Fig. 5.

Benzamil increases intercalated cell intracellular pH (pH_i) independently of pendrin-mediated apical Cl⁻/HCO₃⁻ exchange. pH_i was measured in intercalated cells loaded with BCECF (see methods). The solutions employed are displayed in Table 1. Perfusate K⁺, Cl⁻, and HCO₃⁻ concentrations were the same in all experiments. In all experiments, NaCl was absent from the bath solution (solution 5). A and B: effect of benzamil applied to the perfusate on intercalated cell pH_i in CCDs from wild-type mice, with Na⁺ present (A, solution 3) or absent (B, solution 4) in the luminal fluid. C: effect of benzamil on intercalated cell pH_i in CCDs from pendrin null mice, when perfused in the presence of luminal Na⁺ (solution 3).