muscarinic acetylcholine receptormuscarinic cholinergic receptorsmuscarinic and nicotinic receptorsanti muscarinicm3 muscarinic receptorm4 muscarinic receptormuscarinic acetylcholinemuscarinic acetylcholine receptor m1cholinergic muscarinicmuscarinic acetylcholine receptor m3muscarinic acetylcholine receptor m4m2 muscarinic receptor