title: Short photoperiod condition increases susceptibility to stress in adolescent male rats.
abstract: The seasonality of depressive symptoms is prevalent in children and adolescents. However, the mechanisms that underlie such susceptibility to seasonal influences on mood disorders are unclear. We examined the effects of a short photoperiod condition on the susceptibility to subchronic unpredictable mild stress (SCUS) and rhythmic alterations of plasma corticosterone (CORT), melatonin, and neuropeptide Y (NPY) in adolescent male rats. Compared with the 12h/12h light/dark photoperiod control (CON) rats, the 8h/16h photoperiod SCUS rats exhibited significant anhedonia, a core symptom of human depression, together with a blunted diurnal rhythm and elevation of 24h CORT, melatonin, and NPY levels. The 8h/16h photoperiod condition also blunted the rhythmicity of CORT, caused a phase inversion of melatonin, and caused a phase delay of NPY compared with 12h/12h CON rats. Such abnormalities of plasma CORT, NPY, and melatonin might cause adolescent individuals to present higher stress reactivity and greater vulnerability to stress over their lifetimes. The present study provides evidence of the susceptibility to the seasonality of stress-related disorders in adolescence.
authors.affiliation: National Institute on Drug Dependence, Peking University, Beijing 100191, China; Department of Pharmacology, Peking University, School of Basic Medical Science, Beijing 100191, China; Institute of Mental Health/Peking University Sixth Hospital and Key Laboratory of Mental Health, Ministry of Health, Beijing, China.
authors.forename: Ling-Zhi
authors.initials: LZ
authors.lastname: Xu
authors.affiliation: National Institute on Drug Dependence, Peking University, Beijing 100191, China.
authors.forename: Li-Jing
authors.initials: LJ
authors.lastname: Liu
authors.affiliation: National Institute on Drug Dependence, Peking University, Beijing 100191, China; Department of Pharmacology, Peking University, School of Basic Medical Science, Beijing 100191, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Yuan
authors.affiliation: National Institute on Drug Dependence, Peking University, Beijing 100191, China; Department of Pharmacology, Peking University, School of Basic Medical Science, Beijing 100191, China. Electronic address: li313@bjmu.edu.cn.
authors.forename: Su-Xia
authors.initials: SX
authors.lastname: Li
authors.affiliation: Department of Applied Social Sciences, City University of Hong Kong, Hong Kong, China.
authors.forename: Xiao-Dong
authors.initials: XD
authors.lastname: Yue
authors.affiliation: Department of Applied Social Sciences, City University of Hong Kong, Hong Kong, China.
authors.forename: Ju-Lian
authors.initials: JL
authors.lastname: Lai
authors.affiliation: National Institute on Drug Dependence, Peking University, Beijing 100191, China; Department of Pharmacology, Peking University, School of Basic Medical Science, Beijing 100191, China; Institute of Mental Health/Peking University Sixth Hospital and Key Laboratory of Mental Health, Ministry of Health, Beijing, China; Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Beijing, China. Electronic address: linlu@bjmu.edu.cn.
authors.forename: Lin
authors.initials: L
authors.lastname: Lu
mesh_terms: D000375:Aging / Q000097:blood / Q000523:psychology; D059445:Anhedonia / Q000502:physiology; D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology; D003345:Corticosterone / Q000097:blood; D004195:Disease Models, Animal; D004198:Disease Susceptibility; D008297:Male; D008550:Melatonin / Q000097:blood; D009478:Neuropeptide Y / Q000097:blood; D017440:Photoperiod; D017207:Rats, Sprague-Dawley; D055500:Resilience, Psychological; D016574:Seasonal Affective Disorder / Q000097:blood; D012621:Seasons; D013315:Stress, Psychological / Q000097:blood; D035501:Uncertainty
chemical_list: D009478:Neuropeptide Y; D008550:Melatonin; D003345:Corticosterone
keywords: Adolescence; Diurnal rhythm; Short photoperiod; Stress; Susceptibility