Pathophysiology

Ibotenic acid is an agonist at central glutamic acid receptors; its decarboxylated derivative is an agonist at gamma-amino butyric acid receptors. Central effects of these hallucinogenic mushrooms are thought to be caused by these actions. Although muscarinic acid originally was isolated from A muscaria, the clinical syndrome does not suggest marked significance; in fact, anticholinergic findings may be observed. The psilocybin group contains the indoles psilocybin and psilocin. Psilocin and its phosphate ester, psilocybin, are similar in structure to lysergic acid diethylamide (LSD). They are structural analogues of serotonin (5-hydroxytryptamine); thus, hallucinogenic effects probably are mediated through effects on serotonergic receptors.