Effects of different doses of doxepin on passive avoidance learning in rats

Background: Studies have shown that Doxepin has anti-inflammatory effects and reduces oxidative stress. Due to the fact that other tricyclic antidepressants have been shown to have neuroprotective effects, this study aimed to investigate the effects of different doses of doxepin on passive avoidance learning in rats.

Materials and methods: Old male Wistar rats were used in this study. Doxepin was administered intraperitoneally (1, 5 and 10 mg/kg) for 21 days. Passive avoidance learning test was used for evaluation of learning and memory. Rats received foot electrical shock on fifteen day, and step through latencies were evaluated one week after the electrical shock in retention phase.

Results: Administration of Doxepin considerably increased the step through latencies in the rats that received the doses of 1 and 5 mg/kg (P < 0.05). However, in the dose of 10 mg/kg, there wasn't any significant change comparing to control group.

Conclusion: These results indicate that Doxepin has desirable effects on cognitive functions in low doses. Therefore, Doxepin can be considered as memory enhancers that understanding the underling mechanisms need further investigation.