[Effect of Chronic Stress on PKA and P-CREB Expression in Hippocampus of Rats and the Antagonism of Antidepressors].

OBJECTIVE:To observe the effect of chronic unpredicted sequence of mild stress on the expression of cAMP-dependent protein kinase A(PKA) and phosphorylated cAMP-responsive element binding protein (P-CREB) in hippocampus of rats and the antagonism of antidepressors (fluoxetine).METHODS:Thirty-six male Sprague Dawley rats were randomly and equally allocated to 3 groups: A normal control group, a model group, and a fluoxetine group. All rats except the control group were singly housed and exposed to an unpredicted sequence of mild stressors. The different distribution and expression of PKA and P-CREB in the hippocampus of rats in different groups were investigated with immunohistochemistry and Westernblot technique.RESULTS:The positive PKA and P-CREB cells in the hippocampus of normal controls were the pyramidal cells and the granule cells. The PKA and P-CREB protein expression levels in the hippocampus of model rats were significantly lower than those of the normal controls (P<0.05). The PKA and P-CREB protein expression levels in the hippocampus of the fluoxetine group were significantly higher than those of the model group (P<0.05).CONCLUSION:Chronic unpredicted mild stress can affect the PKA and P-CREB expression in hippocampus of rats and fluoxetine has antagonism against it.