Preconditioning modifies the activities of mitogen-activated protein kinases and c-Jun transcription factor in rat hippocampus after severe hypobaric hypoxia

Abstract

The effect of preconditioning by a moderate hypobaric hypoxia on changes in the activity of the mitogen-activated (MAP) kinases EPK, JNK 1/2, and p38 and the c-Jun transcriptional factor in rat hippocampus in response to the severe hypoxia was studied using the methods of quantitative immunocytochemistry and Western-blot analysis. Severe damaging hypoxia caused a persistent activation of the JNK cascade, including JNK 1/2 and c-Jun, and also p38 kinase in the hippocampus cells. The preconditioning efficiently inhibited the expression of phosphorylated forms of JNK, c-Jun, and p38 and activated the protein kinase ERK following the severe hypoxia, which obviously promoted the survival of hippocampal neurons. The results indicate the important role of the family of MAP kinases and the c-Jun transcription factor in the processes of neuronal death/survival of the hippocampal neurons after a severe hypobaric hypoxia, and a correcting effect of preconditioning action.