What are the action of cardiac glycosides

Ca2+ is extruded via the Na +-Ca 2+ exchanger Driven by Na+ moving down its concentration gradient Cardiac glycosides block the Na+/K+ ATPase Hence leads to rise in Na+ conc intracellularly Rise in intracellular Na + leads to decrease in activity of Na + -Ca 2+ exchanger and this causes increase in [Ca2] Hence more is stored in the sarcoplasmic reticulum Increased force of contraction → Positive inotropic effect Cardiac glycosides also increase vagus nerve activity → parasympathetic NS so slows down HR and AV conduction