Block by Cs of K current iK1 and of carbachol induced K current iCch in frog atrium.
1. In frog atrium, Cs ions block both the inward rectifier iK1 and the carbachol induced K current iCch. 2. Both iK1 and iCch display a high affinity for Cs with a K0.5 of 4 X 10(-5) M for iK1 and of 8 X 10(-5) M for iCch at V = -50 mV. 3. Block of both iK1 and iCch is strongly voltage dependent. When fitted by the block model of Woodhull (1973), delta is greater than 1 for the two currents. 4. From these similarities, action of Cch on frog atrium K permeability could be interpreted as a modification of iK1.
D000818:Animals; D002217:Carbachol / Q000494:pharmacology*; D002586:Cesium / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006321:Heart / Q000502:physiology*; D006325:Heart Atria; D007473:Ion Channels / Q000187:drug effects*; D007552:Isotonic Solutions / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism*; D011893:Rana esculenta; D000077331:Ringer's Solution
D007473:Ion Channels; D007552:Isotonic Solutions; D002586:Cesium; D000077331:Ringer's Solution; D002217:Carbachol; D011188:Potassium