NDMB Alpha Subunit Blockade — FRCA Primary MCQ
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Correct answer: B — Competitive antagonism at nicotinic acetylcholine receptors prevents channel opening
The best answer is “Competitive antagonism at nicotinic acetylcholine receptors prevents channel opening”. Rocuronium is a non-depolarising neuromuscular blocker: it competitively antagonises acetylcholine at the postsynaptic nicotinic receptor and prevents the channel opening required for end-plate depolarisation. This differs from suxamethonium’s initial depolarising action and from presynaptic mechanisms that reduce acetylcholine release.
Reference: Royal College of Anaesthetists, Primary FRCA Syllabus 2021: https://www.rcoa.ac.uk/sites/default/files/documents/2026-01/Primary-FRCA-Syllabus.pdf