Figure 8.

Proton gradient stability and effect of proton ionophore nigericin: (a) Cells grown on glass coverslips were loaded with BCECF-AM and placed in transport buffer at the indicated extracellular pH (pHe). Intracellular pH was assessed over the indicated time period by ratiometric fluorescence. Each point is the mean ± S.E.M. of 5 independent experiments. (b) [³H]2-chloroadenosine uptake was measured over time at pH 6.0 and pH 7.5 in the presence and absence of the proton ionophore nigericin (10 µM). Each point is the mean ± S.E.M. from 6 experiments conducted in duplicate. *Significantly different from pH 6.0 in the absence of nigericin. ^#Significantly different from pH 7.5, with or without nigericin (Two way ANOVA with Tukey’s multiple comparison test, P < 0.05).