Exposure to Enriched Environment Restores the mRNA Expression of Mineralocorticoid and Glucocorticoid Receptors in the Hippocampus and Ameliorates Depressive-like Symptoms in Chronically Stressed Rats

Publisher: Bentham Science Publishers

E-ISSN: 1875-5739|8|4|286-293

ISSN: 1567-2026

Source: Current Neurovascular Research, Vol.8, Iss.4, 2011-11, pp. : 286-293

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Abstract

Chronic stress can cause emotional dysfunction, but exposure to an enriched environment (EE) can benefit emotional homeostasis. Recent studies have demonstrated that EE can ameliorate stress-induced depressive-like behaviors. Whether hypothalamic-pituitary-adrenal (HPA) axis activity and corticosteroid receptors are involved in these effects of EE is not known. In our current study, we examined HPA axis activity and hippocampal mineralocorticoid receptor/glucocorticoid receptor (MR/GR) mRNA levels following chronic stress in rats. Our study showed that stress reduced body weight, decreased sucrose intake and sucrose preference, and increased immobility in a forced swimming test. These effects were ameliorated by EE. Also we found that 21 days of restraint stress resulted in low HPA axis activity, and a reduction of MR mRNA and MR/GR ratio in the hippocampus of rats, which was restored by EE. Thus, our current results emphasizes the efficiency of EE in the amelioration of stress-induced decrease in the mRNA expression of MR and MR/GR ratio as well as behavioral depression, providing initial evidence for a possible mechanism by which an enriched environment can restore stress-induced deficits.