Amanita muscaria (fly agaric): from a shamanistic hallucinogen to the search for acetylcholine

Introduction

Amanita muscaria (fly agaric) is presented as a culturally prominent and readily recognisable mushroom in Europe and the UK, notable for its scarlet cap with white scales and association with birch forests. Earlier research and ethnographic reports established its long-standing use as an inebriant and hallucinogen among Siberian shamans, while 19th- and 20th-century pharmacological work identified multiple bioactive alkaloids; nonetheless, the mushroom's precise contribution to understanding parasympathetic pharmacology and the identity of the endogenous parasympathetic transmitter remained a historically important puzzle. This paper traces that historical and pharmacological trajectory. It aims to recount the ethnographic accounts of shamanistic use, summarise the isolation and characterisation of the mushroom's active constituents (including muscarine, ibotenic acid, muscimol and muscazone), and to describe how those findings, together with work on other alkaloids such as pilocarpine and physostigmine, contributed to the discovery of acetylcholine and to the development of therapeutics for glaucoma and respiratory disease. The article is framed as a narrative historical review rather than an empirical study with a formal experimental protocol.