Introduction: Lower level of estrogen hormone is considered as an important factor for loss of
learning and memory in postmenopausal women. Although estrogen replacement therapy is used
for compensation, but long-term usage of estrogen is associated with a higher risk of hormonedependent
cancers. Phytoestrogens, due to fewer side effects, have been proposed to prevent
menopause-related cognitive decline.
Methods: 24 female Wistar rats weighing 180-220 g were used in this study. The animals were
ovariectomized and randomly divided into four groups including, control and two groups which
received 8 and 80 mg/kg Vitex agnus castus (VAC) ethanolic extract orally. The last groups
were treated with 40 μg/kg of estradiol valerat. Step-through passive avoidance (STPA) test was
used 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 stepthrough
passive avoidance test than control group (all P<0.05). Moreover, administration of
either estradiol or VAC extract increased the hippocampal mRNA level of ERα and prevented
the decrease in uterine weight of ovariectomized rats.
Discussion: Based on our data, VAC extract improves learning and memory in ovariectomized
rats. The positive effect of VAC extract on learning and memory is possibly associated with an
increase in ERα gene expression in the hippocampal formation.
Type of Study:
Original |
Subject:
Behavioral Neuroscience Received: 2015/02/23 | Accepted: 2015/05/19 | Published: 2015/07/1