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Objective:To explore the effects of chronic restraint stress (CRS) on the abilities of spatial learning and memory and the levels of excitatory amino acids in the hippocampal dentate gyrus (DG) in the old rats,and to investigate the neurochemical mechanism of CRS in affecting the spatial learning and memory abilities.Methods:Sixteen male SD rats (18 months old) were randomly divided into control group (n =8) and CRS group (n=8),and the rats in CRS group received CRS 2 h every day for 30 d.And then the spatial learning and memory abilities of rats were measured by Morris water maze (MWM) test,and the extracellular levels of excitatory amino acids including asparate (Asp) and glutamate (Glu) in the DG were simultaneously determined by in vivo microdialysis and HPLC.The levels of corticosterone (CORT) and epinephrine (EPI) in serum of the rats wereexamined by ELISA assay.Results:In CRS group,the escape latencies on the 2nd-4th days were significantly increased and the percentage of time spent in target quadrant on the 5th day was markedly decreased in MWM test compared with control group (P＜0.05).Compared with before training,the extracelluar level of Asp in the DG in control group was significantly increased on the 2nd day in MWM test;compared with control group,the extracelluar level of Asp in the DG in CRS group was significantly decreased on the 3rd day in MWM test (P＜0.05).Compared with before training,the Glu levels in the DG in MWM test in both control and CRS groups were markedly increased (P＜0.05),but there was no significant difference between two groups (P＞0.05).Compared with control group,the levels of CORT and EPI in the serum of the rats in CRS group were significantly increased (P＜0.05).Conclusion:CRS impairs the spatial learning and memory abilities in the old rats,which may be related to the decrease of Asp level in the hippicampal DG of the rats.
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Objective To observe the extracellular content of dopamine (DA)and expression of D1 receptors in hippocampal dentage gyrus (DG)in the model rats with vascular dementia (VD),and to investigate the relationship between them.Methods 12 male SD rats were randomly divided VD group and sham-operation group,and the VD model was prepared by permanent bilateral carotid occlusion.The extracellular content of DA in the DG was determined by in vivo microdialysis and HPLC,and the expression of D1 receptors was measured by immunehisto-chemistry.Results The DA content in the DG of the rats in VD group was lower than that in sham-operation group (P 0.05).Conclusion The DA content in the hippocampal DG is decreased in the VD rats,and its function may be compensated by the up-regulation of D1 receptors in the DG hilus.
RESUMEN
In this study,cholesterol content of fresh water fish oil emulsion was determined by gas chromatography. It was 30g/L and was lower than that in other marine fish oil preparations. The regression equation of standard curve was Y=1. 855x-6. 3467 ,and correlation coefficient was 0. 9990. The recovery rate ranged from 84.0% to 97. 0% ,and CV = 7.1%.