Fig. 4. Inhibitor of protein kinase C chelerythrine abolishes isoflurane (ISO)–induced potentiation of sarcolemmal adenosine triphosphate–sensitive potassium channel current (I^KATP). Shown are representative time course experiments conducted in the continued presence of 5 μm chelerythrine, which was applied to the myocytes in the pipette solution. (  A ) In the presence of chelerythrine, I^KATPelicited by 5 μm pinacidil (PIN) after pretreatment with isoflurane and its washout was markedly reduced, indicating that chelerythrine abolishes isoflurane-induced potentiation of I^KATP. (  B ) Chelerythrine had no effect on pinacidil-activated current under control, anesthetic-free conditions, confirming that this protein kinase C inhibitor alone does not affect channel opening by pinacidil. GLIB = glibenclamide.