title: Anxiolytic-like effects of restraint during the dark cycle in adolescent mice.
abstract: Stress during developmental stage may cause psychological morbidities, and then the studies on stress are important in adolescent rodents. Restraint is used as a common stressor in rodents and the effects of restraint during the light cycle have been studied, but those of restraint during the dark cycle have not. The present study examined the effects of restraint during the light and dark cycles on anxiety behaviors in adolescent mice. Restraint for 3h during either the light or dark cycle impaired memory function in the fear conditioning test, but did not affect locomotor activity. In the elevated plus-maze test, restraint during the dark cycle reduced anxiety-like behaviors in mice. Repeated exposure to a 3-h period dark cycle restraint for 2 weeks had a similar anxiolytic-like effect. In contrast, restraint for 3h during the light cycle produced anxiety behavior in adolescent, but not adult, mice. The light cycle stress increased plasma corticosterone levels, and elevated c-Fos expression in the prefrontal cortex, paraventricular hypothalamic nucleus, basolateral amygdala and dentate gyrus, and enhanced serotonin turnover in the hippocampus and striatum, while the dark cycle stress did not. There was no difference in the stress-mediated reduction in pentobarbital-induced sleeping time between dark and light cycle restraint. These findings suggest that the anxiolytic effect of dark cycle restraint is mediated by corticosterone, serotonin or γ-aminobutyric acid-independent mechanisms, although the anxiogenic effect of light cycle restraint is associated with changes in plasma corticosterone levels and serotonin turnover in specific brain regions.
authors: Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan.
authors: Yuki
authors: Y
authors: Ota
authors: Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan.
authors: Yukio
authors: Y
authors: Ago
authors: Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan.
authors: Tatsunori
authors: T
authors: Tanaka
authors: Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan.
authors: Shigeru
authors: S
authors: Hasebe
authors: Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan.
authors: Yui
authors: Y
authors: Toratani
authors: Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan.
authors: Yusuke
authors: Y
authors: Onaka
authors: Laboratory of Molecular Neuropharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan; United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of Fukui, 2-2 Yamada-oka, Suita, Osaka 565-0871, Japan.
authors: Hitoshi
authors: H
authors: Hashimoto
authors: Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan; Department of Pharmacology, Graduate School of Dentistry, Osaka University, 1-8 Yamada-oka, Suita, Osaka 565-0871, Japan.
authors: Kazuhiro
authors: K
authors: Takuma
authors: Laboratory of Medicinal Pharmacology, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan; United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of Fukui, 2-2 Yamada-oka, Suita, Osaka 565-0871, Japan. Electronic address: matsuda@phs.osaka-u.ac.jp.
authors: Toshio
authors: T
authors: Matsuda
mesh_terms: D000375:Aging / Q000502:physiology* / Q000523:psychology*; D000818:Animals; D001007:Anxiety / Q000503:physiopathology* / Q000628:therapy; D001921:Brain / Q000378:metabolism; D003213:Conditioning, Psychological / Q000502:physiology; D003345:Corticosterone / Q000097:blood; D003624:Darkness; D005106:Exploratory Behavior / Q000502:physiology; D005239:Fear / Q000502:physiology; D006993:Hypnotics and Sedatives / Q000494:pharmacology; D008027:Light; D008297:Male; D051379:Mice; D009043:Motor Activity / Q000502:physiology; D010424:Pentobarbital / Q000494:pharmacology; D017440:Photoperiod; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D012149:Restraint, Physical / Q000502:physiology* / Q000523:psychology*; D012701:Serotonin / Q000378:metabolism; D012890:Sleep / Q000187:drug effects / Q000502:physiology
chemical_list: D006993:Hypnotics and Sedatives; D016760:Proto-Oncogene Proteins c-fos; D012701:Serotonin; D010424:Pentobarbital; D003345:Corticosterone
keywords: Anxiety behavior; Dark cycle; Light cycle; Restraint