title: Immediate and delayed anxiety- and depression-like profiles in the adolescent Wistar-Kyoto rat model of endogenous depression following postweaning social isolation.
abstract: In order to understand links that exist between inherited risk or predisposition, brain and behavioural development, endocrine regulation and social/environmental stimuli, animal models are crucial. The Wistar-Kyoto (WKY) rat has been shown to have validity as a model of adult and adolescent depression. While sex- and age-specific differences in some of the face, predictive and construct validities of the model such as depression-like behaviours have been established, anhedonia and anxiety using other induced anxiety paradigms such as elevated plus maze remain equivocal. First, post-weaning social isolation effects on inherent and induced anxiety behaviours were tested during two critical time periods, early- and mid-adolescence. Isolation induced immediate effects on novel environment-induced hyperactivity and anxiety-related behaviours. Adolescent WKYs demonstrated reduced 50-kHz ultrasonic vocalizations suggesting agoraphobia-like behaviours. Second, isolated rats, despite being subsequently social-/group-housed demonstrated longer lasting effects on social interaction measures and anhedonia. This establishes that the depression-like profile observed during early- and mid-adolescence persists into late adolescence and early adulthood in WKY. Further, that interventions at a later stage during adolescence may not be able to reverse early adolescent effects in the context of pre-disposition, thus highlighting the irreversibility of being double-hit during critical time periods of brain and behavioural development and maturation.
authors.affiliation: Brain Research Laboratory, Biotechnology Unit, Department of Biosciences, Mangalore University, Mangalagangothri 574 199, Karnataka, India.
authors.forename: Reshma A
authors.initials: RA
authors.lastname: Shetty
authors.affiliation: Brain Research Laboratory, Biotechnology Unit, Department of Biosciences, Mangalore University, Mangalagangothri 574 199, Karnataka, India. Electronic address: monikasadananda@gmail.com.
authors.forename: Monika
authors.initials: M
authors.lastname: Sadananda
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D001007:Anxiety / Q000209:etiology* / Q000523:psychology; D001835:Body Weight / Q000502:physiology; D003866:Depressive Disorder / Q000209:etiology* / Q000523:psychology*; D004195:Disease Models, Animal; D005106:Exploratory Behavior; D005260:Female; D005518:Food Preferences; D005583:Fourier Analysis; D008297:Male; D018782:Maze Learning; D051381:Rats; D011920:Rats, Inbred WF; D012934:Social Isolation / Q000523:psychology*; D013550:Swimming / Q000523:psychology; D014828:Vocalization, Animal / Q000502:physiology
keywords: Adolescence; Anhedonia; Anxiety; Social interaction; WKY