title: Paradoxical sleep deprivation facilitates subsequent corticosterone response to a mild stressor in rats.
abstract: The pituitary-adrenal responsiveness to a mild stressor was assessed in rats that were deprived of paradoxical sleep (PS) and in controls that were not deprived. Animals were either individually- or group-deprived for 96 h and hormone levels were assessed at 0, 5, 20 or 60 min after a saline injection+novelty and compared with rats which were not deprived. Both types of PS deprivation resulted in elevated adrenocorticotropin levels at 0 min, which peaked at 5 min in all animals. Individually-deprived rats exhibited the highest corticosterone (CORT) levels at 0 min. Peak levels were higher and occurred earlier in PS-deprived than in control rats (5 vs. 20 min, respectively). At 20 min, CORT levels had already returned to unstressed levels in PS-deprived rats, but not in control rats. These data indicate that PS deprivation induces facilitation of the adrenocortical response to a mild stressor, but do not suggest that PS deprivation changes the negative feedback sensitivity to CORT.
authors.affiliation: Department of Psychobiology, Universidade Federal de São Paulo, Rua Napoleão de Barros, 925, São Paulo, SP 04024-002, Brazil. suchecki@psicobio.epm.br
authors.forename: Deborah
authors.initials: D
authors.lastname: Suchecki
authors.forename: Paula A
authors.initials: PA
authors.lastname: Tiba
authors.forename: Sergio
authors.initials: S
authors.lastname: Tufik
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000097:blood* / Q000378:metabolism; D000818:Animals; D003345:Corticosterone / Q000097:blood* / Q000378:metabolism; D005246:Feedback / Q000502:physiology*; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism*; D008297:Male; D008959:Models, Neurological; D010913:Pituitary-Adrenal System / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012892:Sleep Deprivation / Q000097:blood* / Q000503:physiopathology; D013312:Stress, Physiological / Q000097:blood* / Q000503:physiopathology; D015854:Up-Regulation / Q000502:physiology
chemical_list: D000324:Adrenocorticotropic Hormone; D003345:Corticosterone