mar;33(3):289-321. doi: 10.1016/S0006-3495(81)84898-9.


A voltage clamp study has been performed in the presynaptic terminal of the squid stellate ganglion. After blockage of the voltage-dependent sodium and potassium conductances, an inward calcium current is demonstrated. Given a step-depolarization pulse, this voltage- and time-dependent conductance has an S-shaped onset. At the "break" of the voltage step, a rapid tail current is observed. From these results a kinetic model is generated which accounts for the experimental results and predicts for the time course and amplitude a possible calcium entry during presynaptic action potentials.

Publication types

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

MeSH terms

  • Action Potentials / drug effects
  • Animals
  • Calcium / pharmacology*
  • Decapodiformes
  • Electric Conductivity
  • Electric Stimulation
  • Ganglia / physiology*
  • Kinetics
  • Mathematics
  • Membrane Potentials / drug effects
  • Synapses / drug effects
  • Synapses / physiology*


  • Calcium