Muscarine (MCN)

Muscarine is a natural product found in certain mushrooms, particularly in Inocybe and Clitocybe species, such as the deadly C. dealbata. Mushrooms in the genera Entoloma and Mycena have also been found to contain levels of muscarine which can be dangerous if ingested. Muscarine has been found in harmless trace amounts in Boletus, Hygrocybe, Lactarius and Russula. Muscarine is only a trace compound in the fly agaric Amanita muscaria; the pharmacologically more relevant compound from this mushroom is muscimol. Muscarine mimics the action of the neurotransmitter acetylcholine by binding muscarinic acetylcholine receptors. These receptors were named after muscarine. There are 5 different types of muscarinic receptors; M1 - M5, and most tissues express a mixture of subtypes. The M2 and M3 subtypes mediate muscarinic responses at peripheral autonomic tissues.