ATP-dependent potassium channels in the cardiac cell.
Patch-clamp techniques were used to study the ATP-dependent K+ channel in single ventricular myocytes from guinea pig hearts. During long lasting whole-cell recordings an increase of a time-independent K+ outward current could be observed. This outward current could be inhibited by the intracellular application of ATP (3-20 mM), but not by the Ca2+-chelator EGTA (20 mM). The blocking effect of ATP was also observed in single-channel experiments. The hypoglycaemic sulphonylurea tolbutamide specifically inhibited the ATP-dependent K+ current in whole-cell recordings, inside-out and outside-out patches (IC50 = 0.4 mM).
D000200:Action Potentials / Q000187:drug effects; D000255:Adenosine Triphosphate / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism*; D014044:Tolbutamide / Q000494:pharmacology
D007473:Ion Channels; D000255:Adenosine Triphosphate; D014044:Tolbutamide; D011188:Potassium