Vitex Agnus Castus Extract Improves Learning and Memory and Increases the Transcription of Estrogen Receptor α in Hippocampus of Ovariectomized Rats

introduction: lower level of estrogen hormone is considered as an important factor for loss oflearning and memory in postmenopausal women. although estrogen replacement therapy is usedfor compensation, but long-term usage of estrogen is associated with a higher risk of hormonedependentcancers. phytoestrogens, due to fewer side effects, have been proposed to preventmenopause-related cognitive decline. methods: 24 female wistar rats weighing 180-220 g were used in this study. the animals wereovariectomized and randomly divided into four groups including, control and two groups whichreceived 8 and 80 mg/kg vitex agnus castus (vac) ethanolic extract orally. the last groupswere treated with 40 μg/kg of estradiol valerat. step-through passive avoidance (stpa) test wasused for the evaluation of learning and memory. the hippocampal estrogen receptor α (erα)expression was measured using real-time pcr. results: the results demonstrated that vac extract or estradiol had better performance on stepthroughpassive avoidance test than control group (all p<0.05). moreover, administration ofeither estradiol or vac extract increased the hippocampal mrna level of erα and preventedthe decrease in uterine weight of ovariectomized rats. discussion: based on our data, vac extract improves learning and memory in ovariectomizedrats. the positive effect of vac extract on learning and memory is possibly associated with anincrease in erα gene expression in the hippocampal formation.