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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: The Cdk2-pRB-E2F1 cell cycle pathway is activated by repeated ECS in the rat frontal cortex.