Effect of chronic mild stress on the expression of 5-hydroxytryptamine receptor in hippocampus of pregnant rats.

Objective To explore the effect of chronic mild stress on the expression of 5-hydroxytryptamine receptor(5-HTR)in hippocampus of pregnant rats.Methods Twenty-eight adult Wistar rats similar in age,behavior score,and body weight were randomly divided into normal control group(group A),depression group(group B),and antepartum depression group(group C).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 score and fluid consumption were determined with double-blind method,and the expression of 5-HTR in the hippocampus was detected by S-P immunohistochemical method.Results After exposed to chornic mild stress under the same conditions,the behavior score,the amount of fuild consumption,and the expression of 5-HTR were significantly lower in group C than in groups A and B(P0.05,P0.05,and P0.01,respectively),and in group B these 3 indexes were significantly lower than those in group A(P0.05,P0.05,and P0.01,respectively).The expression of 5-HTR was negatively correlated with horizontal score(r=-0.467,P=0.012)and vertical score(r=-0.478,P=0.010)and positively correlated with stopping time in center(r=0.495,P=0.007)and fluid consumption amount(r=0.667,P=0.000).No correlation was found between the expression of 5-HTR and the number of feces(P=0.901).Conclusion The pregnant rats are more sensitive to stress,and the decreased expression of 5-HTR in the hippocampus may be one of the mechanisms of antepartum depression.