Fig. 5. Effects of 10 µmol l^-1 dopamine (DA) on transepithelial potential differences (V_te), of posterior gills of Chasmagnathus granulatus previously perfused with the phosphodiesterase inhibitor theophylline (T), as a percentage of control values (30 saline perfusate). Gills were perfused with 30 saline solution plus 2.5 mmol l^-1 T, then 10 µmol l^-1 DA was added. After stabilization, DA was withdrawn. Finally DA was applied alone (^*P<0.05; N=6).