Investigation of the cardiotoxic peptides of the venom of the cobraNaja oxiana

Six populations of basic polypeptides have been found in the venom of the Central Asian cobraNaja oxiana Eichwald, and four of them — V″c-1, V″c-2, V″c-5, and V″c-6 — have been obtained in the electrophoretically homogeneous state. On a perfused frog heart preparation, all the basic polypeptides proved to be cardiotoxic. However, only some of them (V′c-2, V″c-3, and V″c-4) were characterized by arrhythmic activity as well as by the negative ino- and chronotropic effects, common for all of them. An enhancement of the specific cardiotoxic effect of each of the polypeptides by pure phospholipase A-2 has been shown.