Muscarinic acetylcholine receptor
Muscarinic acetylcholine receptors (mAChRs) are acetylcholine receptors that form G protein-coupled receptor complexes in the cell membranes of certain neurons and other cells. They play several roles, including acting as the main end-receptor stimulated by acetylcholine released from postganglionic fibers.
Source: Wikipedia — Muscarinic acetylcholine receptor (CC BY-SA 4.0)