More About nAChR
Nicotinergic acetylcholine receptors are made up of 5 subunits, symmetrically arranged around a central pore (ion channel). It is considered the best-characterized LGIC and a prototypical structure for the class of 4TM receptors. nAChRs are found mainly in postsynaptic membranes of central nervous system synapses and of the neuromuscular endplate. The physiological signal to which nAChR responds is the neurotransmitter acetylcholine, but it is also activated by nicotine. The assembly of combinations of subunits (17 distinct subunits have been identified) results in a large number of different receptors with a high variety of functional diversity as a result[1].
[1] Ligand-Gated Ion Channels. F. Hucho, C. Weise. Angew.Chem.Int.Ed. 2001, 40, 3100-3116.