Effects of doxepin on spatial memory, TNF-α and Bcl-2 family genes expression in rat hippocampus

Introduction: Although the initial hypothesis for the action of doxepin was based on the inhibition of the reuptake of neurotransmitters, it has been suggested that it may also involve other mechanisms. Therefore, this study aims to investigate the effect of doxepin on spatial memory, tumor necrosis factor alpha (TNF-alpha) level, expression of pro-apoptotic (Bad and Bax) and anti-apoptotic (Bcl-2) genes in the rat hippocampus. Materials and Methods: Male rats were divided randomly into three groups; the control, the doxepin 1 and 5 mg/kg, respectively). Rats received i.p injection of doxepin for 21 days. Spatial memory was evaluated by Morris water maze test. Then the hippocampi were dissected for measurement of the expression of Bcl2, Bad and Bax genes and the TNF-alpha level. Results: Our results showed no significant effects of doxepin on spatial memory. Doxepin significantly decreased expression of Bad gene, but had no significant/considerable effects on Bcl2 and Bax gene expression. Also, the ratio of TNF-alpha to total protein (%) did not show significant differences in the rat hippocampus. Conclusion: These results did not show any significant impact of doxepin on the factors affecting the neuronal functions in intact animals. However, Since a significant reduction in the hippocampal Bad mRNA levels was observed It is our assumption that doxepin has neuroprotective effects.