Aa, representative single-channel recording of the SUR2B/Kir6.2 channel illustrating the effects of pinacidil (Pin) and glibenclamide (Gli) in the cell-attached and excised (arrow and IO) inside-out membrane patch. Ab, apparent antagonism of ATP-evoked inhibition of SUR2B/Kir6.2 channels induced by pinacidil. Each symbol shows the ATP-induced channel inhibition in the absence (○) or presence of pinacidil (□, at 100 μm; and ▵, 300 μm). The continuous lines were fitted with eqn (1). B, representative single-channel recordings of SUR2B/Kir6.1 channels illustrating the effects of ATP (a), AMP (b) and ADP (b) in the absence or presence of pinacidil. At the points indicated by IO, the patches were excised from their cells. In each membrane current recording the zero current level is indicated by a thin horizontal line.