Objective:To investigate the expression levels of Serotonin 3A/B receptor（5-HT3A/BR） in primarily cultured rat hippocampus neurons stimulated with serum respectively from depressive rats and different drugs treated depressive rats for exploring mechanisms of Shuyu Capsule.Method:The rats were divided randomly into five groups including normal control

model with depression

treatment groups treated with Shuyu capsule（0.51 g · kg-1）

saikosaponin（0.4 g · kg-1） and fluoxetine（0.002 g · kg-1）

respectively.The depression emotion model was set up by the methods of isolated breed and chronic mild stress for 28 days.Serum of rats in every group was collected

inactivated and sterilized.After serum contained hippocampus neurons treatment in every group respectively for 24 hours

Western blot and immunoflurescence were separately used to detect the expression levels of 5-HT3A and 5-HT3B receptor protein in neurons.Result:The expression of 5-HT3A and 5-HT3B receptor in neurons incubating with serum of rats in model group increased obviously（P<0.01

P<0.05）compared with those in the serum from normal control rat treated neurons.Comparing with the neurons treated with model rats serum

the expression of 5-HT3A receptor in neurons incubated with serum of drug treatment rats were significantly improved（P<0.01）

but the expression of 5-HT3B receptor was no statistical difference.Conclusion:The expression of 5-HT3 receptor in neurons was closely related with depression

and the differential expression of 5-HT3AR and 5-HT3BR may play important roles in depression emotion.Shuyu

saikosaponin and fluoxetine showed the same tendency on these two proteins expression of neurons

indicating that Shuyu capsule and saikosaponin have notable effect on depression therapy by improving the 5-HT3AR protein expression levels in hippocampus neurons.