EFFECTS OF FLUMAZENIL ON RECOVERY SLEEP AND HORMONAL SECRETION AFTER SLEEP-DEPRIVATION IN MALE CONTROLS

The effects of flumazenil, a benzodiazepine antagonist, on the sleep e lectroencephalogram (EEG) and neuroendocrine secretion in early mornin g recovery sleep (0500-0800 hours) following sleep deprivation (SD; 23 00-0500 hours) were studied in seven healthy men. SD induced an increa se in slow wave sleep (SWS), a decrease in sleep onset latency (SOL), an enhancement of EEG delta and theta power in non-rapid-eye-movement sleep, an increase in plasma human growth hormone (GH) concentration, and a decrease in plasma cortisol levels in recovery sleep (0500-0800 hours). Plasma GH, but neither plasma cortisol nor adrenocorticotrophi c hormone (ACTH) concentration was attenuated during SD as compared to sleep (2300-0445 hours). The administration of flumazenil (3 x 1 mg i ntravenously) during recovery sleep resulted in an inhibition in SWS, an increase in stage 2 sleep, a selective reduction in delta and theta power, and a tendency to prolongation of SOL. Plasma GH concentration was decreased but plasma cortisol and ACTH remained unaffected. Since the SD-induced changes in sleep EEG and plasma GH secretion were anta gonized by flumazenil, it is suggested that electrophysiological and h ormonal effects of SD are mediated at least in part through GABAergic mechanisms.