[Effect of polarizing mixture on the toxicity and cardiotonic effect of strophanthin]

Experiments on doves and frogs with a biological valorization of Strophantin reveale a decreasing biological activity of the glycoside under the effect of a polarizing mixture by 54.2% and 28.5%, respectively. The LD50 test in mice also demonstrated a 50% decrease of Strophantin toxicity. Electrocardiographic studies conducted in mice and rats (with a fractionated administration of the glycoside) showed that the polarizing mixture decelerates the development of a negative chronotropic action of Strophantin, and in the presence of toxic doses of the glycoside it weakens its effect upon the excitability and conductivity of the myocardium. In experiments with rabbits and recording of their left ventricular pressure a decreasing cardiotonic effect of Strophantin under the effect of the polarizing mixture was also established, both in the intact animals, and in those with an experimentally induced myocardial infarction. The weakening of the cardiotonic effect and of the toxicity of Strophantin is interpreted in terms of the anatagonistic effects of the glycoside and insulin on the system "catecholamines -- cyclic 3,5 -- AMP", as well as in terms of their effect on the bioenergetics of the myocardium and the dynamics of the content of intracellular potassium.