Fig. 1. Summary data for adenosine triphosphate (ATP) sensitivity of single K^ATPchannels at intracellular pH (pHi) 7.4. Symbols and error bars are means ± SEM. Each data point is a mean from four inside-out patches. Normalized mean open probability (Po) data obtained in control (open symbols) and in the presence of 0.5 mm isoflurane (closed symbols) are plotted against intracellular ATP ([ATP]i) concentrations. Solid line is a Hill fit (see Methods) to mean control data. The IC⁵⁰for ATP inhibition and the Hill coefficient are reported in Results. At pHi 7.4, isoflurane decreased Po independently of [ATP]i. The dotted line connects mean isoflurane data points.