Abstract: The mice given chronic unpredictable stress after ovariectomized was used to observe the effect of Cynomorium songaricum ethyl acetate extract(ECS)on cognitive dysfunction induced by chronic stress.The Morris water maze was applied to test the spatial learning and memory ability.Western blot assay was used to test the expression of Syn and PSD95 in the hippocampus.HE staining was used to observe morphological change of hippocampal neurons.The results showed that the explore time of targeted quadrant of mice from ECS group increased (P<0.01) in the Morris water maze test.In addition,ECS can improve the expression of Syn(P<0.05) and PSD-95(P<0.05)in Western blot assay.Compared with model group,the neurological form of pyramidal cells in hippocampus were improved by HE staining.Hippocampus nerve cell injury was improved.In conclusion,ECS can improve the expression of Syn and PSD95,protect hippocampus nerve cell and improve the cognitive dysfunction.

Key words: Cynomorium songaricum ethyl acetate extract, cognitive function, chronic stress, neuroprotection, Syn, PSD-95