The effect of mental exercise and Nepeta menthoides on depression-like behavior induced by reserpine in the rat

Many studies demonstrate that cognitive empowerment reduces the risk of depression. Anti-depressant properties of Nepeta menthoides has also been reported. This study aimed to determine the effects of mental exercise and Nepeta menthoides and also to compare both of them on reserpine-induced depression in rats.

Male rats were divided into 8 groups: 1- Saline, 2- Reserpine, 3-Reserpine + Fluoxetine, 4- Nepeta, 5- Nepeta +Reserpine, 6- Mental exercise, 7- Mental exercise+ Reserpine, 8- Mental exercise + Nepeta + Reserpine. Reserpine was administered intraperitoneally at a dose of 0.2 mg/kg for 14 days. At the same time, the animals received Nepeta at a dose of 200 mg/kg and radial maze training was conducted. Then, the results for forced swimming test (FST), sucrose preference (SPT), elevated plus maze (EPMT) and open field tests (OFT) were assessed through one-way Analysis of Variance.

Reserpine significantly enhanced immobility and decreased active swimming time, while mental exercise combined with Nepeta were able to antagonize the effect of reserpine. Reserpine also lowered sucrose preference ratio which were recovered in mental exercise, Nepeta and combined treatment groups. Decreased locomotor activity due to reserpine was improved in mental exercise and Nepeta groups. Time spent and % of entrance into the open arms reduced by reserpine and Nepeta compensate it.

Mental exercise and Nepeta menthoides improve the depression and behavioral symptoms of anxiety induced by reserpine better than fluoxetine.