Fig. 3. Time course of the effect of excessive KCl concentration upon p38-MAPK phosphorylation in the amphibian heart. (Ai) Phospho-p38-MAPK was detected in extracts (100 µg of protein) from control hearts (C), hearts perfused with 0.5 mol l–1 sorbitol for 15 min (S), or hearts perfused with 16 mmol l–1 KCl in bicarbonate-buffered saline. (Aii) Phospho-p38-MAPK was also detected in extracts (100 µg) from hearts perfused for 30 s with excess of KCl and reperfused with normal bicarbonate-buffered saline. (Aiii) Total p38-MAPK levels were detected in identical samples as a control for loading. The western blots shown are representative of three independent experiments. Molecular mass markers (kDa) are shown to the right. (B,C) Densitometric analysis of phospho-p38-MAPK bands by laser scanning. Values are means ± S.E.M. for three independent experiments performed with similar results. Asterisks indicate values significantly different from control values; *P<0.001, **P<0.01, 
P<0.05.
