Source:http://linkedlifedata.com/resource/umls/id/C0034826
MSH: One of the two major classes of cholinergic receptors. Muscarinic receptors were originally defined by their preference for MUSCARINE over NICOTINE. There are several subtypes (usually M1, M2, M3....) that are characterized by their cellular actions, pharmacology, and molecular biology.,CSP: G protein coupled surface receptor that mediates acetylcholine action on smooth and cardiac muscle and in CNS; may be linked to a potassium channel (membrane polarization) or second messenger systems.