Amanita muscaria (fly agaric): from a shamanistic hallucinogen to the search for acetylcholine.
The journal of the Royal College of Physicians of Edinburgh March 1, 2018 M R Lee, E Dukan, I Milne 29 citations
The fly agaric mushroom contains four hallucinogens: muscarine, muscimol, muscazone, and ibotenic acid. In 1912, Henry Dale hypothesized that muscarine or a similar substance was the neurotransmitter at parasympathetic nerve endings, but he and Otto Loewi later isolated the actual transmitter and showed it was acetylcholine, not muscarine. The receptor is now called cholinergic or muscarinic. This discovery led to valuable drugs: pilocarpine for glaucoma and ipratropium for lung diseases.