Humoral Regulation of Sleep

Publisher Summary This chapter reviews that the growth hormone production and release (GHRH) /SRIF/GH axis, cholecystokinin (CCK), and, perhaps, other gastrointestinal (GI) hormones and the cytokine network are involved in non-rapid-eye-movement sleep (REMS) regulation. The data presented also indicate that the VIP/PHI/PRL axis is involved in rapid-eye-movement sleep (REMS) regulation. It is unlikely that these various systems act independently of each other about sleep regulation. The sleep activational system illustrates that biochemical cascades and feedback mechanisms act in concert to regulate sleep. It is emphasized that most data demonstrating the interactions shown are derived from experiments in which sleep was not measured and non-CNS systems are used. Sleep factors (SFs) are produced in several places in the body, and a certain degree of compartmentalization can be found. GHRH, VIP, and CRF are best characterized as hypothalamic releasing hormones, though they are found in other brain and body sites. They may act on somnogenic brain structures directly or by affecting the production of pituitary SFs (GH, PRL, and POMC derivatives); they may have indirect effects on sleep as well. Cytokines and circulating GI peptides are produced both inside and outside the brain.