Abstract: To explore the effects of anti-stress on behavior and serum concentrations of Interleukin-6(IL-6) and cortisol in chronic-stressed rats. MethodsThirtytwo healthy Wistar rats were randomly divided into four groups: the control group, the model group, the propranolol group and the phentolamine group, eight in each group. The chronic unpredictable mild stress (CUMS) model was adopted to stimulate depression in humans. Propranolol or phentolamine pretreatment was used as an anti-stress factor. At the end of the experiment, all the rat′s openfield activities were investigated, and serum IL-6 and cortisol concentrations were determined using radioimmunoassays. ResultsOpenfield activities of the model rats had significant depressive changes, with the serum concentrations of IL-6 and cortisol both significantly elevated. Phentolamine pretreatment helped suppress the behavioral changes and cortisol upregulation in stressed rats, whereas there were no obvious effect on elevation of the serum IL-6 levels. Propranolol had no antistress effect. Conclusionα Adrenergic receptor(AR) antagonist pretreatment could protect chronicstressed rats to some extent. The upregulation of stressinduced serum IL-6 may not contribute to the activation of AR in rats.

Key words: Stress, chronic, Openfield activities, Interleukin-6, Cortisol, Propranolol, Phentolamine