Fig. 4. Changes in AO fluorescence following exposure of cells to Cl^–-free medium or SITS (0.5 mmol l^–1) under steady-state conditions followed by exposure to hypertonicity then restoration of isotonic conditions, in the continuous absence of Cl^– or presence of SITS. Data are means ± s.e.m. of 34–38 cells from three independent preparations. Data were normalized as in Fig. 3. For comparison, the control (Fig. 2A) is shown as a dotted line.