Physostigmine (also known as eserine from éséré, West African name for the Calabarbean) is a parasympathomimetic, specifically, a reversible cholinesterase inhibitor
obtained from the Calabar bean. It can also be obtained from Streptomyces
griseofuscus . By interfering with the metabolism of acetylcholine, physostigmine
indirectly stimulates both nicotinic and muscarinic receptors. The chemical was
synthesized for the first time in 1935 by the chemists Percy Lavon Julian and Josef Pikl.
The drug, physostigmine, when administered to people by infusion in laboratory tests, aids and improves performance of everyday working memory. Working memory is the process which temporarily holds information such as a phone number until a person gets to a phone to dial the number.
Physostigmine is a short-acting drug that enhances levels of a substance (acetylcholine) between neurons in the brain. The drug improves efficiency and reduces the effort needed to perform working memory tasks while altering the activity of some of the brain regions activated by this memory task. The results of this study are reported in the June 10, 1997 issue of the Proceedings of the National Academy of Sciences.
Physostigmine is used to treat myasthenia gravis, glaucoma and delayed gastric emptying. Because it is a tertiary amine, it can cross the blood-brain barrier and so it is also used to treat the central nervous system effects of atropine, scopolamine and other anticholinergic drug overdoses. Possible side effects include depression, and overdose can cause a cholinergic syndrome. It is available in the U.S. under the trade names Antilirium, Eserine Salicylate, Isopto Eserine, and Eserine Sulfate. Physostigmine is also used in creating opiates, discovered by Ludwig Laqueur.