Fig. 8. The effect of pre-incubation of intestinal cells with epithelial Na⁺ channel inhibitors on (A) cell Na⁺ content or (B) cell K⁺ content in Cu-free conditions (+ 1 µmol l^–1 EDTA), with no added Cu, or after a 15 min incubation in 800 µmol l^–1 Cu_o in the presence of either 100 µmol l^–1 phenamil (black bars), 2 mmol l^–1 amiloride (light grey bars), or 10 µmol l^–1 CDPC (cross-hatched bars), compared to no added drug controls (white bars). All experiments were at normal Na⁺_o and room temperature throughout. Values are means ± S.E.M. of N=5–6 separate experiments using fresh cells from different individual fish. ^*Significant difference from control without drug within Cu_o treatment (Kruskal–Wallis test, P<0.05). Significant difference from the control with no added Cu within drug treatment (Mann–Whitney U-test, P<0.05).