Bufotenine (BUTN) is a hallucinogen with psychotropic effects. High levels of BUTN and its precursor, N-methylserotonin are shown for the first time to occur and to accumulate mainly in the brain during the degradation of serotonin in the central nervous system of the toad, Bufo bufo japonicus. These compounds are concentrated in the hindbrain, which includes the cerebellum and medulla...