Muscle-type nicotinic acetylcholine receptor (mnAChR) (mnAChR)

The muscle-type nicotinic acetylcholine receptor (mnAChR) is a pentameric ligand-gated ion channel located at the postsynaptic membrane of the neuromuscular junction (NMJ) [StatPearls: NBK537184]. It is composed of five subunits: two alpha-1, one beta-1, one delta, and either one epsilon (adult form) or one gamma (fetal form) subunit [UniProt: P02708]. The receptor functions by binding two molecules of acetylcholine, which triggers a conformational change that opens a cation-selective pore, allowing sodium and calcium influx and potassium efflux [PubMed: 16159063]. This depolarization, known as the end-plate potential, triggers an action potential that leads to skeletal muscle contraction. The mnAChR is a major pharmacological target for neuromuscular blocking agents (NMBAs) used in anesthesia to provide muscle relaxation [StatPearls: NBK535381]. Additionally, it is the primary autoantigen in Myasthenia Gravis, where autoantibodies target the receptor, leading to its degradation and impaired neuromuscular transmission [NIH: Myasthenia Gravis].

Other names

Muscle nicotinic acetylcholine receptorNeuromuscular nicotinic acetylcholine receptornAChR (muscle-type)Adult muscle nAChRFetal muscle nAChR

Competitive antagonism of the acetylcholine binding site (non-depolarizing blockade) or persistent activation leading to receptor desensitization and sodium channel inactivation (depolarizing blockade) [StatPearls: NBK535381].