c-Jun N-terminal kinase activation in hippocampal CA1 region was involved in ischemic injury

To clarify the role of c-Jun N-terminal kinase (NK) activation in brain ischemia, temporospatial alteration of active (diphosphorylated) JNK1/2 immunoreactivity in hippocampus after brain ischemia in rat was investigated. Western immunoblot study showed that JNK1/2 diphosphorylation level was increased biphasically in CA1 but not CA3/dentate gyrus (DG) after 10 min of ischemia. Cerebral ventricular infusion of JNK1/2 antisense oligonucleotides not only significantly decreased JNK1/2 protein expression and the activation level but also significantly decreased CA1 pyramidal cell death (demonstrated by cresyl violet staining) and DNA fragmentation (demonstrated by in situ end-labeling of DNA). These results suggest that JNK1/2 were selectively activated and involved in the selective cell death in hippocampal CA1 subfield after cerebral ischemia.