PROOPIOMELANOCORTIN (POMC)-DERIVED PEPTIDES AND SLEEP IN THE RAT .1. HYPNOGENIC PROPERTIES OF ACTH DERIVATIVES

The sleep-wake effects of the proopiomelanocortin (POMC)-derived peptides, i.c.v. injected, are reported. Adrenocorticotropic hormone (ACTH, 1 μg) induces an awakening effect, while its two derivatives, desacetyl-α-MSH (des-α-MSH, 1 ng) and corticotropin-like intermediate lobe peptide (CLIP, 10 ng), are respectively able to increase slow wave sleep (SWS) and paradoxical sleep (PS); the hypnogenic effect of CLIP is also observed in hypophysectomized rats. Furthermore, two hypothalamic factors known to be involved in the control of POMC derivatives were also injected; MSH Inhibiting Factor (MIF) does not influence the viligance states, while Corticotropin Releasing Factor (CRF, 1 μg) increases the waking state. Finally, some preliminary results, obtained with a restraint stress and suggesting a possible interrelation between stress, sleep and POMC derivatives, are discussed. © 1990.