Fig. 7. Immunohistochemical localisation of phosphorylated p38-MAPK in the ventricle of isolated amphibian heart perfused under various hyperosmotic conditions. Hearts were perfused under normal conditions (C), with 0.5 mol l^–1 sorbitol in the presence of 1 µmol l^–1 SB203580 (S+SB), or subjected to diverse forms of osmotic stress such as 0.5 mol l^–1 sorbitol for 15 min (S), 0.5 mol l^–1 sorbitol (15 min) followed by reperfusion (5 min) (S/Rep), 206 mmol l^–1 NaCl for 2 min (NaCl), 206 mmol l^–1 NaCl (2 min) followed by reperfusion (30 s) (NaCl/Rep), 16 mmol l^–1 KCl for 30 s (KCl), 16 mmol l^–1 KCl (30 s) followed by reperfusion (30 s) (KCl/Rep). After the removal of atria, ventricles were cryosectioned longitudinally and fixed with ice-cold acetone. Specimens were incubated with phospho-p38-MAPK antibody (1:200 dilution) and counterstained with Haematoxylin. The figure shows representative photographs from three independent experiments performed with similar results. Immunoreaction deposits are visualised with Fast Red chromogen. Bar, 20 µm.