Effect of nucleosides, strophanthin, and combinations of these factors on the development of fatigue in the myocardium

Abstract

A study was made of the effect produced by nucleosides (uridine, inosine and bases included into their composition—uracil and hypoxanthine) on the development of fatigue in the myocardium. The latter process was induced in acute experimental conditions by repeated overloading of the left cardiac ventricle by complete occlusion of the ascending aorta for 30 sec. The interval between the occlusions was 5 min. The maximal systolic pressure observed during aortic compression decreased with each subsequent compression, notwithstanding the unchanged or rising endodiastolic pressure. The dynamics of reduction of the maximal level of cardiac contractile function characterizes the process of fatigue. Administration of uridine, inosine and hypoxanthine following the fifth compression inhibits the further development of the fatigue process; the same effect is produced by strophanthin. Administration of a combination of uridine, uracil inosine, hypoxanthine and strophanthin eliminated the fatigue phenomena and increased the maximal level of the cardiac contractile function to a greater degree and for a longer time than separate administration of the same agents.