EVIDENCE FOR A SLEEP-PROMOTING INFLUENCE OF STRESS

In the present review the data supporting the existence at the central level of a stress-sleep relation are reported and discussed. An immob ilization stress of 1 or 2 hour(s) is accompanied by a marked polygrap hic waking and followed by a significant sleep rebound concerning main ly paradoxical sleep (PS). During the restraint, an important release of 5-hydroxyindoles [5-OHles, a good index of serotonin (5-HT) release ] occurs in the basal hypothalamus (BH). This release, produced by the nerve endings originating from the nucleus raphe dorsalis (nRD), migh t secondarily influence the release and/or the synthesis of hypnogenic substances directly involved in the sleep rebound production. Cortico tropin-like intermediate lobe peptide (CLIP, or ACTH(18-39)) is a pept ide possessing hypnogenic properties and derived from proopiomelanocor tin (POMC) whose perikarya are contained within the BH (arcuate nucleu s). The POMC nerve endings impinge on the nucleus raphe dorsalis, a st ructure containing sleep permissive components upon which CLIP acts to trigger sleep. It remains to be defined how the activity of the neuro nal loop described above is impaired under chronic stress conditions.