Amphetamine produces its sympathomimetic effects primarily by:
- A Inhibiting norepinephrine reuptake transporter (NET) and promoting reverse transport of catecholamines ✓
- B Directly stimulating alpha and beta adrenergic receptors
- C Inhibiting monoamine oxidase in sympathetic nerve terminals
- D Blocking alpha-2 autoreceptors to increase norepinephrine release
Correct answer: A. Inhibiting norepinephrine reuptake transporter (NET) and promoting reverse transport of catecholamines
Explanation
Amphetamine is an indirect sympathomimetic that enters the nerve terminal via the norepinephrine transporter (NET), displaces norepinephrine from vesicles into the cytoplasm, and causes reverse transport through NET to expel norepinephrine into the synapse. It also inhibits MAO within the terminal and has weak direct receptor activity, but the predominant mechanism is carrier-mediated efflux. Tachyphylaxis develops because stored norepinephrine is depleted.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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