Effect of Modified Sini Powder on nNOS Expression in Hippocampus of Rats with Psychological-Stress-Induced Damage

【Objective】To observe the effect of Modified Sini Powder(MSP)on the expression of hippocampal neuronal nitric oxide synthase(nNOS)in rats with chronic psychological stress.【Methods】Twenty-four Wistar rats were randomized into 3 groups: normal group,model group(receiving random stress stimulation for 21 days),and MSP group(receiving gastric infusion of MSP 3.38 g for each rat one hour before stimulation).The normal group and the model group received the same volume of saline.The expression of hippocampal nNOS was detected with immunohistochemical method.【Results】nNOS expression was found in neuronal pyramidal cells of hippocampus CA3 area in the three groups.The expression was obvious,positive cell count and its scoring were increased in the model group as compared with the normal group(P0.01),and MSP reduced the nNOS expression as well as positive cell count and its scoring in rats with chronic stress(P0.01).【Conclusion】MSP can relieve the damage induced by chronic stress in rats,and its mechanism is probably related with the high-expression of nNOS in hippocampus,thus avoid the increase of NO damaging neuronal cells.