Chronic unpredictable stress-induced reduction in the hippocampal brain-derived neurotrophic factor (BDNF) gene expression is antagonized by zinc treatment

Preclinical data indicate the antidepressant activity of zinc and the involvement of the brain-derived neurotrophic factor (bdnf) in this mechanism. the present study investigates the effect of chronic (16 days) combined treatment with zinc (15 mg/kg zinc hydroaspartate) and imipramine (5 mg/kg) in chronic unpredictable stress (cus) on the bdnf mrna level in the rat brain. moreover,serum zinc concentrations were also assessed. cus induced a significant reduction in the bdnf mrna level in the hippocampus by 21% but had no effect in the frontal cortex. repeated treatment with zinc induced a significant increase in the bdnf mrna level in the hippocampus in the unstressed animals by 12% and as in the chronically stressed animals by 14%,compared to the appropriate controls. imipramine treatment did not affect this factor. however,combined treatment of zinc and imipramine induced a 12% elevation of the bdnf mrna level in the stressed but not in the unstressed rats. cus induced a 19% reduction in the serum zinc concentration,whereas combined treatment of zinc and imipramine reduced this concentration by 24% in the unstressed and increased it (by 20%) in the stressed animals. these results indicate that: 1) cus induces a reduction in the bdnf gene expression with a concomitant diminution of serum zinc concentration and 2) the cus-induced reduction in the bdnf gene expression is antagonized by chronic treatment with zinc. copyright © 2011 by institute of pharmacology polish academy of sciences.