The antagonism of acetylcholine excitatory and inhibitory responses of Helix central neurones, by some neuromuscular blocking drugs.

Intracellular recordings were made from identified central neurones of the snail Helix aspersa. The antagonism of acetylcholine excitatory and inhibitory responses by d-tubocurarine, HS818 and HS626 was investigated. d-Tubocurarine was equipotent against both the inhibitory and excitatory responses, while HS626 and HS818 were of similar potency to d-tubocurarine in antagonising acetylcholine excitation but were approximately one order of magnitude less potent in antagonising the inhibitory response.