Muscimol and ibotenic acid

What are Muscimol and Ibotenic Acid

Muscimol and Ibotenic Acid are the main psychoactive compounds present in many mushrooms of the Amanita genus. Muscimol and Ibotenic Acid are dissociatives and selective agonists for the GABAA receptor set, unlike Psilocybin, which is a psychedelic and an agonist for the 5-HT2A receptor set.

Chemical and physical properties

Muscimol is the product of the decarboxylation or drying of ibotenic acid and it is thought that muscimol is as much as ten times as potent as ibotenic acid.

Effects

The effects of muscimol are substantially different from psilocybin and psilocin, 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. The hallucinogenic effect produced by muscimol is most closely comparable to the hallucinogenic side effects produced by some other GABAergic drugs such as zolpidem.

Pharmacology, toxicity and general safety

Muscimol is a potent GABAA agonist, activating the receptor for the brain's major inhibitory neurotransmitter, GABA. Muscimol actually binds to the same site on the GABAA receptor complex as GABA itself, as opposed to other GABAergic drugs such as barbiturates and benzodiazepines which bind to separate regulatory sites. GABAA receptors are widely distributed in the brain, and so when muscimol is administered, it alters neuronal activity in multiple regions including the cerebral cortex, hippocampus, and cerebellum.

While muscimol is conventionally thought of as a selective GABAA agonist, it is also a potent partial agonist at the GABAC receptor, and so its range of effects results from a combined action at both targets.

In patients with Huntington's disease and chronic schizophrenia, oral doses of muscimol have been found to cause a rise of both prolactin and growth hormone.

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

The psychoactive dose of muscimol is around 10–15 mg for a normal person. A Guide to British Psilocybin Mushrooms by Richard Cooper published in 1977 recommends a smaller dose, 8.5 mg, and suggests that it is possible for this amount to be present in as little as 1 g of dried A. muscaria. A correct dose may be difficult to determine because potency varies dramatically from one mushroom to the next.

Musicmol's LD50 in mice is 3.8 mg/kg s.c, 2.5 mg/kg i.p.

Plants containing Muscimol and Ibotenic Acid

Muscimol is produced naturally in the mushrooms Amanita muscaria, Amanita pantherina, and Amanita gemmata, along with muscarine, muscazone, and ibotenic acid. A. muscaria and A. pantherina should be eaten with caution and prepared properly to lessen effects of nausea.; no official deaths from poisoning have been recorded from A. muscaria and A. pantherina. 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.