nicotinic acetylcholine receptor

(= nAChR)

Integral membrane protein of the postsynaptic membrane to which acetylcholine binds. The receptor contains an integral ion channel; as a result of binding of acetylcholine, ion channels in the subsynaptic membrane are opened. At the neuromuscular junction, the nicotinic acetylcholine receptor initiates muscle contraction. Currently the best characterized ion channel protein: made of a hetero-pentamer of related subunits, although a homo-pentamer is functional in insects. Structural studies show that the acetylcholine binding site and the ionic channel are part of the same macromolecular unit. The nAChR mediates rapid transduction events (1ms) whereas receptors activating G-protein-coupled receptors operate on slower time scales (millisecond to second range).