Objective: To investigate the effects of Sini San on hypothalamic pituitary adrenal axis (HPA axis) and expression of brain-derived neurotrophic factor (BDNF) and tyrosine kinase B(TrKB)in hippocampus of the depression model rats. Method: Fifty male SD rats were randomly divide into five groups:control group

model group

Venlafaxine hydrochloride group(12.5 mg·kg-1)

two concentration of sinisan groups(10

5 g·kg-1). The rats accepted 21 days both chronic mild unexpected stimulation and intragastric administration

and then

drawn blood

taken hypothalamus

taken hippocampus. To detect the content changes of the rats' plasma cortisol (CORT)

adrenocorticotropic hormone (ACTH) and hypothalamic corticotropin releasing hormone (CRH)by the radioimmunoassay. Using the immunohistochemical analysis method to test the positive neurons surface density values' change of the BDNF and TrKB in the hippocampus. Result: Compared with the control group

the rats in model group significantly increased the contents of the plasma CORT

ACTH and hypothalamic CRH

and decreased the positive neurons surface density values of the BDNF and TrKB in the hippocampus. Compared with the model group

Sini San high and low dose group could significantly decrease the content of the depression model rats' plasma CORT

ACTH and hypothalamic CRH;and increase positive neurons surface density values of the BDNF and TrKB in the hippocampus. Conclusion: Sini San can obviously improve depressive state of the rats

which mechanism may berelated with increasing the expression of BDNF and TrKB in hippocampus by the HPA.