Ethyl beta-carboline-3-carboxylate antagonizes the action of GABA and benzodiazepines in the hippocampus.

In urethane-anaesthetized rats, the beta-carboline derivative beta CCE (0.3-1.0 mg/kg i.v.) excited hippocampal pyramidal cells which were inhibited by GABA (applied iontophoretically) and benzodiazepines (applied iontophoretically or intravenously). While benzodiazepines facilitated the action of GABA, the effects of GABA and benzodiazepines were antagonized by beta CCE. This electrophysiological study supports the behavioural observations that beta CCE is a benzodiazepine receptor antagonist.