ATP-sensitive K channels in heart muscle. Spare channels.
We show that ATP-sensitive K+ channels of excised inside-out membrane patches of rat ventricular myocytes show considerable variation in their sensitivity to ATP. In 102 different membrane patches IC50 values ranged from 9 to 580 microM ATP and Hill coefficients from 1% to 6.41% of patches showed openings of ATP-sensitive K+ channels in the presence of 1 mM ATP. These results considerably widen the range of internal ATP concentrations over which one might expect activation of the ATP-sensitive K+ current in cardiac myocytes.
Findlay
I
I
Laboratoire de Physiologie Comparée (URA CNRS 1121), Université de Paris XI, Orsay, France.
Faivre
J F
JF
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D008564:Membrane Potentials; D009130:Muscle, Smooth / Q000378:metabolism*; D015221:Potassium Channels / Q000378:metabolism*; D051381:Rats
D015221:Potassium Channels; D000255:Adenosine Triphosphate