Figure 5.

Intracellular pH in A549 cells closely follows pH changes of extracellular solution. Time course of pH_i changes after change from extracellular PS to ILS at pH 7.4 and subsequent stepwise reduction of extracellular pH to 6.5 and 6.0 (a), and to pH 5 (b). Data are representative of n = 3 independent experiments. The effect was fully reversible upon returning to extracellular pH of 7.4. All experiments were performed at 37°C; pH_i was measured by BCECF fluorescence imaging (see Methods).