The actions of diazepam and gamma-hydroxybutyrate (GHB) were assessed on the sleep-wakefulness cycle of male Wistar rats.
One and 2 mg/kg diazepam and 12.5 mg/kg GHB had no effects on the sleep variables. After 25 mg/kg GHB, slow wave sleep (SWS2) was significantly increased. Following the combined administration of non-effective doses of GHB and diazepam, significantly higher amounts of SWS2 at the expense of wakefulness were obtained. The injection of a subconvulsant dose of bicuculline (2.5 mg/kg) prior to treatments which significantly increased SWS2 prevented this effect to show up.
It is suggested that the actions of GHB and diazepam on the sleepawake cycle are related to the same neurotransmitter system.