Which of the following is not true about the mechanism of action of digitalis?
Ans. is 'a' i.e., It binds to the intracellular face of Na+ K+ ATPase enzyme Digitalis mechanism of action* Digitalis increases the force of contraction by a direct action independent of the innervation.* It binds to the extracellular face of the Na+ K+ ATPase and inhibits the enzyme causing rise in the intracellular levels of Na+.* The raised Na+ in turn inhibits the Na+ Ca2+ exchanger and causes rise in intracellular Ca2+.* This raised intracellular Ca2+ is responsible for the positive ionotropic effect.* Thus, digitalis increases the cardiac contractability and force of contraction.
It binds to the intracellular face of Na+ K+ ATPase enzyme
There is rise in intracellular Na+
It has positive ionotropic action
Digitalis action is independent of cardiac innervation
C.V.S