title: Inhibition of immobilization stress-induced anorexia, behavioral deficits, and plasma corticosterone secretion by injected leptin in rats.
abstract: Leptin, originally identified as an anti-obesity hormone, also has an important role in the regulation of mood and emotion. The present study was designed to monitor effects of injected leptin on immobilization stress-induced anorexia, behavioral deficits, and plasma corticosterone secretion in rats. Exposure to 2 h immobilization stress decreased food intake and body weight in saline-injected animals. Animals exposed to open field, elevated plus maze, and light-dark transition tests the day following immobilization exhibited anxiety-like behavior. Leptin injected at doses of 0.1 and 0.5 mg/kg also decreased food intake and body weight in unstressed animals and elicited anxiolytic effects at dose of 0.5 mg/kg, monitored on the following day. Immobilization-induced decreases in food intake, body weight, as well as stress-induced behavioral deficits in the open field, elevated plus maze, and light-dark transition test were reversed by exogenous leptin in a dose-dependent (0.1-0.5 mg/kg) manner. Acute exposure to 2 h immobilization produced a fourfold rise in plasma levels of corticosterone. Animals injected with leptin at a dose of 0.1 mg/kg, but not at dose of 0.5 mg/kg, exhibited a marginal increase in plasma corticosterone. Immobilization-induced increases of plasma corticosterone were reversed by leptin injected at doses of 0.1 or 0.5 mg/kg. The data suggest that exogenous leptin can reduce stress perception, resulting in an inhibition of stress effects on the activity of hypothalamic-pituitary-adrenal axis and behavior. The reported pharmacological effects of leptin represent an innovative approach for the treatment of stress-related disorders.
authors.affiliation: Department of Biochemistry, Dow University of Health Sciences, Karachi, Pakistan.
authors.forename: Zeba
authors.initials: Z
authors.lastname: Haque
authors.forename: Nazia
authors.initials: N
authors.lastname: Akbar
authors.forename: Farzana
authors.initials: F
authors.lastname: Yasmin
authors.forename: Muhammad A
authors.initials: MA
authors.lastname: Haleem
authors.forename: Darakhshan J
authors.initials: DJ
authors.lastname: Haleem
mesh_terms: D000818:Animals; D000855:Anorexia / Q000097:blood / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control* / Q000523:psychology; D001522:Behavior, Animal / Q000187:drug effects*; D015415:Biomarkers / Q000097:blood; D001835:Body Weight / Q000187:drug effects; D003345:Corticosterone / Q000097:blood*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000187:drug effects; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D007274:Injections, Intraperitoneal; D020738:Leptin / Q000008:administration & dosage*; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D010913:Pituitary-Adrenal System / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D051381:Rats; D017208:Rats, Wistar; D012149:Restraint, Physical / Q000523:psychology*; D013315:Stress, Psychological / Q000097:blood / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control* / Q000523:psychology; D013997:Time Factors; D015854:Up-Regulation
chemical_list: D015415:Biomarkers; D020738:Leptin; D003345:Corticosterone