Effects of doxepin on gene expressions of Bcl-2 family, TNF-α, MAP kinase 14, and Akt1 in the hippocampus of rats exposed to stress.

Stress is one of the effective factors in the development of depressive disorders that performs some parts of its effects by affecting hippocampus. Since doxepin has been shown to have neuroprotective effects, in this study, we focused on the effects of doxepin on the expression of involved genes in neuronal survival and plasticity in the rat hippocampus following chronic stress. Male Wistar rats were divided into four groups, the control, the stress, the stress-doxepin 1 mg/kg and the stress-doxepin 5 mg/kg, respectively. To induce stress, the rats were placed within adjustable restraint chambers for 6 h/day, for 21 days. Before daily induction of the stress, rats received an i.p. injection of doxepin. At the end of experiments, expression of Bax, Bad, Bcl-2, tumor necrosis factor alpha (TNF-α), mitogen-activated protein kinase 14 (MAPK14) and serine-threonine protein kinase AKT1 genes were detected by reverse transcription polymerase chain reaction (RT-PCR) in the hippocampus. Results showed significant enhancements in expression of Bax, Bad and Bcl-2 genes in the stressed rats, whereas expression of TNF-α, MAPK14, and AKT1 genes didn't show significant differences. Doxepin could decrease the expression of Bax and Bad genes in the stress group, but had no significant effects on the expression of other genes. The present findings indicated that doxepin can probably change the pattern of gene expression in the hippocampus to maintain neurons against destructive effects of stress.