Fig. 3.
Properties of wild-type and mutant KATP channels in inside-out patches. (A) Current–voltage relationships obtained from inside-out patches excised from cells expressing Kir6.2/SUR1 revealed macroscopic inwardly rectifying adenosine triphosphate (ATP)-sensitive currents in symmetrical K+ concentrations. (B) Mean slope conductance (G) in the presence of ATP or tolbutamide (Tb) expressed as a fraction of the conductance in the absence of the drug (Gc). ATP inhibition was concentration dependent for Kir6.2/SUR1 and absent for Kir6.2-K185Q/SUR1 currents. Numbers (N) are given above the bars. **P < 0.01 compared with control. (C, D) Current–voltage relationships obtained for Kir6.2/SUR1 and Kir6.2-K185Q/SUR1 currents, respectively, in the absence and presence of 0.1 mm tolbutamide.