Click on image to view larger version.

Figure 5 Effect of tumor necrosis factor-alpha (TNF) (10 ng/ml) on murine cardiomyocytes. (A) Representative Western blots of total and phosphorylated p38-MAPK from outbred C57BL/6 mouse cardiomyocytes preincubated for 30 min with increasing concentrations of TNF (0, 50, 100 ng/ml). Lower panel shows quantitative data expressed as fold increase of phosphorylation relative to control (mean ± SEM; n = 3). These cells exhibited a substantial basal p38-MAPK dual phosphorylation, and TNF, even at high doses, only induced a 3-fold increase in p38-MAPK dual phosphorylation. (B) Representative Western blots of total and phosphorylated p38-MAPK from C57BL/6 mouse cardiomyocytes and perfused hearts both exposed to TNF (10 ng/ml) for 15 min (n = 3). Cardiomyocytes exhibited considerable basal p38-MAPK dual phosphorylation which was absent in perfused hearts. Furthermore, p38-MAPK dual phosphorylation in perfused hearts was greater than in cardiomyocytes (25-fold vs. 3-fold increase, respectively).