Fig. 6. Changes in AO fluorescence following exposure of cells to Na⁺-free medium or amiloride (100 µmol l^–1) under steady-state conditions followed by exposure to hypertonicity then restoration of isotonic conditions, in the continuous absence of Na⁺ or presence of amiloride. Data are means ± s.e.m. of 34–41 cells from three independent preparations. Data were normalized as in Fig. 3. For comparison, the control (Fig. 2A) is shown as a dotted line.