Voltage-dependent P/Q-type calcium channels at the frog neuromuscular junction

Physiol Res. 2011;60(5):815-23. doi: 10.33549/physiolres.932219. Epub 2011 Aug 1.

Abstract

It is well known that antagonists of N-type voltage-gated calcium channels inhibit the evoked quantal release of acetylcholine in amphibian neuromuscular synapses. This, however, does not exclude the functional expression of other types of voltage-gated calcium channels in these nerve terminals. Using immunocytochemistry, we detected the expression of the alpha1A subunit of P/Q-type calcium channels (that is otherwise typical of mammalian motor nerve endings) in the frog neuromuscular junction. In addition, we demonstrated that the P/Q-type channel blocker omega-agatoxin IVA (20 nM) reduced the action potential-induced calcium transient and significantly decreased both spontaneous and evoked mediator release. Our data indicates the functional expression of P/Q-type calcium channels in the frog motor nerve ending which participate in acetylcholine release.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / metabolism*
  • Calcium Signaling / physiology*
  • Ion Channel Gating / physiology*
  • Membrane Potentials / physiology*
  • Neuromuscular Junction / physiology*
  • Rana ridibunda
  • Synaptic Transmission / physiology*

Substances

  • Calcium