Fig. 2. Transepithelial potential differences (V_te) of posterior gills of Chasmagnathus granulatus. Gills were initially perfused with 30 saline and then perfused with 20 saline (hypo-osmotic shock), means were calculated 30 and 90-100 min after the beginning of the experiment. Then, 50 µmol l^-1 dopamine (DA) was added to the perfusion saline and reversibly reduced the stimulatory effect of hypo-osmotic perfusion. In these cases means were calculated 150-160 and 210-230 min after the beginning of the experiment. Significant differences are noted by different letters (a and b) (P<0.05; N=7).