Fig. 2. Effect of isoflurane on single KATPchannels at intracellular pH (pHi) 7.4. (Upper ) Current traces recorded from an inside-out patch in the presence of 50 μm intracellular ATP ([ATP]i) at patch potential of +40 mV. The patch contained five channels, as determined at 0 ATP. Dashed lines denote the closed state (C). Upward deflection indicates channel opening. Isoflurane (0.5 mm) applied in the intracellular solution reversibly inhibited channel activity and decreased open probability (Po) (Lower ) All-points amplitude histograms from the recordings above demonstrate that isoflurane did not affect the amplitude of unitary current.