Relationship between occurrence of tremor/convulsion and level of β-carbolines in the brain after administration of β-carbolines into mice

Abstract

Fifteen β-carboline derivatives, including those found in the South American hallucinogenic plant Banisteriopsis caapi, were injected IP and IVC into mice. Subsequent behavioral changes were observed and the levels of the compounds in brain tissue were determined. It was found that following IP administration, tremors and/or convulsions were induced by β-carbolines having aliphatic alkyl groups, but not by those with carbonyl and oxo groups substituted at carbon-1 of the C ring. These effects were potentiated by the presence of a methoxy group at carbon-7 of the A ring, and their durations of actions were prolonged by 3,4-dihydro derivatives. When induced, tremors/convulsions correlated with levels of β-carbolines in the brain. The smaller ED 50 values of β-carbolines that cause tremors/convulsions showed lower levels of β-carbolines in brain tissue.