Skeletal muscle nicotinic acetylcholine receptor (nAChR (muscle-type), or muscle-type nAChR)

The skeletal muscle nicotinic acetylcholine receptor is a ligand-gated ion channel found at the neuromuscular junction and is the key mediator of fast synaptic transmission between motor neurons and skeletal muscle fibers. It is a heteropentameric protein complex typically composed of two α1, one β1, one δ, and one ε (adult) or γ (fetal) subunits. Upon binding two molecules of acetylcholine released from motor neurons, the receptor undergoes a conformational change that opens its ion channel pore, allowing rapid influx of sodium ions and efflux of potassium ions, initiating muscle membrane depolarization and triggering muscle contraction. It is essential for voluntary movement, and its malfunction or blockade is linked to pathologies such as myasthenia gravis, congenital myasthenic syndromes, and paralysis by neurotoxins or clinical muscle relaxants[1][3][5][8][9].

Other names

muscle-type nicotinic acetylcholine receptormuscle nAChRneuromuscular nicotinic receptornicotinic acetylcholine receptor (muscle type)muscle AChR

Agonists open the ion channel to allow cation influx (mainly Na^+, some K^+, and Ca^2+^), leading to depolarization and muscle contraction; Antagonists compete for the acetylcholine binding site (competitive block) or bind irreversibly (non-competitive, e.g., alpha-bungarotoxin), leading to muscle relaxation or paralysis[1][5][6][9].