Angiotensin II acts on two receptor subtypes with largely opposing vascular effects. Which of the following responses is mediated primarily through the AT2 receptor?

• A Vasodilation with antiproliferative effects on vascular smooth muscle ✓
• B Vasoconstriction of resistance vessels
• C Stimulation of aldosterone secretion from the zona glomerulosa
• D Facilitation of norepinephrine release from sympathetic nerve endings

Explanation

The AT2 receptor, abundant in fetal tissue and re-expressed after vascular injury, promotes vasodilation partly through bradykinin and nitric oxide pathways and inhibits smooth muscle growth. All classical pressor and trophic actions listed in the other options are AT1 receptor mediated, which is why AT1 blockers lower pressure while AT2 stimulation opposes remodeling. This contrast between the two subtypes is the discriminating fact being tested.

Reference: Katzung's Basic and Clinical Pharmacology, 16th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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