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. 2009 May 20;297(2):C278–C289. doi: 10.1152/ajpcell.00093.2009

Fig. 4.

Fig. 4.

Evaluation of CMEC NHE activity as Na-dependent, HOE-642-sensitive H+ flux. NH4 prepulse technique was used to evaluate NHE activity in CMEC monolayers grown on collagen-coated glass coverslips. A: representative NH4 prepulse experiment showing Na-dependent, HOE-642-sensitive pH recovery from NH4 (20 mM) prepulse-induced intracellular acidification. Data are averages of 30 cells in the field of view. All HEPES-buffered media contain 147 mM Na, except Na-free HEPES. NHE inhibitor HOE-642 was present at 10 μM. At the end of each experiment, cells were exposed to pH 5.5–8.5 media containing high-K+-nigericin to calibrate pH. B: dependence of CMEC H+ efflux inhibition on dose of HOE-642. CMEC were assessed for NH4 prepulse-induced H+ flux in the presence of 0–80 μM HOE-642. HOE-642 inhibited Na-dependent H+ flux, with IC50 of ∼7 μM. Values are means ± SE of 3 separate dose-response experiments.