Click on image to view larger version.

Figure 2 (A) Representative Western blot showing effect of (H₂O₂) (300 to 800 µM) on the activation and phosphorylation of the mitogen-activated protein kinases (MAPK) in neonatal rat cardiac myocytes and fibroblasts. Cells were exposed to different concentrations of H₂O₂ for a period of 30 min before protein extraction and analysis. (B–E) Densitometric evaluation of phosphoextracellular signal-regulated kinases (Erk) 1 (B), phospho Erk 2 (C), phospho p38 MAPK (D) and phospho JNK (E) activation after H₂O₂. n = 3 at each dose (two-way analysis of variance (ANOVA), p < 0.01). Results are expressed as mean ± SD. t test was used for individual comparisons. *p < 0.05, myocyte versus fibroblast. (F) Ratios of phosphorylated p38 to phosphorylated ERK 2 and phosphorylated c-jun NH₂ terminal kinase (JNK) to phosphorylated ERK 2 in cardiac myocytes and cardiac fibroblasts after treatment with H₂O₂ (300, 500, 800 µM) for 30 min. Ratios are based on means of n = 3, at each dose and after standardization of the controls to a value of 1 (two-way ANOVA, p < 0.02). M = myocyte, F = fibroblast. t test was used for individual comparisons. *p < 0.05, myocyte versus fibroblast.