FIGURE 4.

Altered Cl⁻ uptake in Ae4^−/− and Ae2^−/− mouse acinar cells. Cl⁻ uptake experiments were performed as described in the legend to Fig. 3 in HCO₃⁻-containing solutions (B+). Cl⁻ reuptake is shown as normalized data. A, shifting to a high Cl⁻ bath solution elicited Cl⁻ uptake in Cl⁻-depleted acinar cells of control mice (open symbols). Cl⁻ uptake was slower in Ae4^−/− and Ae2^−/− (light gray and dark gray symbols, respectively). B, summary of the initial rates of Cl⁻ uptake for experiments like those shown in A. Initial rates were calculated as in Fig. 3. Data from Ae4 WT and Ae2 control mice are shown as a single bar because they were not statistically different (Ae4 WT, n = 7; Ae4^−/−, n = 8; Ae2 control, n = 8; Ae2^−/−, n = 10). Analysis of variance followed by Bonferroni's post hoc test was performed. a, different from control (p < 0.01); b, different from Ae4^−/− (p < 0.05). C, Cl⁻ uptake was absent in HCO₃⁻-free solutions (B−) containing 30 μm EZA when cells were shifted from a low to a high Cl⁻ bath solution in Ae4^−/− mice (gray symbols) and Ae2^−/− (open symbols). Data from experiments performed in HCO₃⁻-containing solutions (B+) are replotted from A for comparison (dashed line, Ae4^−/−; dotted line, Ae2^−/−). D, summary of the initial rates of Cl⁻ uptake (Ae4^−/− B− (gray bar), n = 5; Ae2^−/− B− (open bar), n = 3). Data from Ae4^−/− and Ae2^−/− in B+ solutions are replotted for comparison (dashed and dotted bars, respectively). **, p < 0.001, Student's t test. All results are given as means ± S.E. (error bars). Representative experiments are shown in A and C.