Fig. 4.
Effect of SST on NHE8 activity in Caco-2 cells. A: charcterization of functional NHEs in Caco-2 cells. Cells were loaded with 40 mM NH4Cl for 5 min and then washed with sodium-free HBSS for 2 min before addition of sodium-containing HBSS. The rate of pHi recovery was analyzed during the initial 60 s following addition of sodium-containing HBSS in the presence or absence of NHE inhibitors HOE694 (0, 1, and 50 μM) or S3226 (80 μM). HOE694 or S3226 was included both during the NH4Cl washout phase and the recovery phase. Data were collected from 7 to 10 cells for each group. *P < 0.01 for 1 μM HOE694 vs. others; **P ≤ 0.001 for 50 μM HOE694 and 80 μM S3226 vs. others. B: effect of SST on NHE8 activity. Cells treated with or without SST (1 μM, 30 min) were loaded with 40 mM NH4Cl in HBSS for 5 min and then washed with sodium-free HBSS for 2 min before addition of sodium-containing HBSS. The rate of pHi recovery was analyzed during the initial 60 s following addition of sodium-containing HBSS in the presence of 1 μM HOE694. Data were collected from 7 to 10 cells for each group. *P < 0.01 for SST treatment vs. CT.