Blockade of 3-carbomethoxy-beta-carboline induced seizures by diazepam and the benzodiazepine antagonists, Ro 15-1788 and CGS 8216.

The benzodiazepine antagonists Ro 15-1788 and CGS 8216 blocked the clonic and tonic convulsions elicited by 3-carbomethoxy-beta-carboline (beta-CCM). The PD50 values for Ro 15-1788, CGS 8216, and diazepam were: 2.0, 0.6, and 2.0 mg/kg, respectively. Neither Ro 15-1788 nor CGS 8216 potentiated the effect of a threshold convulsant dose of beta-CCM. Moreover, these benzodiazepine antagonists neither attenuated nor potentiated the tremorigenic actions of another beta-carboline, harmaline. Diazepam, however, considerably reduced the tremorigenic actions of this drug.