The sleep modulating effects of peptides after sleep deprivation

A bidirectional interaction between sleep electroencephalogram (EEG) and endocrine activity is well established. A key role was shown for the reciprocal interaction between the sleep promoting growth hormone releasing hormone (GHRH) and the sleep impairing corticotropin releasing hormone (CRH) in male subjects. The influence of pulsatile administration of GHRH during the first few hours of the night suggests a sexual dimorphism. Sleep deprivation (SD) is strongly promoting sleep by increasing slow wave sleep (SWS) and rapid eye movement sleep (REMS). Aim: We performed a sleep-endocrine study in controls to investigate sleep-modulating influences of GHRH and CRH after SD. Gender and age were analysed as covariates. 48 normal subjects (age 19–69) were investigated during 4 consecutive nights. After one night of adaptation sleep EEG was recorded and hormone profiles of growth hormone (GH), cortisol and renin were collected simultaneously. This baseline night was followed by 40 hours of sleep deprivation. In the recovery night sleep-endocrine activity was retested and the subjects received between 2200 and 0100 hourly bolus injections of either placebo (PL), 4×50 ug CRH or 4×50 ug GHRH according to a randomised schedule. Sleep efficiency index (SEI), SWS, REMS and Non-REMS increased and wakefulness decreased after SD in each of the 3 treatments. The effect of GHRH on SEI and wakefulness was more distinct than after PL. The increase of REMS was highest after GHRH and lowest after CRH. In contrast to the influence of CRH on spontaneous sleep an additive effect of CRH and SD on the increase of SWS and the decrease of wakefulness was found. The increase of SWS was particularly distinct in females. Conclusions: Our data suggest that GHRH augments the sleep promotion after SD. In females CRH appears to enhance SWS.

Supported by a grant from the Deutsche Forschungsgemeinschaft (YA 12/1–2).