Intrinsic and antagonistic effects of beta-carboline FG 7142 on behavioral and EEG actions of benzodiazepines and pentobarbital in cats.

The methyl-beta-carboline-3-carboxamide FG 7142 (10 mg/kg i.p.) produced a pronounced state of alertness, attentive behavior and fearfulness in the cat. Electroencephalographic (EEG) desynchronization in the cortex and theta rhythms in the hippocampus occurred concomitantly. Behavioral and hippocampal EEG actions of FG 7142 were reduced by Ro 15-1788 (10 mg/kg i.p.). The benzodiazepines diazepam and quazepam produced behavioral and EEG effects which were completely antagonized by FG 7142. The pentobarbital effects also were partially antagonized. These findings suggest that the cat provides an interesting model to study the anxiogenic properties of beta-carbolines.