[Effects of pH on the processes of excitation-contraction coupling of bullfrog atrium (author's transl)]

Abstract

It has long been demonstrated that in cardiac muscle alterations in the extracellular pH exhibit a remarkable inotropic effect, whereas the precise mechanism is not fully clarified yet in spite of many associated thories. In recent years, however, abundant informations about the processes of excitation-contraction coupling (E-C coupling) of cardiac muscle have been obtained. Accordingly, the mechanisms of inotropic actions of pH on cardiac muscles must also be re-examined on the basis of these lately developed theories of E-C coupling. In the present experiment, therefore, we attempted to elucidate the fundamental mechanism of actions of pH upon several processes of E-C coupling using the bullfrog atrium whose processes of E-C coupling have been fairly well known...