Nicotinic Acetylcholine Receptor (Neuromuscular) (nAChR)

Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels that respond to the neurotransmitter acetylcholine and the exogenous agonist nicotine. They are found in both the central and peripheral nervous systems, as well as in muscle tissue, where they play a critical role at neuromuscular junctions by mediating fast synaptic transmission and triggering muscle contraction. nAChRs are pentameric complexes composed of five subunits arranged around a central pore. In mammals, 17 different subunits have been identified. The muscle-type nAChR at the neuromuscular junction is typically made up of two α1 subunits plus one each of β1, δ, and either γ (fetal form) or ε (adult form). At neuromuscular junctions, activation by acetylcholine leads to opening of a non-selective cation channel allowing Na⁺ influx and K⁺ efflux; this depolarizes the postsynaptic membrane leading to muscle contraction. Dysfunction or autoimmune targeting leads to diseases such as myasthenia gravis. nAChRs are major drug targets for muscle relaxants during surgery and treatment strategies for neurological diseases involving cholinergic dysfunction. Mutations affecting specific nAChR subunit genes can cause inherited disorders like autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE).

Other names

Nicotinic acetylcholine receptorAChRnACh receptor

Activation by acetylcholine leads to opening of a non-selective cation channel allowing Na⁺ influx and K⁺ efflux; this depolarizes the postsynaptic membrane leading to muscle contraction