The positive inotropic effect of digitalyzers is due to invitation of Na+/K+ ATPase pump in cardiac muscle cell membrane leading to

A. Decrease the activity of Na+/Ca+ exchanger causing decrease the influx of sodium and decreased efflux of Ca++ in the sarcolemma

B. Decreased efflux of Na+ leading to less negative resting membrane potential and opening of voltage gated Ca+ + channels on the T tubules

C. Increased intracellular Na+ causing increased efflux of any place and increase the influx of Ca + + through Na+/ Ca + + exchanges in sarcolemma

D. Increased intracellular Na+ decreasing the activity of Ca + + pump in the sarcoplasmic reticulum

Correct Answer: Decrease the activity of Na+/Ca+ exchanger causing decrease the influx of sodium and decreased efflux of Ca++ in the sarcolemma

Description: Ref-Goodman and Gillman 12/e p802,803 The positive inotropic effect of digitalis is due to inhibition of Na+/K+ ATPase pump in cardiac muscle cell membrane leading to decreased activity of Na+/Ca++ exchanger causing decrease the influx of sodium and decreased efflux of CA++ in the sarcolemma

Category: Pharmacology

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