Activation of Cdk2-pRB-E2F1 cell cycle pathway by repeated electroconvulsive shock in the rat frontal cortex

Recent reports indicate that repeated electroconvulsive shock (ECS) induces cortical cell proliferation, suggesting the possibility that ECS may activate cell cycle progression in the rat brain cortex. Sprague-Dawley rats (150-200g) were divided into four treatment groups and then given sham treatment or ECS treatment for 1, 5, and 10 days, respectively. The activity of cyclin-dependent kinase 2 (Cdk2), phosphorylation, and total protein amount of cyclin D1, cyclin E, pocket retinoblastoma family of protein (pRB), and E2F1 were analyzed in the rat cerebral cortex. The activity of Cdk2, the protein amount of pRB, Ser795 phosphorylation of pRB, and the protein amount of E2F1 were all increased compared with the sham-treated control subjects, and these increases were enhanced with the increasing number of ECS. In contrast, the protein amounts of Cdk2, cyclin D1, and cyclin E were not changed by repeated ECS. The Cdk2-pRB-E2F1 cell cycle pathway is activated by repeated ECS in the rat frontal cortex.