title: Diurnal rhythm disorder of behavioral activity in SAMP1 mice is partially normalized by spontaneous wheel running.
abstract: We examined the diurnal rhythms of food and water intake, spontaneous wheel running (SWR), and spontaneous motor activity (SMA) in the SAMP1 strain, a mouse model of accelerated senescence. Without SWR exercise, food, and water intake in the SAMP1 mice was significantly higher during the light (L)-phase of the light-darkness (LD) cycle than in the control SAMR1 strain. Additionally, SWR and SMA activity rhythms were split in SAMP1 mice, as demonstrated by the appearance of a secondary peak starting from the end of the dark (D)-phase. SWR exercise significantly increased the percentages of nocturnal food and water intake and SMA in the SAMP1 mice, although food and water intake did not reach the level of control SAMR1 mice. Thus, the disordered diurnal rhythms in SAMP1 mice can be normalized, even if only partially, by SWR exercise.
authors.affiliation: Department of Sports Medical Science, Institute on Aging and Adaptation, Shinshu University Graduate School of Medicine, Matsumoto 390-8621, Japan. yanagi@sch.md.shinshu-u.ac.jp
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Yanagidaira
authors.forename: Keiichi
authors.initials: K
authors.lastname: Higuchi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nose
mesh_terms: D000375:Aging; D000704:Analysis of Variance; D000818:Animals; D021081:Chronobiology Disorders / Q000503:physiopathology* / Q000534:rehabilitation*; D003624:Darkness; D004326:Drinking; D004435:Eating; D005260:Female; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D008817:Mice, Mutant Strains / Q000235:genetics; D023421:Models, Animal; D009043:Motor Activity; D017440:Photoperiod; D010805:Physical Conditioning, Animal; D012420:Running; D013997:Time Factors