Reconstitution of a purified acetylcholine receptor.

Dialysis of the purified acetylcholine receptor from Torpedo californica electroplax with lipids from the same organ results in a vesicular membrane system in which the receptor is embedded in the bilayer and oriented so that most of the neurotoxin-binding sites appear to be on the outer surface. The reconstituted vesicles are chemically excitable by acetylcholine and carbamylcholine, as measured by 22Na+ efflux. The excitability is specifically blocked by the antagonist alpha-bungarotoxin. These results demonstrate that the purified reconstituted receptor system not only can specifically bind neurotransmitter but can also trigger ion translocation. It therefore has the properties necessary to effect postsynaptic depolarization in vivo.