Zinc Chloride Reverse Influence on Dexamethasone Depressant Effects in Adult Male Rats

Cumulative evidence shows that dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is involved in the depressive disorders and natural or synthetic glucocorticoids have a direct effect on HPA activity. Considering the reports that show zinc deficiency is one of the causes of depressive-like behavior, the current study aimed to examine the effects of systemic injection of zinc chloride (ZnCl2) and/or dexamethasone sodium-phosphate (DEX) on depression in adult male rats. Different groups received ZnCl2 (2.5, 5, 10, and 20 mg/kg) and DEX (0.5, 1, 5, 10, and 30 mg/kg) and then depression was assessed in the forced swimming test (FST). Results showed that DEX 1 significantly increased, while DEX 30 and groups treated with zinc 10 mg/kg and zinc 20 mg/kg decreased total immobility time as compared to that of saline group. Also there was a significant decrease of total immobility time when zinc administered to rats already received DEX 1, compared with that of control group. The current study findings suggest that zinc has antidepressant effects dose dependently, while administration of DEX induced dual effects on depression; therefore, a low dose of DEX showed an increased level of depressive-like behavior while higher doses had antidepressant effects. Also, results showed that zinc administration could ameliorate depressive-like behavior induced via dexamethasone in FST.