Effects of intra-axonal injection of Ca2+ buffers on evoked release and on facilitation in the crayfish neuromuscular junction

Neurosci Lett. 1991 Apr 29;125(2):215-8. doi: 10.1016/0304-3940(91)90032-o.

Abstract

Ca2+ buffers were injected into the excitatory axon of the crayfish opener muscle. The magnitude and time course of evoked release and of facilitation were measured. EGTA (on-rate about 10(6) M-1S-1) had no effect on evoked release but reduced facilitation. BAPTA and nitr-5, buffers with similar Kd's but faster on-rates, reduced both evoked release and facilitation. However, these buffers had no effect on the time course of evoked release. These results show that fast Ca2+ buffers reduce the Ca2+ transient associated with evoked release and also the level of residual Ca2+ involved in facilitation. However, Ca2+ buffering is not the mechanism which controls the time course of release.

Publication types

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

MeSH terms

  • Animals
  • Astacoidea
  • Buffers
  • Calcium / pharmacology*
  • Egtazic Acid / pharmacology
  • Evoked Potentials
  • In Vitro Techniques
  • Neuromuscular Junction / drug effects
  • Neuromuscular Junction / physiology*
  • Synapses / drug effects
  • Synapses / physiology
  • Time Factors

Substances

  • Buffers
  • Egtazic Acid
  • 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid
  • Calcium