Fig. 5. Changes in AO fluorescence following exposure of cells to Cl^–-free medium in the presence or absence of HCO₃^– under steady-state conditions followed by exposure to hypertonicity then restoration of isotonic conditions, in the continuous absence of Cl^– or both Cl^– and HCO₃^–. Data are means ± s.e.m. of 38–55 cells from three independent preparations. Data were normalized as in Fig. 3. For comparison, the control (Fig. 2A) is shown as a dotted line.