Figure 3.

Characterization of the effects of pharmacological compounds on the activity of the Na⁺/H⁺ exchanger using the double-pulse assay. Na⁺/H⁺ exchanger activity was determined as described in Figure 2 and in the Section 4, using a dual ammonium chloride pulse assay. The rate of recovery in the first pulse, in the absence of the drug, was measured. This was compared to the rate of recovery in the second pulse, in the presence of the drug. When both pulses were in the absence of the drugs, the two recoveries were equivalent. (A) A double-pulse assay; the second pulse was treated with vehicle only (no drug). (B) A double-pulse assay wherein the second pulse was in the presence of 10 µM BB2-50F. (C–G) A summary of the results of the double-pulse Na⁺/H⁺ exchanger assays (black line) for the compounds AA1-135, AA1-111, BB2-30F, BB2-50F, and EMD87580, respectively (IC₅₀ values in Table 1). Additionally, the same figures (C–G) show the effects of these compounds on uPA activity (red line), assayed as describe d in the Section 4.