Abstract
Effects of various cholinergic agents on the motility of Angiostrongylus cantonensis were studied to define the neuropharmacological properties of this worm. Stimulation of the motility and/or contraction were shown by eserine, ACh, carbachol, nicotine, DMPP, pyrantel, and Ba2+, but not by pilocarpine and McN-A-343. Contraction was similarly observed by these agents in the preparations paralyzed with praziquantel. Paralysis was caused remarkably by d-tubocurarine and slightly by succinylcholine, while the contraction induced by eserine and DMPP was little influenced by these drugs. Both the motility and the eserine-induced contraction were little influenced by hexamethonium, but stimulated remarkably by atropine. Though hemicholinium-3, morphine, and picrate showed little effect, guanidine stimulated remarkably the motility and also the eserine-induced contraction. The stimulatory action of guanidine was antagonized by strychnine. Strychnine paralyzed the motility, and the eserine-induced contraction was antagonized by the pre and post-treatment with strychnine. From these results, it is suggested that the excitatory cholinergic mechanism in A. cantonensis is nicotinic, and it is basically similar to that reported in Ascaris suum.
