Mode of action of Duvernoy's gland extracts from the colubrid Dryadophis bifossatus in the chick biventer cervicis nerve-muscle preparation

Extracts and secretion of the Duvernoy's gland are venomous, inducing in several cases motor paralysis in experimental animals. The extracts of the Duvernoy's gland from the aglyphous colubrid Dryadophis bifossatus are very toxic, eliciting flaccid paralysis in pigeons, rabbits and Hylae (Brazil and Vellard, 1926). In the present study, the neuromuscular action of the extracts of Duvernoy's gland from this Colubridae was investigated in the chick biventer cervicis nerve-muscle preparation. The muscle was indirectly stimulated with supramaximal pulses, and by addition of acetylcholine or carbachol to the organ bath. Direct muscle stimulation was carried out in curarized preparations. The extracts induced an irreversible neuromuscular blockade and also inhibited irreversibly the contracture of the biventer cervicis produced by either acetylcholine or carbachol. The twitches elicited by direct muscle stimulation were not depressed. These results show that the neurotoxin(s) of the extracts interact with the end-plate cholinergic receptors. Copyright (C) 1996 Elsevier Science Ltd