Involvement of p38α in Kainate-Induced Seizure and Neuronal Cell Damage

Abstract

We investigated how p38α mitogen-activated protein kinase (p38) is related to kainate-induced epilepsy and neuronal damages, by using the mice with a single copy disruption of the p38 α gene (p38α^+/−). Mortality rate and seizure score of p38α^+/− mice administered with kainate were significantly reduced compared with the case of wild-type (WT) mice. This was clearly supported by the electroencephalography data in which kainate-induced seizure duration and frequency in the brain of p38α^+/− mice were significantly suppressed compared to those of WT mice. As a consequence of seizure, kainate induced delayed neuronal damages in parallel with astrocytic growth in the hippocampus and ectopic innervation of the mossy fibers into the stratum oriens in the CA3 region of hippocampus in WT mice, whose changes were moderate in p38α^+/− mice. Likewise, kainate-induced phosphorylation of calcium/calmodulin-dependent kinase II in the hippocampus of p38α ^+/− mice was significantly decreased compared to that of WT mice. These results suggest that p38α signaling pathway plays an important role in epileptic seizure and excitotoxicity.

Key Words: :

• p38α
• Kainate
• Hippocampus
• Seizure
• Neuronal damage