Fig. 4. Cardiac sarcolemmal K_ATP channel activity was increased during hypoxia (6.0±0.3 kPa) in cell-attached patches on isolated goldfish ventricular myocytes. In a representative experiment, duration histograms display the relative frequency of dwell times (s) between transitions from any one current level to another in a patch containing multiple K_ATP channels. While channel closed- and open-lifetime distribution was unchanged, overall activity was enhanced. Recordings were obtained within the first 10 s after application of a depolarizing holding potential (+80 mV).