 The major toxins involved in A. muscaria poisoning are muscimol ( 3 @-@ <unk> @-@ 5 @-@ <unk> @-@ 1 @-@ <unk> , an <unk> cyclic <unk> acid ) and the related amino acid ibotenic acid . Muscimol is the product of the <unk> ( usually by drying ) of ibotenic acid . Muscimol and ibotenic acid were discovered in the mid @-@ 20th century . Researchers in England , Japan , and Switzerland showed that the effects produced were due mainly to ibotenic acid and muscimol , not muscarine . These toxins are not distributed uniformly in the mushroom . Most are detected in the cap of the fruit , a moderate amount in the base , with the smallest amount in the stalk . Quite rapidly , between 20 and 90 minutes after ingestion , a substantial fraction of ibotenic acid is excreted <unk> in the urine of the consumer . Almost no muscimol is excreted when pure ibotenic acid is eaten , but muscimol is detectable in the urine after eating A. muscaria , which contains both ibotenic acid and muscimol . 
