Hypnotic action of ethyl beta-carboline-3-carboxylate, a benzodiazepine receptor antagonist, in cats.

The present study demonstrates that ethyl beta-carboline-3-carboxylate (beta-CCE), a benzodiazepine receptor antagonist, has hypnotic and sedative actions in cats. Moreover, at a dose that does not by itself affect sleep, beta-CCE reverses the action of diazepam on sleep organization. The hypnotic effect of subcutaneous administration of beta-CCE (5 mg/kg) lasts for 3-4 h. During this period, deep slow wave sleep (deep non-REM sleep) and paradoxical sleep (REM sleep) significantly increase, while wakefulness markedly decreases. These results, which are quite opposite to the effects of benzodiazepines on sleep organization in cats, support the notion that beta-CCE also acts as a benzodiazepine antagonist of sleep organization.