Fig. 1. Time course of p38-MAPK phosphorylation in the amphibian heart, in response to reperfusion after sorbitol treatment. (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 reperfused for the indicated times with normal bicarbonate-buffered saline following a 15 min perfusion with 0.5 mol l^–1 sorbitol. Molecular mass markers (kDa) are shown to the right. (Aii) Identical samples immunoblotted for total p38-MAPK levels, as a control for loading. (B) Densitometric analysis of phospho-p38-MAPK bands by laser scanning. Results are means ± S.E.M. for three independent experiments performed with similar findings. Re, reperfusion. The western blots are representative of three independent experiments. *Significantly different from control value (P<0.001).