Succinylcholine produces flaccid skeletal muscle paralysis primarily by which mechanism?

• A Competitive antagonism of acetylcholine at the postsynaptic nicotinic receptor
• B Blockade of voltage-gated calcium channels at the nerve terminal
• C Inhibition of acetylcholine release from the presynaptic nerve terminal
• D Persistent depolarisation of the motor end plate ✓

Explanation

Succinylcholine is a nicotinic receptor agonist that binds the end plate receptor and keeps it depolarised, producing initial fasciculations followed by flaccid paralysis. This depolarising block cannot be reversed by anticholinesterases, unlike the competitive antagonism seen with non-depolarising agents such as vecuronium. Presynaptic mechanisms are irrelevant to its primary action.

Reference: Katzung Basic and Clinical Pharmacology, 15th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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