Figure 4. TOK1 openings are more frequent in the presence of isoflurane. An experiment in a excised, outside-out patch with 108 mM KCl in the pipette solution and 150 mM K-aspartate in the bath solution. Single-channel activity in the presence of isoflurane increased more than twofold in the presence of isoflurane and returned to the baseline values on washout.