[Restoration of sleep in cats pretreated with tabernanthine p-chlorophenoxyacetate (SAD 103) (author's transl)]

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.