title: Decreased phosphorylation and protein expression of ERK1/2 in the brain of hypoxic preconditioned mice.
abstract: Accumulated reports have suggested that activation of protein kinase C (PKC) isoforms may involve the activation of extracellular signal-regulated kinases 1/2 (ERK1/2) in the neuronal response to hypoxic stimuli. We have previously demonstrated that the membrane translocation or activation of conventional PKC (cPKC) betaII, gamma and novel PKC (nPKC) epsilon are increased in the early phase of cerebral hypoxic preconditioning in mice. However, the role of ERK1/2 in the development of cerebral hypoxic preconditioning is unclear. In the current study, we used Western blot analysis to investigate the effects of repetitive hypoxic exposure (H0-H6, n=6 for each group) on the levels of phosphorylation and protein expression of ERK1/2 in the frontal cortex and the whole hippocampus of mice. We found that the levels of phosphorylated ERK1/2, not protein expression of ERK1/2, decreased significantly in both cortex and hippocampus of the early hypoxic preconditioned mice (H1-H4), when compared to that of the normoxic group (p<0.05). In addition, a significant decrease (p<0.05) in the ERK1/2 protein expression, not the phosphorylated form of ERK1/2, was found both in the frontal cortex and hippocampus of mice followed hypoxia with previous hypoxia (H5 and H6). These results suggest that the decreased phosphorylation and downregulation of protein expression of ERK1/2 might be involved in the development of hypoxic preconditioning.
authors.affiliation: Institute for Biomedical Science of Pain, Beijing Key Laboratory for Neural Regeneration and Repairing, Department of Neurobiology, Capital University of Medical Sciences, #10 You An Men Wai Xi Tou Tiao, Beijing 100054, China.
authors.forename: Caixia
authors.initials: C
authors.lastname: Long
authors.forename: Yanan
authors.initials: Y
authors.lastname: Gao
authors.forename: Ge
authors.initials: G
authors.lastname: Gao
authors.forename: Song
authors.initials: S
authors.lastname: Han
authors.forename: Pengyu
authors.initials: P
authors.lastname: Zu
authors.forename: Li
authors.initials: L
authors.lastname: Fang
authors.forename: Junfa
authors.initials: J
authors.lastname: Li
mesh_terms: D000818:Animals; D001921:Brain / Q000098:blood supply / Q000201:enzymology*; D005625:Frontal Lobe / Q000098:blood supply / Q000201:enzymology; D006624:Hippocampus / Q000098:blood supply / Q000201:enzymology; D002534:Hypoxia, Brain / Q000201:enzymology*; D019194:Ischemic Preconditioning; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D019950:Mitogen-Activated Protein Kinase 1 / Q000096:biosynthesis*; D048052:Mitogen-Activated Protein Kinase 3 / Q000096:biosynthesis*; D010766:Phosphorylation
chemical_list: D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3