Abstract

The relationships between the androgen receptors and cognitive processes in some brain regions such as hippocampus had been well documented in previous studies. The aim of this study was to evaluate the effect of bilateral intra-hippocampal infusion of modafinil on testosterone induced spatial learning alterations in the Morris water maze (MWM) and also the evaluation of the quantity of BrdU-positive cells in dentate gyrus as a marker of cell proliferation. Bilateral intra-hippocampal infusions (1 mu L/side) with different doses of testosterone enanthate (10, 50, and 100 mu g/side) or modafinil (50, 100, and 250 mu M/side) were performed, 30 min prior to training in MWM for four repeated days in male rats. Control groups received dimethyl sulfoxide (DMSO). The behavioural findings of this study, showed considerable raises in time and distance of reaching the hidden platform in testosterone (100 mu g/side) - treated animals, and also significant decreases in above mentioned parameters in modafinil (100 mu M/side) treated group compared to their related control groups. We also assessed the effects of modafinil (50, 100, and 250 mu M/side) plus testosterone enanthate (100 mu g/side), on the spatial learning in MWM and the effect on neurogenesis by recording BrdU-positive in all above mentioned groups. Final results of this study showed that modafinil (100 mu M/side) prevented the testosterone (100 mu g/side) - induced spatial learning deficits in MWM and also increased the quantity of BrdU-positive cells in dentate gyro in combination evaluations in comparison with testosterone - treated animals.