The nicotinic acetylcholine receptor (nAChR) is a ligand gated ion channel that mediates neurotransmission at the neuromuscular junction, autonomic ganglia and at some sites in the central nervous system. Distinct nAChR subtypes exist that can be stimulated by the neurotransmitter acetylcholine, the natural product nicotine, or by synthetic compounds. After binding acetylcholine, Nicotinic Acetylcholine Receptor alpha 3 responds by an extensive change in conformation that affects all subunits and leads to opening of an ion conducting channel across the plasma membrane.