The ouabain-sensitive current and the NPPB-sensitive conductance were measured in cells treated with 50 μM nystatin (apical application) in a hypotonic solution. A, ouabain-sensitive currents. TY23 almost completely abolished the ouabain-sensitive current. Another PTK inhibitor, genistein (Gen; 100 μM; bilateral application), also significantly diminished the ouabain-sensitive current. Control, n= 8; TY23, n= 8; Gen, n= 4. B, TY23 and Gen significantly diminished the NPPB-sensitive conductance. Control, n= 5; TY23, n= 5; Gen, n= 3.