Nicotinic acetylcholine receptor (muscle-type) at the neuromuscular junction (nAChR (muscle-type))

The nicotinic acetylcholine receptor (muscle-type) is a pentameric ligand-gated ion channel highly concentrated at the postsynaptic membrane of skeletal muscle fibers at the neuromuscular junction (NMJ). Activation occurs as acetylcholine released from presynaptic motor neurons binds to the extracellular domain of the receptor, triggering the opening of its central ion-conducting pore and allowing sodium influx, which depolarizes the muscle membrane and leads to muscle contraction. There are two isoforms: a fetal (α1β1γδ) and adult (α1β1εδ) form, differing by a single subunit during development. The nAChR at the NMJ is implicated in multiple disease states (including myasthenia gravis and ALS), is a major therapeutic target for muscle relaxants and cholinesterase inhibitors, and is a classic example of a synaptic receptor-ion channel complex central to fast synaptic neurotransmission in vertebrate skeletal muscle.

Other names

Nicotinic acetylcholine receptor (muscle-type)Muscle-type nicotinic acetylcholine receptornAChR (muscle-type)Acetylcholine receptor (at neuromuscular junction)Motor endplate nAChR

Neuromuscular blockers: Act as competitive antagonists of the nAChR, inhibiting acetylcholine binding and resulting in muscle relaxation or paralysis. Acetylcholinesterase inhibitors: Indirectly potentiate nAChR signaling by preventing acetylcholine breakdown, increasing its availability at the receptor. α-neurotoxins/conotoxins: Bind irreversibly or selectively to nAChRs, blocking ion flux and preventing muscle contraction.