Effect Of Chronic Mild Stress On Expression Of 5-Hydroxytryptamine And Receptor In Hippocampus Of Pregnant Rats

ObjectiveTo explore the effects of chronic mild stress on expression of 5-hydroxytryptamine and receptors in hippocampus of pregnant rats.MethodsFourty-nine adult female Wistar rats and seven male Wistar rats similar in age, behavior score and body weight were mating,after using vaginal smears and finding sperm for the first day of pregnancy. we obtain fourteen pregnant rats, as the antepartum depression group (Group C),the eighteen rats from remaining rats were randomly divided into two groups:normal group 8 rats(Group A), depression group 10 rats (Group B). The rats of Groups B and C were exposed to chronic mild stress for 18 days, followed by behavior scoring and fluid consumption test. The changes in behavior scoring and fluid consumption test were determined with Double-blind method, and the expression of 5-HT and receptor in the hippocampus was detected by Elisa and immunohistochemical method.ResultsAfter exposed to chornic mild stress under the same condtions, there were 2 rats abortion and 1 rat pseudopregnancy in Group C, the behavior score,the amount of fuild consumption,and the expression of 5-HT and receptors were significantly lower in Group C than in Group A and Group B (P<0.05, P<0.05,and P<0.01,respectively), and in Group B these 3 indexes were significantly lower than those in Group A(P<0.05, P<0.05,and P<0.01,respectively). The expression level of 5-HT and receptors was negatively correlated with horizontal score and vertical score; positively correlated with stopping time in center and fluid consumption amount. No correlation between expression level of 5-HT and receptors and number of feces was found.Conclusions1. After exposed to chornic mild stress under the same condtions, the behavior test score and fuild consumption amount of pregnant rats are significantly reduced than control group, and their expressions of 5-HT and receptor are significantly decreased.2. Both the behavior test score and fuild consumption amount and the expression level of 5-HT and receptor have obvious correlation.3. We have concluded that pregnancy is sensitive to stress environment, and the decreased expression of 5-HT and receptor in hippocampal area may be one of the mechanism of antepartum depression.