Fig. 6. K_ATP-channel effectors modulate exocytosis by influencing granular pH. (A) Increases in cell capacitance (C) under control conditions (red, n=26), after addition of Mg-ADP (green, n=12), tolbutamide and Mg-ADP (blue, n=12), diazoxide (cyan, n=19) or DIDS (magenta, n=8). (B) Average rate of changes in cell capacitance (C/t) ± s.e.m. **P<0.01; ***P<0.001. (C) Changes in granular pH estimated as the relative changes (in per cent) of the initial LysoSensor-fluorescence intensity (F/F₀) after establishment of the standard whole-cell configuration, using the Ca²⁺- and ATP-containing control solution (red, n=5), after addition of ADP (green, n=5), tolbutamide and ADP (blue, n=5) and DIDS (magenta, n=5) The arrow indicates the establishment of the standard whole-cell configuration. (D) Average changes (per cent of initial) in Lysosensor fluorescence after 60 seconds recording (F/F₀). Data are mean values ± s.e.m. ***P<0.001. Statistical significances were evaluated comparing the responses in the respective groups with the responses obtained with the ATP-containing control (red). (E), as in (C), but after supplementing the control pipette solution with: CCCP (red, n=14), ADP and CCCP (green, n=9), tolbutamide, ADP and CCCP (blue, n=10), diazoxide and CCCP (cyan, n=7), DIDS and CCCP (magenta, n=5), anti-hClC-3c and CCCP (yellow, n=9) and anti-hClC-3n and CCCP (brown, n=6). The arrow indicates the establishment of the standard whole-cell configuration. (F), as in (D), but statistical significance was evaluated by comparing the responses in the respective groups with the responses obtained when CCCP was added to the control solution (red). dz, diazoxide; tb, tolbutamide. Data are mean values ± s.e.m. **P<0.01, ***P<0.001.

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