Anastrozole improved testosterone-induced impairment acquisition of spatial learning and memory in the hippocampal CA1 region in adult male rats

Neurohormones like testosterone and estrogen have an important role in learning and memory. Many biological effects of androgens in the brain require the local conversion of these steroids to an estrogen. The current research has conducted to assess the effect of testosterone, estrogen and aromatase inhibitor (anastrozole) on spatial discrimination of rats, using Morris water maze and also the pathway of the effect of testosterone by using anastrozole. Adult male rats were bilaterally cannulated into CA I region of hippocampus and divided into 15 groups. Different groups received DMSO 0.5 mu l and DMSO 0.5 mu l + DMSO 0.5 mu l as control groups and different doses of testosterone enanthate (TE) (20, 40 and 80 mu g/0.5 mu l), estradiol valerat (EV) (1, 2.5, 5, 10, and 15 mu g/0.5 mu l), anastrozole (An) (0.25, 0.5, 1 mu g/0.5 mu l), TE 80 mu g/0.5 mu l + anastrozole 0.5 mu g/0.5 mu l and EV 15 mu g/0.5 mu l + anastrozole 0.5 mu g/0.5 mu l all days before training. TE and EV were injected 30-35 min before training and anastrozole was injected 25-30 min before training. Our results have shown both TE 80 mu g/0.5 mu l and EV 15 mu g/0.5 mu l groups increase in escape latency and traveled distance to find invisible platform. Also we have shown that anastrozole dose dependently decreases escape latency and traveled distance. We resulted that both TE and EN impaired acquisition of spatial learning and memory but anastrozole improved it. Anastrozole also could be buffered TE-induced impairment effect but not EV. (c) 2006 Elsevier B.V. All rights reserved.