A–D, time courses of the whole-cell currents recorded at −80 mV from oocytes expressing T1 alone (A), T1+SUR1 (B), T1+SUR2A (C) and T1+SUR2B (D). At the start of the recordings, the oocytes were superfused with the 96K bath solution. Sodium azide, diazoxide, pinacidil, glibenclamide and barium chloride were then sequentially introduced into the bath solution as indicated by the colored bars. Iba (basal current), Iaz (azide-activated current), Idzx (diazoxide-activated current), Ipin (pinacidil-activated current) and Itot (total current) are defined in the figures. E, bar-chart plots of the basal, activated and total currents obtained from oocytes expressing T1, T1+SUR1, T1+SUR2A and T1+SUR2B. The activated currents include azide- and diazoxide-activated currents. For T1+SUR2A, pinacidil-activated currents were also measured and presented. The total current is the sum of the basal and all the activated currents (i.e. Itot= Iba + Iaz + Idzx + Ipin; for channels that are not activated by pinacidil, Itot= Iba + Iaz + Idzx).