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.

[Restoration of sleep in cats pretreated with tabernanthine p-chlorophenoxyacetate (SAD 103) (author's transl)]. / Le retour du sommeil chez le chat prétraité par le p-chlorophenoxyacetate de Tabernanthine (SAD 103).

The effects upon sleep returning after an effective dose of Tabernanthine p-chlorophenoxyacetate (SAD 103) are studied on chronically implanted cats. The near-total insomnia lasting for 6-8 h provoked by SAD is characterized by a calm waking period broken by periods of drowsiness. Recuperation follows a characteristic pattern: slow-wave sleep first reappears as phasic slow-wave sleep, the duration of the phases augmenting greatly between the 12th and 18th hour, after which slow-wave sleep reappears. After having been blocked for some 10 h, paradoxical sleep is seen again, remaining, however, as does slow-wave sleep, below normal for the first 30 h. The basic mechanisms behind the stimulating effect of SAD 103 are still unknown; hypotheses derived from recent neurophysiological and neurochemical investigations on sleep are discussed.