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

The muscle-type nicotinic acetylcholine receptor (nmAChR) is a specialized ligand-gated ion channel essential for communication between motor neurons and skeletal muscle fibers at the neuromuscular junction [StatPearls: Physiology, Nicotinic Receptors]. It is a pentameric protein complex, typically composed of two alpha-1, one beta-1, one delta, and one epsilon subunit in adult humans [UniProt: P02708]. Upon the binding of acetylcholine to its extracellular sites, the receptor undergoes a conformational change that opens a cation-selective pore, allowing the influx of sodium and calcium ions and the efflux of potassium ions [PubMed: PMC2672959]. This depolarization triggers an action potential in the muscle fiber, ultimately leading to muscle contraction. Pathologically, the nmAChR is the primary target of autoantibodies in Myasthenia Gravis, which leads to receptor degradation and impaired neuromuscular transmission [NIH: Myasthenia Gravis]. Clinically, this receptor is the target for neuromuscular blocking agents (NMBAs) used in anesthesia to facilitate endotracheal intubation and provide muscle relaxation during surgical procedures [StatPearls: Neuromuscular Blocking Chemotherapy].

Other names

Neuromuscular nicotinic acetylcholine receptorMuscle nAChRNeuromuscular junction acetylcholine receptorCHRNMuscle-type nAChR

Agonist (depolarizing) or Antagonist (non-depolarizing) binding to the alpha subunits to modulate the opening of the cation-selective pore.