Sheeza Basharatover 1 year ago

Digoxin

Digoxin binds to extracellular face of Na+/K+ ATPase on myocardial fibres. Inhibition of enzyme: progressive accumulation of more Na+ intracellularly. For 3Na+/Ca2+ antiporter: transmembrane gradient for Na+ is reduced. More calcium is retained intracellularly; more loading into intracellular stores. Subsequent contraction cycle will have higher cytosolic calcium resulting in more efficient contraction without increasing oxygen load.