First Pharmacological Study of the Venom of a Rare African Snake, Naja multifasciata duttoni

Background: The burrowing cobra, Naja multifasciata duttoni is a rare snake that has hardly been studied because it is seldom found. Its venom has never been studied scientifically. Two specimens were impounded by UK Customs and transferred to the Liverpool School of Tropical Medicine, allowing the opportunity to collect and study the pharmacological effects of the venom of this species. Methods: Venom was milked from both snakes, pooled and dried. Aliquots were reconstituted immediately before experiments. Effects were determined on the isolated nerve muscle preparation, the chick biventer cervicis, using indirect nerve stimulation and contracture responses to acetylcholine, carbachol and KCl. Results: The venom produced a concentration-dependent reduction in the twitch responses to nerve stimulation. Complete block was reached within 20 min with 30 ug/ml, while 3 ug/ml took about 90 min to cause complete block. After responses to indirect stimulation were abolished by venom, responses to the agonists were tested: there were no responses to acetylcholine or to carbachol, while there were responses to depolarization induced by KCl. Responses to KCl were reduced after exposure to venom at 30 ug/ml and this concentration alos caused a slow contracture of the muscle preparations. Conclusions: Venom of the burrowing cobra, Naja multifasciata duttoni has similar pharmacological effects on nerve-muscle preparations as classical cobra venoms. The effects are consistent with the presence in the venom of postsynaptic neurotoxins and cardiotoxins (or 'cytotoxins')