Abstract: AIM: To study the effects of paroxetine on the level of cortisol and behavior of rats with psychological stress.METHODS: The rat psychological stress model was made by restraint stress. Expression of c-fos positive cells was detected by SP immunohistochemical assay in the rat PVN. The cortisol was analysed by radioimmnoassay and the behaviors of rats were tested in open-field conditions.RESULTS: The expression of c-fos positive cells, the crossing scores ,the rearing scores and the level of cortisol increased more significantly in the other groups than those in the control group , but decreased in the paroxetine group(P<0.05). The paroxetine inhibited the expression of c-fos positive cells in the PVN and the behaviors,reduced the level of cortisol of rats after psychological stress.CONCLUSION: The effects of paroxetine on the anxiety disorders in rats may be related to inhibit the expression of c-fos positive downregulation of the activation of HPA pathway.

Key words: Paroxitine, Stress, Behavior, C-fos, Cortisol hypothalamus