Palmitate Stimulates the Epithelial Sodium Channel by Elevating Intracellular Calcium, Reactive Oxygen Species, and Phosphoinositide 3-Kinase Activity

Figure 8

LY294002 abolishes palmitate-induced ENaC activity but does not affect intracellular Ca²⁺. (a) Representative ENaC single-channel current recorded from an A6 cell before and after addition of 5 μM LY294002 first and then 0.3 mM palmitate to the basolateral bath. (b) Summarized ENaC _O under each condition, as indicated (; ). (c) Representative confocal microscopy images of A6 cells, which were loaded with Fluo-3, AM (a Ca²⁺ indicator), under control conditions (before), 5 min after treatment with LY294002, and after application of palmitate to the basolateral bath. (d) Summary plots of fluorescence intensity of Fluo-3 indicating the levels of intracellular Ca²⁺. Each point was averaged from 8 samples. Data are from 6 independent experiments (; , compared with the control).

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