Nicotinic acetylcholine receptor

Nicotinic acetylcholine receptors, or nAChRs, are cholinergic receptors that form ligand-gated ion channels in the plasma membranes of certain neurons and on the postsynaptic side of the neuromuscular junction <!-- and other cell -->. As ionotropic receptors, nAChRs are directly linked to ion channels and do not use second messengers (as metabotropic receptors do).

Like the other type of acetylcholine receptor — the muscarinic acetylcholine receptor (mAChR) — the nAChR is triggered by the binding of the neurotransmitter acetylcholine (ACh). However, whereas muscarinic receptors are also activated by muscarine, nicotinic receptors can be opened by nicotine - hence the name "nicotinic".

Nicotinic acetylcholine receptors are present in many tissues in the body and are the best-studied of the ionotropic receptors. The neuronal receptors are found in the central nervous system and the peripheral nervous system. The neuromuscular receptors are found in the neuromuscular junctions of somatic muscle; stimulation of these receptors causes muscular contraction.

Structure

Nicotinic receptors, with a molecular mass of 290 kDa, are made up of five subunits, arranged symmetrically around a central pore.<ref...
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