skip to main content

NDMB Alpha Subunit Blockade — FRCA Primary MCQ

Instant feedback + full explanation. One question, done properly.

ModeratePharmacology - NeuromuscularNDMB Alpha Subunit BlockadeFRCA Primary

Regarding non-depolarising neuromuscular block at the motor end plate which mechanism is correct?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: B — Competitive blockade of acetylcholine at the alpha subunits of the nicotinic receptor preventing ion channel opening

Non-depolarising agents competitively bind to one or both alpha subunits of the nicotinic AChR at the motor end plate preventing ACh from binding and opening the ion channel. They do not depolarise the membrane. Block can be overcome by increasing ACh concentration (anticholinesterases) or by chelation (sugammadex for aminosteroidal agents).

Reference: Peck Hill Williams 2014 Pharmacology for Anaesthesia and Intensive Care