The effect of intrahippocampal injection of testosterone enanthate (an androgen receptor agonist) and anisomycin (protein synthesis inhibitor) on spatial learning and memory in adult, male rats

In most mammals, the hippocampus has a well-documented role in spatial memory acquisition. High concentration of androgen receptors in fundamental centers of learning and memory in brain such as hippocampus shows that there may be some relationships between androgen receptors and cognitive aspects of brain. Previous studies, which have shown sex-dependent differences in hippocampal morphology and physiology, suggest a modulatory role for sex steroids in hippocampal function. Androgens have been shown to modulate some hippocampal-mediated behaviors including learning and memory. To study the mechanism of action of androgens in processes underlying learning and memory, anisomycin, a protein synthesis inhibitor was used to prevent the genomic effects of testosterone. Therefore, the effects of anisomycin and testosterone together were assessed on rat's performance in MWM. Rats received anisomycin (2.5 μg/0.5 μl), testosterone (80 μg/0.5 μl) or both anisomycin (2.5 μg/0.5 μl) and testosterone (80 μg/0.5 μl) through the connulas in the CA1 region. Anisomycin was injected 20 min and testosterone was injected 35 min before training each day. The results showed that anisomycin (2.5 μg/0.5 μl) and testosterone (80 μg/0.5 μl) increased latencies to find the invisible platform. But the group that received testosterone and anisomycin together was decrease in latency and traveled distance to find the invisible platform.