STUDIES ON THE POTASSIUM CONTENT OF THE HEART MUSCLE RECEIVING κ-STROPHANTHIN AND THE INFLUENCE OF POTASSIUM ON THE RESPIRATION OF HEART MUSCLE

Abstract

We have several reports on the effect of cardiac glycosides on the potassium content of heart muscle. In dogs, Calhoun and Harrison (1) observed a marked decrease in muscle potassium after toxic and fatal doses of digitalis and no significant change after therapeutic doses. Cattel and Goodell (2), who used the excised frog sartorius, and Wood and Moe (3), who studied isolated dog heart preparations, confirmed the observation that large doses of the drugs caused loss of potassium. However, Wedd (4) reported that the therapeutic action of digitalis was not the result of a lowering of the potassium content, and that when potassium loss did occur it represented a toxic effect of the drug afterwards. Hagen (5), who used the isolated rabbit hearts, and Boyer and Poindexter (6), who studied cat hearts, found that calculated therapeutic doses of digitalis caused a uniform and significant increase, whereas toxic doses produced a marked decrease in potassium. Recently, Holland and his collaborators (7), who used the isolated guinea pig hearts, and Hajdu (8), who studied isolated frog hearts, reported therapeutic doses of digitalis caused a decrease in potassium.
On the other hand, the effect of digitalis on the respiratory activity of heart muscle in vitro has attracted considerable attention. Lévy and her collaborators (9), Wollenberger (10), and Finkelstein and Bodansky (11) found that mammalian heart slices showed an increased oxygen utilization in the presence of calculated therapeutic concentrations of cardiac glycosides. However, an experiment (10) with homogenized tissue showed no effect of the glycosides on the oxygen uptake. In this connection, the possibility arises that intact cells are necessary for the demonstration of the accelerating effect of the glycosides.
Kleinzeller (12), Pressman and Lardy (13), Harman and Feigelson (14), and Korff and his collaborators (15) reported that potassium in a certain concentration produced a beneficial effect on the respiratory activity of the hamogenate or mitochondria of mammalian tissue. Then, the enhancing effect of digitalis on the respiration of heart muscle slice may have some relation with the changing effect of the drug on the potassium content of the tissue.
In the present study, effects of κ-strophanthin on the potassium content of heart muscle, and those of potassium on the respiration of homogenate and intracellular components were observed, and a relation between them was calculated.In addition, some fundamental experiments were made on the preparation and respiration of intracellular components of heart muscle, as there were not a sufficient number of studies on such subjects.