심근 미토콘드리아의 소듐에 의한 칼슘유리가 액토마이오신 ATPase 활성도에 미치는 영향

Abstract

The calcium sensitive ATPase activity of actomy· osin extracted from dog heart was measured in a reaction condition, under which the release of calcium from cardiac mitochondria could be induced by sodium. In spite of sodium insensitivity, the ATPase activity of actomyosin, when incubated with mitoch· ondria, increased with the addition of 2~10mM sodium. Such an increase in the activity of actomyosin ATPasc was interpreted as the result of calcium release from the mitochondria by sodium. And it was also considered from the result that the sodium indo uced calcium release from mitochondria might be related with the positive inotropic effect of digitalis cardiac glycoside, which could produce the elevation of intracellular sodium secondary to the inhibition of the mcml rane sodium-pump.