The voltage-dependent sodium channel is co-localized with the acetylcholine receptor at the vertebrate neuromuscular junction.

Isolated motor endplates from mouse intercostal muscles can be obtained after subcellular fractionation. On these motor endplates, localization of the nicotinic receptor and of the voltage-dependent Na+ channel coincides as demonstrated by double labeling with rhodamine alpha-bungarotoxin and a specific anti-Na+ channel monoclonal antibody. High density of Na+ channel at the motor endplate is confirmed by the enrichment in TTX binding sites as compared to the crude homogenate. In contrast isolated motor endplates are almost completely devoid of Ca2+ channel antagonist binding sites.