[The prevention of the development of myocardial contracture in the "calcium paradox" by action on Na-Ca metabolism].

The effect of artificial high sodium gradient on the rate of the myocardium contracture development during "calcium paradox" was studied in the experiments on the isolated heart of Langendorf-perfused rats. It is stated that artificial creation of a high sodium gradient decreases the rate of the myocardium contracture development. Exogenous nucleotides, activators of Na, K-ATPase, and their precursors intensified the protective action of the hypersodium medium. Phosphocreatine (100 mmol/l) had no protective effect during the "calcium paradox". However, under conditions of the high sodium gradient phosphocreatine efficiently prevented development of the contracture during the "calcium paradox". It is important to note that under analogous conditions creation of high osmosity of the solution adding 12 mmol/l of saccharose does not protect the heart from development of the myocardium contracture.