Distribution of Na+ channels and ankyrin in neuromuscular junctions is complementary to that of acetylcholine receptors and the 43 kd protein

Neuron. 1989 Aug;3(2):163-75. doi: 10.1016/0896-6273(89)90029-9.

Abstract

We have used immunogold electron microscopy to study the organization of the acetylcholine receptor, 43 kd protein, voltage-sensitive Na+ channel, and ankyrin in the postsynaptic membrane of the rat neuromuscular junction. The acetylcholine receptor and the 43 kd protein are concentrated at the crests of the postsynaptic folds, coextensive with the subsynaptic density. In contrast, Na+ channels and ankyrin are concentrated in the membranes of the troughs and in perijunctional membranes, both characterized by discontinuous submembrane electron-dense plaques. This configuration of interspersed postsynaptic membrane domains enriched in either Na+ channels or acetylcholine receptors may facilitate the initiation of the muscle action potential. Furthermore, the results support the involvement of ankyrin in immobilizing Na+ channels in specific membrane domains, analogous to the proposed involvement of the 43 kd protein in acetylcholine receptor immobilization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Ankyrins
  • Blood Proteins / analysis
  • Blood Proteins / metabolism*
  • Blood Proteins / physiology
  • Diaphragm / cytology
  • Diaphragm / metabolism
  • Immunohistochemistry
  • Membrane Proteins / analysis
  • Membrane Proteins / metabolism*
  • Membrane Proteins / physiology
  • Microscopy, Electron
  • Neuromuscular Junction / analysis
  • Neuromuscular Junction / metabolism*
  • Neuromuscular Junction / ultrastructure
  • Rats
  • Receptors, Cholinergic / analysis
  • Receptors, Cholinergic / metabolism*
  • Sodium Channels / metabolism
  • Sodium Channels / physiology
  • Sodium Channels / ultrastructure*
  • Synaptic Membranes / analysis
  • Synaptic Membranes / metabolism
  • Synaptic Membranes / ultrastructure

Substances

  • Ankyrins
  • Blood Proteins
  • Membrane Proteins
  • Receptors, Cholinergic
  • Sodium Channels