Which antihypertensive agent lowers sympathetic outflow by irreversibly blocking vesicular monoamine transporter type 2, thereby depleting stored catecholamines from adrenergic nerve terminals?
- A Reserpine ✓
- B Alpha-methyldopa
- C Guanethidine
- D Bretylium
Correct answer: A. Reserpine
Explanation
Reserpine binds VMAT2 irreversibly and destroys vesicular storage of norepinephrine and dopamine, so transmitter leaks into the cytoplasm and is degraded by MAO, depleting terminals for days to weeks. Its major limiting adverse effect is severe depression. Guanethidine blocks release via the neuronal uptake carrier rather than vesicular storage, and methyldopa acts as a false transmitter and central alpha-2 agonist.
Reference: Katzung's Basic and Clinical Pharmacology, 15th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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