Cooperative expression of survival p-ERK and p-Akt signals in rat brain neurons after transient MCAO.
In order to determine possible coordinate expression of major survival signals, immunofluorescent analyses for phosphorylated ERK (p-ERK) and phosphorylated Akt (p-Akt) were carried out after 90 min of transient middle cerebral artery occlusion (MCAO) in rats. p-Akt single positive cells (E-/A+) were found in the sham control brains with weak signal intensity. The levels of both survival signals concurrently increased from 1 to 3 h after the reperfusion with the peak at 1 h, and the signals were much stronger in the ischemic penumbra (IP) than ischemic core (IC). The number of E-/A+ cells was larger in both the IC and IP than that of p-ERK single positive cells (E+/A-). The E+/A- cells were primarily expressed at 1 h in the IP. The number of p-ERK plus p-Akt double positive cells (E+/A+) peaked at 1 h, and the intensity was much stronger in the IP than IC. These findings suggest that p-ERK and p-Akt play independent roles, respectively as emergency or maintenance signal for survival at an early stage after reperfusion, and that both signals were cooperatively expressed especially in the IP.
Li
Feng
F
Department of Neurology, Graduate School of Medicine and Dentistry, Okayama University, 2-5-1 Shikatacho, Okayama 700-8558, Japan.
Omori
Nobuhiko
N
Jin
Guang
G
Wang
Shao Jun
SJ
Sato
Keiko
K
Nagano
Isao
I
Shoji
Mikio
M
Abe
Koji
K
D000818:Animals; D001921:Brain / Q000201:enzymology*; D005455:Fluorescent Antibody Technique; D002546:Ischemic Attack, Transient / Q000201:enzymology*; D008297:Male; D020768:Middle Cerebral Artery; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009474:Neurons / Q000201:enzymology*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D051381:Rats; D017208:Rats, Wistar
D011518:Proto-Oncogene Proteins; D011505:Protein-Tyrosine Kinases; C494920:Akt1 protein, rat; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D020928:Mitogen-Activated Protein Kinases