Effect of electroconvulsive shock on the glutamate level and the hyperphosphorylation of protein tau in depression rat models whose olfactory bulbs were removed.

Abstract

To explore the effect of the electroconvulsive shock (ECS) on the glutamate level and the hyperphosphorylation of tau protein in depressed rats. The depression rat models whose olfactory bulbs were removed were established. Using the analysis of variance of factorial design, we set up two intervention factors including electric current (three levels: 25, 50, and 75 mA) and duration (three levels: 3, 6, and 9 times), which constituted 9 combinations (n=6). Fifty-four adult depression rat models whose olfactory bulbs were removed were randomly divided into nine experimental groups (n=6 in each group). The hippocampus was removed within 12 hours after the ECS finished. The level of glutamate in the hippocampus was detected by high-performance liquid chromatography, and that of Tau protein, which includes p-PHF-1(Ser396/404), p-AT8(Ser199/202), and p-12E8(Ser262), in the hippocampus with Western blot analysis. The glutamate level and the hyperphosphorylation of tau protein in the hippocampus of depressed rats remarkably increased. The changes of the hyperphosphorylation of tau protein were correlated with the electric current and duration of ECS, and these two factors showed an synergic effect. ECS enhances the hyperphosphorylation of tau protein in the hippocampus of depressed rats by up-regulating the glutamate level.