Muscimol

Template:Chembox new Muscimol (agarin, pantherine) is the major psychoactive alkaloid present in many mushrooms of the Amanita genus. Unlike psilocybin, a tryptamine, muscimol is a potent, selective agonist for one of the brain's primary neurotransmitters (GABA_A).

Chemistry

Muscimol is the product of the decarboxylation or drying of ibotenic acid.

Biology

File:Toadyone.jpg

Amanita muscaria, which contains muscimol

Muscimol is produced naturally in the mushrooms Amanita muscaria, Amanita pantherina, and Amanita gemmata, along with muscarine, muscazone, and ibotenic acid. However, the only mushroom amongst these that is safe for human consumption would be A. Muscaria, being as the other two are lethally poisonous. It is thought that, in A. muscaria, the layer just below the skin of the cap contains the highest amount of muscimol, and is therefore the most psychoactive portion.

Pharmacology

Muscimol is a potent GABA_A agonist, which is a receptor for the brain's major inhibitory neurotransmitter, GABA. The primary use for muscimol has become lab research, as the chemical essentially "turns off" part of the brain. When muscimol is administered, it has been shown active in the cerebral cortex, hippocampus, and cerebellum.

During a test involving rabbits connected to an EEG, muscimol showed a distinctly synchronized EEG tracing. This is substantially different from other indolic psychedelics, as brainwave patterns will generally show a desynchronization. In higher doses (2mg/kg), the EEG will show characteristic spikes.

When used in vivo, muscimol will pass through the human body, and be excreted (as muscimol) in the subject's urine.

The psychoactive dose of muscimol is 15-20mg.

Toxicity

LD50 mice: 3.8 mg/kg s.c, 2.5 mg/kg i.p.

LD50 rats: 4.5 mg/kg i.v, 45 mg/kg orally.

Effects

The effects of muscimol are substantially different from psilocybin, as the chemicals target separate parts of the brain. Muscimol has been shown to lack "structured" hallucinations in most cases, and the effects are frequently compared to a lucid dream state.

Synesthesia is also common, and increased sweating and salivation occurs from the action of another compound in the mushroom, muscarine.

See also

• Psychedelic drug
• Psychoactive drug

External links

• Psychoactive Amanitas on Erowid

References

• Merck Index, 12th Edition
• Ito Y, Segawa K, Fukuda H. 1995 "Functional diversity of GABAA receptor ligand-gated chloride channels in rat synaptoneurosomes" Synapse 19(3):188-96.
• Rätsch, Christian. (1998). The Encyclopedia of Psychoactive Plants. Rochester, VT: Park Street Press.
• Beaumont K, Chilton W. S., Yamamura H. I., Enna S. J. (1978). "Muscimol binding in rat brain: association with synaptic GABA receptors". Brain Res. 148 (1): 153–62. doi:10.1016/0006-8993(78)90385-2.{{cite journal}}: CS1 maint: multiple names: authors list (link)
• S. R. Snodgrass (1978). "Use of ³H-muscimol for GABA receptor studies". Nature. 273 (1): 392–394. doi:10.1038/273392a0.
• G. A. R. Johnston, D. R. Curtis, W. C. de Groat and A. W. Duggan (1968). "Central actions of ibotenic acid and muscimol". Biochemical Pharmacology. 17 (12): 2488–2489. doi:10.1016/0006-2952(68)90141-X.{{cite journal}}: CS1 maint: multiple names: authors list (link)