Cardioactive steroids, like digoxin, exert a positive ionotropic effect on heart muscle cells. Because of this activity they can be used clinically to increase contraction of a failing heart. Which of the following proteins is important in the mechanism of action of digoxin on the cardiac muscle cell?

Question

Quizplus · Accepted Answer

Digoxin inhibits the Na⁺/K⁺ ATPase, leading to increased intracellular Na⁺, which reduces the activity of the Na⁺/Ca²⁺ exchanger (NCX), resulting in increased intracellular Ca²⁺ and enhanced cardiac contractility.

Cardioactive Steroids, Like Digoxin, Exert a Positive Ionotropic Effect on Heart