Muscle nicotinic acetylcholine receptor (adult) (nAChR) (nAChR)

The human adult muscle nicotinic acetylcholine receptor is a pentameric ligand-gated ion channel located at the postsynaptic membrane of the neuromuscular junction. It is composed of two alpha-1, one beta-1, one delta, and one epsilon subunit, a configuration that distinguishes it from the fetal form which contains a gamma subunit (StatPearls, 2023). The receptor's primary biological role is to mediate fast excitatory transmission by opening a cation-selective pore in response to the binding of acetylcholine, which leads to muscle fiber depolarization and subsequent contraction (PubMed, PMC2679882). In clinical medicine, this receptor is a major therapeutic target for neuromuscular blocking agents used during surgery to facilitate intubation and provide muscle relaxation (NIH, 2022). It is also the primary target of autoimmune attack in Myasthenia Gravis, where antibodies against the receptor cause its internalisation and destruction, resulting in severe muscle weakness (UniProt, P02708). Furthermore, various congenital myasthenic syndromes arise from genetic mutations in the subunits of this receptor, affecting its expression or kinetic properties (PubMed, 25533363).

Other names

Adult muscle-type nicotinic acetylcholine receptorCHRNA1/CHRNB1/CHRND/CHRNE complexNeuromuscular nicotinic acetylcholine receptorAdult-type muscle nAChR

Drugs targeting this receptor primarily function through two distinct mechanisms: competitive antagonism, where non-depolarizing agents bind to the receptor to prevent acetylcholine from initiating an action potential, and depolarizing agonism, where agents like succinylcholine cause persistent activation leading to receptor desensitization and muscle relaxation.