Effect of Hypericum perforatum extract on consolidation of passive avoidance learning of acutely restrained male wistar rats

Ageing could been resulted to increase of oxidative stress that could lead to damage of brain processes including cognitive functions. Since Hypericum extract have decreasing effect on the stress, it’s effect on passive avoidance learning of restrained male wistar rats were examined.

Twenty-four male wistar rats, each weighing about 250-300 g were divided into four groups, control, immobility stress, immobility stress + Hypericum extract (animals administered with 350 mg/kg/day of Hypericum extract) and Hypericum extract group. All of groups had free access to water and food with no limitation. Hypericum extract was administrated orally as soluted in water each day for one week. The passive avoidance learning test was done in the shuttle box device following intending treatments for all groups and in similar conditions. In this test, increased time delay for the first time of entry to the dark chamber considered as improved passive avoidance learning. The data were analyzed by SPSS software and one-way ANOVA followed by the Tuckey test.

In compare to control group, passive avoidance indices were increased significantly. In other words, mean Step Through Latency (STL) of H. perforatum + stress group was 207 seconds and was higher than that of stress only group (150 seconds) significantly (p<. 001).Maximum acceptable STL has been considered as 300 seconds.

Our results indicated that administered Hypericum extract could increase passive avoidance learning indices in rats in model of immobility stress of male wistar rats.