Muscimol

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 of the GABAA receptor.

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

Biology


Muscimol is produced naturally in the mushrooms Amanita muscaria, Amanita pantherina, and Amanita gemmata, along with muscarine, muscazone, and ibotenic acid. Of these, only A. muscaria and A. pantherina are safe for human consumption, the other being lethally poisonous in large doses. 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 GABAA 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 around 15-20mg for a normal person.

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.