Influence of diazepam on different behavioral states of sleep-waking cycle.

Abstract

Diazepam is a widely used benzodiazepine. Their prolonged usage leads to deterioration of cognitive functions and to the reduction of the level of vigilance what is explained by hypnotic effect but not by anxiolytic action of this drug. The novelty of our investigation is the elucidation of whether diazepam produces slow wave sleep reduction likely to the other benzodiazepines and if so what is the bases of positive therapeutic effect of diazepam in insomniac patients. For this aim we decided the study of diazepam effects on the ultradian structure of sleep-waking cycle. On cats (n=5) metallic electrodes were implanted under Nembutal anesthesia. EEG registration lasting 12 hr daily started after animals' recovery. Diazepam was administered intraperitoneally (0.37; 0.75; 1.5; 2 mg/kg). Statistical processing was made by Students' t-test. Diazepam prolonged sleep onset latency and waking overall time. Incidence and overall percentage of deep slow wave sleep decreased significantly but doze dependently. Paradoxical sleep latency was also significantly increased after diazepam action. All dozes of drug used by us significantly decrease the duration of each episode of paradoxical sleep. Diazepam significantly increase incidence of paradoxical sleep episodes with maximal duration till to 5 min. Under the influence of diazepam paradoxical sleep coursed without emotional coloring, without any patterns reflecting the level of emotional tension during this phase. The first episode of paradoxical sleep with partial restoration of patterns of emotional tension developed after 9+/-2 postinjectional hours at the 2 mg/kg doze of diazepam. All parameters reflecting the level of emotional tension during paradoxical sleep wholly recovered after 27+/-2 hour of diazepam administration. Diazepam administration worsens the quality of slow wave sleep. It is suggested that positive therapeutic effect of this drug may be related with the reduction of emotional tension during paradoxical sleep and modulation of behavioral and EEG patterns of this behavioral state.