The effects of intrahippocampal testosterone and flutamide on spatial localization in the Morris water maze

Abstract

The high density of the androgen receptors in fundamental centers of learning and memory, such as hippocampus, shows that there must be some relationships between the androgen receptors and cognitive aspects. To determine the role of hippocampal androgen receptors in spatial learning, the current research has been conducted to assess the effect of testosterone enanthate, as the agonist, and flutamide, as the antagonist, of these receptors on spatial discrimination of rats, using the Morris water maze (MWM). Adult male rats were bilaterally cannulated into the CA1 region of their hippocampus. Different groups received different doses of flutamide (2, 5, 10 and 20 microg/0.5 microl) or testosterone enanthate (20, 40 and 80 microg/0.5 microl) through the cannulas 30 min before training for 3 days. The results showed dose-dependent increases in latencies and traveled distances to find the invisible platform both in flutamide- and testosterone-treated groups as compared to the control group, with peak effects at doses of 5 microg/0.5 microl for flutamide and 80 microg/0.5 microl for testosterone. Therefore, it seems that both androgen receptor blockade and exogenous testosterone can effect spatial localization of adult, male rats.