FIGURE 6.
Ace stimulated calcium-independent Cl− current and ATP but not Ace increased intracellular calcium in mouse ileum and Caco-2 cells. A, effects of BAPTA-AM on (left panel) and removal of extracellular calcium (right panel) on Ace-stimulated Isc of mouse ileum. BAPTA-AM was applied serosally as indicated. AO1 was applied to ensure that current was ANO-mediated. Traces are representative of four independent experiments. B, time course for Ace + ATP induced increase in [Ca2+]i in Caco-2 cells, as detected by ratiometric Fura2 fluorescence. Stimulation with ATP activates [Ca2+]i rise. Cells were treated with 1 μm Ace followed by the addition of 100 μm ATP. Ace was not able to increase [Ca2+]i, but subsequent addition of ATP evoked a [Ca2+]i rise in these cells. Resting [Ca2+]i of these cells was around 100 nm when measured in the solution contained 10 mm glucose.