Abstract: AIM: To study the effects of Suyu capsule on behaviors and hypothalamus-pituitary-adrenal axis in depression model rats induced by bilateral olfactory bulb impairment.METHODS: 48 male SD rats were randomly divided into 6 groups including the sham group, the model group, and three Suyu capsule groups(The doses were 22.8, 11.4, 5.7 g/kg, respectively) and Clomipramine group(0.02 g/kg).The depression model was established by bilateral olfactory bulb impairment.The behaviors of rats were observed using open-field and step-down test.The levels of CRH, ACTH and CORT in plasma of rats were detected by radioimmunoassay (RIA).RESULTS: Suyu capsule could decrease the numbers of crossing and rearing of depression model rats using the Open-Field test.Suyu capsule increased the latent time and diminish the mistakes for the depression model rats in the step-down test, Suyu capsule also decreased the levels of CRH, ACTH and CORT in plasma of depression model rats.CONCLUSION: Suyu capsule could reverse the behavioral changes of depression model rats induced by bilateral olfactory bulb impairment, which may be related to Suyu capsule effectively antagonize hypothalamus-pituitary-adrenal axis hyperfunction.

Key words: Suyu capsule, depressive disorder, bilateral olfactory bulb impairment, behavior, hypothalamus-pituitary-adrenal axis