title: Late feeding in the active period decreases slow-wave activity.
abstract: OBJECTIVE
  Sleep and feeding behaviors closely interact to maintain energy homeostasis. While it is known that sleep disorders can lead to various metabolic issues such as insulin resistance, the mechanism for this effect is poorly understood. We thus investigated whether different feeding rhythms during the active period affect sleep-wake regulation.
  
  
  METHODS
  For 2weeks, mice were randomly assigned to 1 of 3 feeding schedules as follows: free access to lab chow during the active period (ZT12-24, Ad-lib group), free access to lab chow during the first half of the active period (ZT12-18; Morning group), or free access to lab chow during the second half of the active period (ZT18-24, Evening group). Food intake, body weight, body temperature, locomotor activity, and sleep were evaluated. The hypothalamus and cerebral cortex were examined post-mortem.
  
  
  RESULTS
  No alterations in food intake or body weight were observed among the 3 groups. The Evening group showed lower slow-wave activity (SWA) than the other 2 groups, in addition to higher expression of orexin mRNA in the hypothalamus and higher concentrations of dopamine and its metabolites in the cerebral cortex. AMPK phosphorylation was increased in the hypothalamus of mice in the Evening group; however, AMPK inhibition had no effect on SWA.
  
  
  CONCLUSIONS
  We concluded that late feeding reduces SWA in NREM sleep via a mechanism that involves orexin-mediated arousal in the hypothalamus and elevated monoamines in the cerebral cortex. These data have important implications for the relationship between sleep-wake disturbances and metabolic disorders.
authors.affiliation: Department of Integrative Physiology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima 770-8503, Japan; Student Lab, Faculty of Medicine, Tokushima University, Tokushima 770-8503, Japan; These authors contributed equally.
authors.forename: Kanna
authors.initials: K
authors.lastname: Oura
authors.affiliation: Department of Integrative Physiology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima 770-8503, Japan; These authors contributed equally.
authors.forename: Airi
authors.initials: A
authors.lastname: Otsuka
authors.affiliation: Department of Integrative Physiology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima 770-8503, Japan; PRESTO, JST, Kawaguchi 332-0012, Japan. Electronic address: shiuchi@tokushima-u.ac.jp.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Shiuchi
authors.affiliation: Department of Integrative Physiology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima 770-8503, Japan.
authors.forename: Sachiko
authors.initials: S
authors.lastname: Chikahisa
authors.affiliation: Department of Integrative Physiology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima 770-8503, Japan.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Shimizu
authors.affiliation: Department of Integrative Physiology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima 770-8503, Japan.
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Séi
mesh_terms: D000263:Adenylate Kinase / Q000378:metabolism; D000818:Animals; D015306:Biogenic Monoamines / Q000378:metabolism; D001831:Body Temperature; D001835:Body Weight; D004734:Energy Metabolism; D005247:Feeding Behavior / Q000502:physiology*; D015870:Gene Expression; D006706:Homeostasis; D007031:Hypothalamus / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009043:Motor Activity; D010766:Phosphorylation; D012890:Sleep / Q000502:physiology; D012892:Sleep Deprivation
chemical_list: D015306:Biogenic Monoamines; D000263:Adenylate Kinase
keywords: AMPK; Arousal; Feeding rhythm; Orexin; Sleep