Topics:
Animal Physiology, Animal Refresher
Most Potent Vasodilator in the Body
The most potent vasodilator produced in the body is:
- Heparin
- Prostacyclin (PGI₂)
- Endothelin
- Nitric oxide — Correct Answer
Explanation:
Correct Answer: Nitric oxide
Nitric oxide (NO) is the most potent vasodilator produced in the body. It is synthesized by endothelial cells from L-arginine by the enzyme eNOS (endothelial Nitric Oxide Synthase).
Mechanism of Nitric Oxide Vasodilation
NO diffuses into vascular smooth muscle cells → activates guanylate cyclase → increases cGMP → activates protein kinase G → smooth muscle relaxation → vasodilation
Key Facts About Nitric Oxide
- Also known as Endothelium-Derived Relaxing Factor (EDRF)
- Half-life is very short (seconds) — acts locally
- Nitric oxide (NO) was discovered to be EDRF — discovery earned the 1998 Nobel Prize in Physiology or Medicine
- Drugs like nitroglycerin work by releasing NO → treating angina (heart pain due to coronary spasm)
Vasodilators Summary
- Nitric oxide (NO): Most potent vasodilator
- Atrial natriuretic peptide (ANP): also reduces blood pressure
- Prostacyclin (PGI₂): inhibits platelet aggregation AND causes vasodilation
- Histamine, bradykinin, VIP, substance P, PAF, PGE₂: all vasodilators
Compare
Most potent vasoconstrictor = Endothelin; Most potent vasodilator = Nitric oxide
📚 About this Topic — Animal Physiology
This multiple choice question is from Animal Physiology, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Physiology to strengthen your preparation.
