ABSTRACT
       Background and Objectives: Hippocampus is the main structure involved in spatial learning and memory consolidation. Formation of spatial memory can be strongly influenced by medications, hormones and different substances. Due to importance of new pharmacotherapy on drug administration in pregnancy, the aim of this study was to investigate the effect of letrozole-therapy during pregnancy on memory and learning in offspring rats.
       Methods: In this study, 24 pregnant rats were divided into a control and three experimental groups (N=6). The subjects received low dose (0.25 mg/Kg), average dose (0.5 mg/Kg) and high dose (1 mg/Kg) of letrozole orally during 16-19 days of gestation. After maturating, learning and memory of the offspring were assessed by passive avoidance learning apparatus. Data were analyzed by SPSS 20 using one-way analysis of variance and the Tukey's test. P-values less than 0.05 were considered statistically significant.
         Results: Weights of the offspring who received letrozole decreased significantly compared with the control. There was no significant difference in the step-through latency between the experimental groups. However, the step-through latency and time spent in the dark compartment decreased significantly in the experimental groups compared with control group (P<0.05).
          Conclusion: The results of this study show that letrozole can influence learning and memory of offspring rats.
          Keywords: Letrozole, Gestation, Memory, Learning, Offspring, Rats.