The positive inotropic effect of digitalis due to inhibition of the Na+/K+ ATPase pump in cardiac muscle cell membrane leads to:

A. Decreased activity of Na+/Ca++ exchanger causing decreased 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 Na+ and increased influx of Ca++ through Na+/ Ca++ exchanger in the sarcolemma

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

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

Description: Digitalis selectively binds to the extracellular face of membrane- Na-k ATPase is inhibited. Inhibition of this cation pump results in progressive accumulation of Na intracellularly. Indirectly result in intracellular Calcium accumulation. REF.Essentials of medical pharmacology K D TRIPATHI 6 Edition)

Category: Pharmacology

Share:

← Previous MCQ

Next MCQ →

Get More

Subject Mock Tests

Practice with over 200,000 questions from various medical subjects and improve your knowledge.

Attempt a mock test now

Mock Exam

Take an exam with 100 random questions selected from all subjects to test your knowledge.

Coming Soon

Get More

Subject Mock Tests

Try practicing mock tests with over 200,000 questions from various medical subjects.

Attempt a mock test now

Mock Exam

Attempt an exam of 100 questions randomly chosen from all subjects.

Coming Soon