Fig. 4. Effect of isoflurane on the KATPchannel activated by low adenosine triphosphate (ATP). (Top ) Single-channel current traces monitored in the inside-out, excised patch mode at a membrane potential of 0 mV in external 5 mm K and internal 140 mm K. Control condition was obtained in 0.2 mm ATP. Isoflurane (0.5 mm) was added to the internal (bath) solution. The arrows indicate zero current level. (Bottom ) Summarized data from 7 patches. Control ATP concentrations were 0.2–0.5 mm.