Measurements of single-channel currents in the membrane of isolated cells: ATP-dependence of K+-channels.
Single-channel currents in ventricular cells of guinea-pig hearts were recorded by the patch-clamp technique. An inwardly rectifying K+-current was found in cell-attached membrane patches. Patches could be isolated from the cell exposing the cytoplasmic face of the membrane directly to the bathing solution. After isolation, the same current as in cell-attached patches was seen if the bath contained 4 mM ATP. Without ATP, this current disappeared and another channel of larger conductance and different kinetics was activated. Currents through the latter channel were also seen in cell-attached patches after poisoning the cells by DNP. It is suggested that the ATP-dependence of the observed membrane channels mediates the increase of potassium conductance after metabolic inhibition.
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D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D004562:Electrocardiography; D006168:Guinea Pigs; D006352:Heart Ventricles / Q000166:cytology; D007473:Ion Channels / Q000502:physiology*; D009206:Myocardium / Q000166:cytology*; D011188:Potassium / Q000378:metabolism*; D012508:Sarcolemma / Q000502:physiology
D007473:Ion Channels; D000255:Adenosine Triphosphate; D011188:Potassium