Which of the following agents blocks the reuptake of choline into the cholinergic nerve terminal, thereby depleting neuronal acetylcholine stores?
- A Vesamicol
- B Botulinum toxin
- C Hemicholinium ✓
- D Trimethaphan
Correct answer: C. Hemicholinium
Explanation
Hemicholinium blocks the high-affinity sodium-linked choline transporter on the presynaptic cholinergic nerve terminal, preventing choline reuptake and gradually depleting acetylcholine stores. Vesamicol acts one step later, blocking transport of newly synthesized acetylcholine into synaptic vesicles, which makes it the most tempting distractor. Botulinum toxin acts on SNARE proteins to prevent vesicular fusion, and trimethaphan is a nicotinic ganglionic blocker acting postsynaptically.
Reference: Katzung's Basic and Clinical Pharmacology, 15th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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