title: Alteration in plasma corticosterone levels following long term oral administration of lead produces depression like symptoms in rats.
abstract: Lead toxicity is known to induce a broad range of physiological, biochemical and behavioral dysfunctions that may result in adverse effects on several organs, including the central nervous system. Long-term exposure to low levels of lead (Pb(2+)) has been shown to produce behavioral deficits in rodents and humans by affecting hypothalamic-pituitary-adrenal (HPA) axis. These deficits are thought to be associated with altered brain monoamine neurotransmission and due to changes in glucocorticoids levels. This study was designed to investigate the effects of Pb(2+)exposure on growth rate, locomotor activity, anxiety, depression, plasma corticosterone and brain serotonin (5-HT) levels in rats. Rats were exposed to lead in drinking water (500 ppm; lead acetate) for 5 weeks. The assessment of depression was done using the forced swimming test (FST). Estimation of brain 5-HT was determined by high-performance liquid chromatography with electrochemical detection. Plasma corticosterone was determined by spectrofluorimetric method. The present study showed that long term exposure to Pb(2+) significantly decreased the food intake followed by the decrease in growth rate in Pb(2+)exposed rats as compared to control group. No significant changes in open field activity were observed following Pb(2+)exposure while significant increase in anxiogenic effect was observed. Increased plasma corticosterone and decreased 5-HT levels were exhibited by Pb(2+)exposed rats as compared to controls. A significant increase in depressive like symptoms was exhibited by Pb(2+)exposed rats as compared to control rats. The results are discussed in the context of Pb(2+) inducing a stress-like response in rats leading to changes in plasma corticosterone and brain 5-HT levels via altering tryptophan pyrrolase activity.
authors: Department of Biochemistry, Neurochemistry and Biochemical Neuropharmacology Research Unit, University of Karachi, Karachi, Pakistan. saida-h1@hotmail.com
authors: Saida
authors: S
authors: Haider
authors: Sadia
authors: S
authors: Saleem
authors: Saiqa
authors: S
authors: Tabassum
authors: Saima
authors: S
authors: Khaliq
authors: Saima
authors: S
authors: Shamim
authors: Zehra
authors: Z
authors: Batool
authors: Tahira
authors: T
authors: Parveen
authors: Qurat-ul-ain
authors: QU
authors: Inam
authors: Darakhshan J
authors: DJ
authors: Haleem
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects; D003345:Corticosterone / Q000097:blood*; D003863:Depression / Q000097:blood* / Q000139:chemically induced; D004435:Eating / Q000187:drug effects; D007854:Lead / Q000633:toxicity*; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000032:analysis; D013550:Swimming
chemical_list: D007854:Lead; D012701:Serotonin; D003345:Corticosterone