[The characteristics of the cholinoreceptors on the identified TAN neuron of the giant African snail Achatina fulica]

Abstract

Acetylcholine, nicotine, a selective agonist of N-cholinoreceptors suberildicholine dibromide, as well as a selective agonist of M-cholinoreceptors 5-methylfurmethide inhibited spike discharges in a dose-dependent manner up to a complete ceasing of the firing in cholinoreceptors situated on the identified neurone TAN of African giant snail Achatina fulica. M-cholinoblocker metamizylum completely prevented the inhibitory effect of methylfurmethide. Central cholinoblocker aetherophen completely prevented the inhibitory effect of suberildicholine dibromide. Metamizylum or aetherophen used alone were only able to decrease the inhibitory effect of acetylcholine, whereas a mixture of these agents suppressed completely the acetylcholine-induced inhibition. The findings suggest that, on the TAN membrane, nicotinic and muscarinic cholinoreceptors co-exist and function in one and the same direction.