Vitex Agnus Castus extract improves learning and memory and increases the transcription of estrogen receptor alpha in hippocampus of ovariectomized rats

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 hormone-dependent 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 micro g/kg of estradiol valerat. Step-through passive avoidance [STPA] test was used for the evaluation of learning and memory. The hippocampal estrogen receptor alpha [ERalpha] expression was measured using Real-Time PCR

Results: The results demonstrated that VAC extract or estradiol had better performance on step-through passive avoidance test than control group [all P<0.05]. Moreover, administration of either estradiol or VAC extract increased the hippocampal mRNA level of ER alpha 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 ER alpha gene expression in the hippocampal formation

Heart rate variability and QT dispersion study in brain death patients and comatose patients with normal brainstem function

To compare heart rate variability [HRV] and QT dispersion in comatose patients with normal brainstem function and with brain death. Cross-sectional comparative study. The Intensive Care Unit of Ali-Ebn-Abitaleb Hospital, Rafsanjan Medical University from September 2007 to June 2009. Fourteen brain death patients with clinical signs of imminent brain death and 15 comatose patients were examined by neurologist in intensive care unit. HRV, RR interval and QT dispersion on ECG were assessed for 24 hours in both groups. Independent t-test and chi-square test were for statistical analysis to determine significance which was set at p< 0.05. According to Holter Findings, mean of standard deviation of RR-interval in the comatose and brain death groups was 48.33 and 35 respectively [p= 0.045]. Mean of covariance coefficient of RR-interval was 0.065 in the comatose group and 0.043 in the brain deaths [p= 0.006]. QT dispersion was not significant difference in two groups. HRV and RR-interval analysis appeared as an early finding for the diagnosis of brainstem death in comparison to comatose patients with normal brainstem function. QT dispersion had not significant in this regard