Ginkgo biloba extract EGb 761 attenuates hippocampal neuronal loss and cognitive dysfunction resulting from chronic restraint stress in ovariectomized rats

Laboratory of Neuropsychopharmacology, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
Neuroscience (Impact Factor: 3.36). 11/2007; 149(2):256-62. DOI: 10.1016/j.neuroscience.2007.07.042
Source: PubMed


We have recently found that a combination of ovariectomy (OVX) and chronic restraint stress causes cognitive dysfunction and reduces hippocampal CA3 neurons in female rats and that estrogen replacement suppresses the OVX/stress-induced behavioral and morphological changes. In this study, we examined the effect of Ginkgo biloba extract (EGb 761), a popular herbal supplement, on the cognitive dysfunction and neuromorphological change in OVX/stress-subjected rats. Female Fisher 344 rats were randomly divided into three groups: vehicle-treated OVX, EGb 761 (50 mg/kg) -treated OVX and vehicle-treated sham-operated control groups. Two months after ovariectomy, all animals received restraint stress for 21 days (6 h/day), and were then subjected to a novel object recognition test followed by morphological examination by Nissl staining. EGb 761 was orally administered once daily until the behavioral analysis was done. Treatment with EGb 761 improved memory impairment and neuronal loss of hippocampus in the OVX/stress-subjected group in the same ways as 17beta-estradiol. On the other hand, EGb 761 did not affect the loss of bone mineral density and increase in body weight after OVX, although 17beta-estradiol attenuated them. These results have important implications for neuroprotective and cognition enhancing effects of EGb 761 in postmenopausal women and suggest that the effects are mediated by a different mechanism from estrogen.

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    Full-text · Article · Apr 2014 · Behavioural brain research
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    • "Restraint stress ICR mice were randomly divided into two groups: a restraint-stress group and a control group. Restraint stress was applied with a stainless mesh that allowed for a close fit to the mice for 3 h, as described previously (Takuma et al. 2007; Yun et al. 2010). Mifepristone, a GR antagonist (Sigma-Aldrich, St Louis, MO, USA), was injected i.p. at a dose of 25 mg/kg, 30 min before exposure to restraint stress. "
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    Full-text · Article · Sep 2012 · Journal of Neurochemistry
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    • "Takuma et al. [15] examined the effect of G. biloba extract (EGb 761) on cognitive dysfunction and neuromorphological change in ovariectomised (OVX)/stress subjected rats. Their results showed that treatment with EGb 761 improved memory impairment and neuronal loss of the hippocampus in the OVX/stress-subjected group in the same ways as 17-β-estradiol. "
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