{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,23]],"date-time":"2026-06-23T04:20:48Z","timestamp":1782188448131,"version":"3.54.5"},"reference-count":0,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[1984,2,1]],"date-time":"1984-02-01T00:00:00Z","timestamp":444441600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["The Journal of Physiology"],"published-print":{"date-parts":[[1984,2]]},"abstract":"<jats:p>Single ventricular cells were enzymatically isolated from adult guinea\u2010pig hearts (Isenberg &amp; Kl\u00f6ckner, 1982). The patch\u2010clamp technique (Hamill, Marty, Neher, Sakmann &amp; Sigworth, 1981) was used to examine the conductance properties of an inward\u2010rectifying K+ channel present in their sarcolemmal membrane. When the K+ concentration on the extracellular side of the patch was between 10.8 and 300 mM, inward current steps were observed at potentials more negative than the K+ equilibrium potential (EK). At more positive potentials no current steps were detectable, demonstrating the strong rectification of the channel. The zero\u2010current potential extrapolated from the voltage dependence of the inward currents depends on the external K4 concentration [K+]o in a fashion expected for a predominantly K+\u2010selective ion channel. It is shifted by 49 mV for a tenfold change in [K+]o. The conductance of the channel depends on the square root of [K+]o. In approximately symmetrical transmembrane K+ concentrations (145 mM\u2010external K+), the single\u2010channel conductance is 27 pS (at 19\u201023 degrees C). In normal Tyrode solution (5.4 mM\u2010external K+) we calculate a single\u2010channel conductance of 3.6 pS. The size of inward current steps at a fixed negative membrane potential V increases with [K+]o. The relation between step size and [K+]o shows saturation. Assuming a Michaelis\u2010Menten scheme for binding of permeating K+ to the channel, an apparent binding constant of 210 mM is calculated for a membrane potential of \u2010100 mV. For this potential the current at saturating [K+]o is estimated as 6.5 pA. The rectification of the single\u2010channel conductance at membrane potentials positive to EK occurs within 1.5 ms of stepping the membrane potential from a potential of high conductance to one of low conductance. In addition to the main conductance state, the channel can adopt several substates of conductance. The main state could be the result of the simultaneous opening of four conducting subunits, each of which has a conductance of about 7 pS in 145 mM\u2010external K+. The density of the inward\u2010rectifying K+ channels in the ventricular sarcolemma is 0\u201010 channel\/10 micron2 of surface membrane; the average of twenty\u2010eight patches was 1 channel\/1.8 micron2. It is concluded that the inward\u2010rectifying K+ channels mediate the resting K+ conductance of ventricular heart muscle and the current termed IK1 in conventional voltage\u2010clamp experiments.<\/jats:p>","DOI":"10.1113\/jphysiol.1984.sp015088","type":"journal-article","created":{"date-parts":[[2014,12,19]],"date-time":"2014-12-19T06:51:20Z","timestamp":1418971880000},"page":"641-657","source":"Crossref","is-referenced-by-count":332,"title":["Conductance properties of single inwardly rectifying potassium channels in ventricular cells from guinea\u2010pig heart."],"prefix":"10.1113","volume":"347","author":[{"given":"B","family":"Sakmann","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"G","family":"Trube","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[1984,2]]},"container-title":["The Journal of Physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1113%2Fjphysiol.1984.sp015088","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/pdf\/10.1113\/jphysiol.1984.sp015088","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,10,19]],"date-time":"2023-10-19T20:24:52Z","timestamp":1697747092000},"score":1,"resource":{"primary":{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/10.1113\/jphysiol.1984.sp015088"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1984,2]]},"references-count":0,"journal-issue":{"issue":"1","published-print":{"date-parts":[[1984,2]]}},"alternative-id":["10.1113\/jphysiol.1984.sp015088"],"URL":"https:\/\/doi.org\/10.1113\/jphysiol.1984.sp015088","archive":["Portico"],"relation":{},"ISSN":["0022-3751","1469-7793"],"issn-type":[{"value":"0022-3751","type":"print"},{"value":"1469-7793","type":"electronic"}],"subject":[],"published":{"date-parts":[[1984,2]]}}}