Fig. 3. Effect of various heavy metals on the p38-MAPK phosphorylation in M. galloprovincialis gill tissue. (A) Phospho-p38-MAPK was detected in extracts (100 µg of protein) from control animals (C) or animals treated with either 1 µmol l^–1 CuCl₂ (top panel), 50 µmol l^–1 ZnCl₂ (middle panel) or 1 µmol l^–1 CdCl₂ (bottom panel) for the times indicated. Western blots shown are representative of four to six independent experiments. The molecular mass markers (kDa) are shown to the right of the panel. (B) Densitometric analysis of phospho-p38-MAPK bands by laser scanning. Results are means ± S.E.M. for four to six independent experiments performed with similar findings. P<0.001, **P<0.01 versus control value.