Objective To explore initially the role of extracellular signal-regulated kinase (ERK1/2) in cerebral ischemic preconditioning. Methods Healthy adult SD rats were randomly divided into 5 groups: normal control group; sham group; ischemic preconditioning or ischemia tolerance group; bee venom group; peripheral noxious tolerance group. SDS-PAGE, Western blot and Gel Doc imagine systems were applied to determine the ERK1/2 phosphorylation and protein expression in somatosensory cortex and hippocampus of rats. Results The phosphorylation level of ERK1 in somatosensory cortex increased significantly (P<0.05) after ischemic preconditioning, while no significant changes in ERK2 and that of ERK1/2 in hippocampus. No significant changes in ERK1/2 protein expression were found both in somatosensory cortex and hippocampus after ischemic preconditioning. Conclusion The increased ERK1 phosphorylation level in somatosensory cortex may be involved in cerebral ischemic preconditioning.

Objective To explore initially the role of p38 mitogen activated protein kinases(p38 MAPK) in cerebral ischemic preconditioning.Methods Healthy adult SD rats were randomly divided into 5 groups: normal control group,sham-operated group,ischemia preconditioning or ischemia tolerance group,peripheral noxious control group,peripheral noxious tolerance group.SDS-PAGE,Western blot and Gel Doc imagine systems were applied to determine the p38 MAPK phosphorylation and protein expression in somatosensory cortex and hippocampus of rat.Results No significant changes of p38 MAPK in phosphorylation level and protein expression were found both in somatosensory cortex and hippocampus after ischemia preconditioning(P>0.05,n=6).Conclusion The development of cerebral ischemia preconditioning of rat might be not involved the phosphorylation and protein expression of p38 MAPK.

Objective To explore initially the role of c-Jun N-terminal protein kinases (JNK) in cerebral ischemia preconditioning.Methods Healthy adult SD rats were randomly divided into 5 groups: control group, sham-operated group, ischemic preconditioning or ischemic tolerance group, bee venom group, peripheral noxious tolerance group. SDS-PAGE, Western blot and Gel Doc imagine systems were applied to determine the JNK phosphorylation and protein expression in somatosensory cortex and hippocampus. Results The phosphorylation level of JNK46KD but not JNK54KD in somatosensory cortex increased significantly (P<0.05) after ischemia preconditioning, while no significant changes had been observed in that of JNK46KD and JNK54KD in hippocampus. In addition, the protein expression level of JNK46KD but not JNK54KD fell on control level in somatosensory cortex after ischemic preconditioning, while no significant changes in JNK46KD and JNK54KD protein expression were found in hippocampus. Conclusion The increased JNK46KD phosphorylation and fallen JNK46KD protein expression in somatosensory cortex may be involved in the development of cerebral ischemia preconditioning.

Objective To explore initially the roles of the 3 major signaling pathways of mitogen activated protein kinases (MAPK) in cerebral ischemia preconditioning. Methods Healthy adult SD rats were randomly divided into 3 groups: normal control group; sham-operated group and ischemic preconditioning or ischemic tolerance group (n=6). SDS-PAGE, Western blot and Gel Doc imagine systems were applied to determine the phosphorylation and protein expression of ERK, JNK and p38 in somatosensory cortex of rat. Results The phosphorylation level of ERK1 and JNK46KD in somatosensory cortex increased significantly (P<0.05) after ischemia preconditioning. Conclusion The increased ERK1 and JNK46KD phosphorylation in somatosensory cortex may be involved in the development of cerebral ischemia preconditioning and can not be ruled out in which the role of p38.