Digitalis glycosideと核酸關連物質との伍用作用に就て

Abstract

Functional and cytochemical experiments were carried out on the cardiac movement and dephosphorylation in the hearts of frogs, toads and mice with a combination of digitalis glycoside such as digitoxine or g-strophanthine, ATP and DNase following Shionoya's 3rd method and Allen's method, from which the following results were obtained : DNase and ATP, generally, cause a stimulant action on the isolated frog's heart. Moreover, ATP has a potentiation of its action to DNase. On the other hand, DNase shows a synergistic action to the therapeutic phase of digitoxine or g-strophanthine. Furthermore, DNase and ATP have a specific effect on digitalis glycoside. (1) DNase shows a powerful antagonistic action to the toxic phase of digitoxine. (2) ATP shows the same action which, however, is somewhat weaker. (3) A combination of digitalis glycoside and DNase shows a powerful accelerated dephosphorylation in the heart tissues of the toads and mice. (4) Individual digitalis glycoside or a combination of digitalis glycoside and ATP shows the same dephosphorylation which, however, is somewhat weaker. The above results suggest that there exist synergistic effects on the cardiotonic actions among the therapeutic phase of digitalis glycoside, ATP and DNase ; they especially suggest that the combined effects on the cardiotonic actions among them increase in proportion to acceleration of dephosphorylation in the heart. They can be considered to provide further support for the previous ly proposed Nakatsuka's hypothesis that digitalis glycoside accelerates, primarily, nucleic acid metabolism and causes, secondarily, an increase in the rate of breakdown of energy-rich phosphate in the myocardium ; namely, that digitalis glycoside accelerates -ATP metabolism in the heart muscle through direct interaction with nucleic acid metabolism.