Muscarinic acetylcholine receptor

Muscarinic acetylcholine receptors (mAChRs) are acetylcholine receptors that form G protein-coupled receptor complexes in the cell membranes of certain neurons^[1] and other cells. They play several roles, including acting as the main end-receptor stimulated by acetylcholine released from postganglionic fibers. They are mainly found in the parasympathetic nervous system, but also have a role in the sympathetic nervous system in the control of sweat glands.^[2]

Muscarinic receptors are so named because they are more sensitive to muscarine than to nicotine.^[3] Their counterparts are nicotinic acetylcholine receptors (nAChRs), receptor ion channels that are also important in the autonomic nervous system. Many drugs and other substances (for example pilocarpine and scopolamine) manipulate these two distinct receptors by acting as selective agonists or antagonists.^[4]