Fig. 3. Transepithelial Na⁺ and Cl^- flux measurements before and after apical treatment with 10 µmol l^-1 amiloride. (A) Unidirectional, apical-to-basolateral (apical-blm), basolateral-to-apical (blm-apical) and net ((apical-blm)-(blm-apical)) Na⁺ fluxes across epithelial tissues bathed in symmetric avian saline solution and voltage clamped at 0 mV (N=6). (B) Unidirectional and net Cl^- fluxes across under the same conditions stated in A (N=5). (C) Effects of apical amiloride (10 µmol l^-1) on I_sc and conductance (G) measurements obtained from tissues used in the transepithelial flux experiments. ^*Significantly different from control value (P<0.05).