Effect of the Black Snake Toxin on the Gastrocnemius-sciatic Preparation

When the toxin of the black snake {Walterirmesia aegyptea) was injected subcutaneously into albino rats, one of the common symptoms which appeared was the paralysis which takes place in the limb near the site of injection and extends to other limbs just before death. Such observations led us to examine the changes produced in a stimulated gastrocnemius-sciatic preparation of Bufo to show the effect of the toxin and the site of its action. No work had been done on the action of the black snake toxin on the nervemuscle preparation. Yet much work has been published about such data for other poisonous snakes. Lauder, Brunton & Fayrer (1874) were the first to demonstrate a curare-like action of cobra venom in dogs. Epstein (1930) observed complete loss of excitability of voluntary muscles brought about by cape cobra venom and Kellaway & Holden (1932) demonstrated the direct action of venom on muscles. Sarker (1951) has reported the action of Indian cobra venom both on the muscle and neuromuscular junction, the paralysis of the latter setting in much earlier and with smaller concentrations of the venom. The aim of this work was to study the following points: (1) The effect of the toxin of the black snake on the contraction height of gastrocnemius muscle when stimulated directly and/or indirectly. (2) The site of action of the toxin. (3) The mechanism of action of the toxin.