Fig. 1. Activation of the whole cell sarcolemmal adenosine triphosphate–sensitive potassium channel current (IKATP) by isoflurane and pinacidil is enhanced after in vivo anesthetic preconditioning (APC). IKATPwas monitored during a 200-ms voltage step to 0 mV applied every 15 s from a holding potential of −40 mV. ( Upper panels ) Traces of IKATPrecorded at baseline and at steady state of activation by 0.5 mm isoflurane ( A ) and 5 μm pinacidil ( B ). The magnitude of IKATPwas greater in APC than in control, non-APC myocytes. ( Lower panels in A and B ) Summary data for density (mean ± SD) of IKATPelicited by isoflurane and pinacidil (* P < 0.05, n = 10–12/group). ( C ) Representative Western blots show no difference in expression of channel subunits Kir6.2 and SUR2A in the membrane fraction from APC and non-APC rat hearts.