Cytosolic proteins were prepared to determine the phosphorylation levels of MAPKs. p-ERK, p-p38, and p-JNK levels were detected by Western blotting using anti p-p38-, anti p-ERK- and anti p-JNK-specific monoclonal antibodies in the cytosol. One representative blot of each protein is shown from 3 experiments that yielded similar results. Levels were normalized to total ERK, p38, JNK and β-actin. Values are the relative optical intensity of each band normalized as a percentage of the untreated control. **P<0.01, ***P<0.001 vs. normal aged rat by ANOVA. MAPKs, mitogen-activated protein kinases; ERK, extracellular signal-regulated kinase; JNK, c-Jun N-terminal kinase; ENA, enalapril; LOS, losartan.