title: Waking and sleeping in the rat made obese through a high-fat hypercaloric diet.
abstract: Sleep restriction leads to metabolism dysregulation and to weight gain, which is apparently the consequence of an excessive caloric intake. On the other hand, obesity is associated with excessive daytime sleepiness in humans and promotes sleep in different rodent models of obesity. Since no consistent data on the wake-sleep (WS) pattern in diet-induced obesity rats are available, in the present study the effects on the WS cycle of the prolonged delivery of a high-fat hypercaloric (HC) diet leading to obesity were studied in Sprague-Dawley rats. The main findings are that animals kept under a HC diet for either four or eight weeks showed an overall decrease of time spent in wakefulness (Wake) and a clear Wake fragmentation when compared to animals kept under a normocaloric diet. The development of obesity was also accompanied with the occurrence of a larger daily amount of REM sleep (REMS). However, the capacity of HC animals to respond to a "Continuous darkness" exposure condition (obtained by extending the Dark period of the Light-Dark cycle to the following Light period) with an increase of Sequential REMS was dampened. The results of the present study indicate that if, on one hand, sleep curtailment promotes an excess of energy accumulation; on the other hand an over-exceeding energy accumulation depresses Wake. Thus, processes underlying energy homeostasis possibly interact with those underlying WS behavior, in order to optimize energy storage.
authors.affiliation: Department of Biomedical and NeuroMotor Sciences - Physiology, Alma Mater Studiorum - University of Bologna, Piazza di Porta San Donato 2, 40126 Bologna, Italy. Electronic address: marco.luppi@unibo.it.
authors.forename: Marco
authors.initials: M
authors.lastname: Luppi
authors.forename: Matteo
authors.initials: M
authors.lastname: Cerri
authors.forename: Davide
authors.initials: D
authors.lastname: Martelli
authors.forename: Domenico
authors.initials: D
authors.lastname: Tupone
authors.forename: Flavia
authors.initials: F
authors.lastname: Del Vecchio
authors.forename: Alessia
authors.initials: A
authors.lastname: Di Cristoforo
authors.forename: Emanuele
authors.initials: E
authors.lastname: Perez
authors.forename: Giovanni
authors.initials: G
authors.lastname: Zamboni
authors.forename: Roberto
authors.initials: R
authors.lastname: Amici
mesh_terms: D000818:Animals; D002540:Cerebral Cortex / Q000503:physiopathology; D002784:Cholesterol / Q000097:blood; D002940:Circadian Rhythm / Q000502:physiology*; D059305:Diet, High-Fat / Q000009:adverse effects*; D004569:Electroencephalography; D008297:Male; D009765:Obesity / Q000097:blood / Q000209:etiology / Q000503:physiopathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012890:Sleep / Q000502:physiology*; D014280:Triglycerides / Q000097:blood; D014851:Wakefulness / Q000502:physiology*
chemical_list: D014280:Triglycerides; D002784:Cholesterol
keywords: Continuous darkness; DD; HC; HCRT; High-fat hypercaloric diet; LD; LH; MA; NC; NREMS; OP; OR; Obesity; POA; REM sleep; REMS; Thy; WS; Wake; Wake–sleep cycle; continuous darkness; hypercaloric; hypocretinergic; hypothalamic temperature; lateral hypothalamus; light–dark; motor activity; nLab; non-REM sleep; normal laboratory conditions; normocaloric; obesity prone; obesity resistant; preoptic area; wakefulness; wake–sleep