The primary active chemicals known in Amanita muscaria and A.
pantherina are: Muscimol, Ibotenic Acid, Muscazone, and Muscarine.
Muscimol is considered the principle psychoactive, with oral dosages of
pure muscimol around 10-15 milligrams.1,2
Ibotenic acid is also active orally, but at doses 5-8 times higher than those of muscimol.2,3
The other chemicals are only present in trace amounts in the mushrooms,
well below their active levels in humans. The pharmacology of A.
muscaria is not fully understood, but the following chemicals are
considered the primary candidates:
: Muscimol's primary action is at GABA receptor sites as
a potent GABA-A agonist. Muscimol is commonly used in lab research on
the GABA, which is a primary inhibitory neurotransmitter. Muscimol has
been shown to be active in several parts of the brain including the
cerebral cortex, hippocampus, and cerebellum.4
: The current view is that some Ibotenic Acid does
cross the blood brain barrier unchanged, but some is partially
metabolised into muscimol and the rest excreted. Ibotenic acid,
however, has been shown to be a potent neurotoxin when injected
directly in the brains of mice and rats and is used as a potent
brain-lesioning agent. It is structurally similar to glutamate and
activates NMDA receptors, but this is not likely to be involved
significantly with the effects of A. muscaria.4,5
: Muscarine is known to affect acetylcholine levels and
acts at muscarinic receptors, named for this chemical. While the levels
of muscarine in A. muscaria are quite low (.002% - .003% by dry weight),5
some of the effects of A. muscaria are characteristic of cholinergic involvement.
: Muscazone is also a possible breakdown product of
Ibotenic Acid and Ott describes it as a possible "artifact of isolation
procedures" which is "of dubious psychoactivity". It is not considered
to be a substantial part of the psychoactive effects of A. muscaria.
: Several other chemicals have been reported in A. muscaria, some of them erroneously.
: One paper in 1953 (Wieland & Motzel)
claimed to find bufotenin in A. muscaria extract but all subsequent
research failed to confirm this result. Bufotenin is also not very
potent when taken orally. Bufotenin is not believed to be present in
the muscaria-class amanitas.
(isomer of atropine): One paper (Lewis 1955)
reported finding l-hyoscayamine in A. muscaria & A. pantherina from
South Africa, but subsequent researchers failed to confirm this
finding. This mistaken claim was repeated in the movie Altered States,
but all current references consider this an error.
: stizolobinic acid, stizolobic acid,
methyltetrahydrocarboline carboxylic acid. Isolated by some researchers
in some A. muscaria mushrooms, of unknown activity, but not considered
to be significant in the psychoactive effects of the muscaria mushrooms.
- Spinella, Marcello. "Psychopharmacology of Herbal Medicine" MIT Press, 2001. pp 386-390.
- Ott, Jonathan. "Pharmacotheon" Natural Products Co, 1996. pp 323-358.
- Schultes & Hofmann. "Botany & Chemistry of Hallucinogens" Charles C Thomas, 1980. pp 45-55.
- Olpe HR, Koella WP. (1978) The action of muscimol on neurones of the substantia nigra of the rat. Experientia 34: 235.
- Michelot D, Melendez-Howell LM. Amanita muscaria:
chemistry, biology, toxicology, and ethnomycology. Mycol Res. 2003.
107(2):131-146. [ Abstract ]
- Theobald W, Bush O, Kunz HA, Krupp P, Stenger EG,
Heimann H. 1968. "Pharmakologische und experimentalpsychologische
Untersuchungen mit 2 Inhaltsstoffen des Fleigenpilzes" Arzneim-Forsch
- Waser PG. "The pharmacology of A muscaria" In
Ethnopharmacologic Search for Psychoactive Drugs Efron DH, Homsted B,
Kline NS eds. 1967
- Chilton WS. 1975. "The course of an intentional poisoning" McIlvainea 2: 17-18
- Ito Y, Segawa K, Fukuda H. 1995 "Functional
diversity of GABAA receptor ligand-gated chloride channels in rat
synaptoneurosomes" Synapse 19(3):188-96.
- Eugster CH. 1968. "Wirkstoffe aus dem Fligenpilz" Naturwissenshaften, 55: 305-13.