Strategic location of calcium channels at transmitter release sites of frog neuromuscular synapses

Neuron. 1990 Dec;5(6):773-9. doi: 10.1016/0896-6273(90)90336-e.


The localization of Ca2+ channels relative to the position of transmitter release sites was investigated at the frog neuromuscular junction (NMJ). Ca2+ channels were labeled with fluorescently tagged omega-conotoxin GVIA, an irreversible Ca2+ channel ligand, and observed with a confocal laser scanning microscope. The Ca2+ channel labeling almost perfectly matched that of acetylcholine receptors which were labeled with fluorescent alpha-bung-arotoxin. This indicates that groups of Ca2+ channels are localized exclusively at the active zones of the frog NMJ. Cross sections of NMJs showed that Ca2+ channels are clustered on the presynaptic membrane adjacent to the postsynaptic membrane.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biotin
  • Bungarotoxins / metabolism
  • Calcium Channels / metabolism*
  • Fluorescent Dyes
  • Mollusk Venoms / metabolism
  • Neuromuscular Junction / metabolism*
  • Neuromuscular Junction / physiology
  • Neurotransmitter Agents / metabolism*
  • Rana pipiens
  • Receptors, Cholinergic / analysis
  • Receptors, Cholinergic / metabolism
  • Synapses / metabolism*
  • Synapses / physiology
  • omega-Conotoxin GVIA


  • Bungarotoxins
  • Calcium Channels
  • Fluorescent Dyes
  • Mollusk Venoms
  • Neurotransmitter Agents
  • Receptors, Cholinergic
  • Biotin
  • omega-Conotoxin GVIA