{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,16]],"date-time":"2026-03-16T12:35:04Z","timestamp":1773664504823,"version":"3.50.1"},"reference-count":0,"publisher":"Wiley","issue":"6","license":[{"start":{"date-parts":[[2004,5,5]],"date-time":"2004-05-05T00:00:00Z","timestamp":1083715200000},"content-version":"vor","delay-in-days":1281,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Experimental Physiology"],"published-print":{"date-parts":[[2000,11]]},"abstract":"<jats:p>Altering [K+]o might have different effects on action potential duration (APD) in myocytes from different regions. Therefore, the effects of [K+]o on regional differences in action potential characteristics were investigated in sub\u2010endocardial, mid\u2010myocardial and sub\u2010epicardial myocytes isolated from the base of guinea\u2010pig left ventricular free wall using three different [K+]o (2.7, 5.4 and 8.1 mM KCl). Action potentials were recorded using the switch\u2010clamp technique at 0.5 Hz. Increasing [K+]o from 2.7 to 8.1 mM shortened the action potential duration to 90% repolarization (APD90; mean APD90 values in sub\u2010endocardial, mid\u2010myocardial and sub\u2010epicardial myocytes were, respectively, 295 +\u2010 9, 286 +\u2010 9 and 266 +\u2010 8 ms in 2.7 mM [K+]o, 270 +\u2010 7, 255 +\u2010 7 and 215 +\u2010 7 ms in 5.4 mM [K+]o, 234 +\u2010 7, 212 +\u2010 10 and 155 +\u2010 8 ms in 8.1 mM [K+]o), depolarized the resting potential, and reduced the amplitude of the action potential. The effect of increasing [K+]o on action potential characteristics was more pronounced in sub\u2010epicardial myocytes than in sub\u2010endocardial and mid\u2010myocardial myocytes. The regional differences in APD90 in 5.4 mM [K+]o were increased in 8.1 mM [K+]o and abolished in 2.7 mM [K+]o. In conclusion, changing [K+]o produces more pronounced effects on action potentials in sub\u2010epicardial myocytes than in sub\u2010endocardial myocytes, modifying the normal heterogeneity of action potentials. The differences in the response of sub\u2010epicardium and sub\u2010endocardium to [K+]o may contribute to the flattening or inversion of the T wave commonly seen in patients presenting with hypokalaemia and the upright and tall T waves observed in electrocardiograms recorded during hyperkalaemia, although the underlying ionic currents remain to be determined.<\/jats:p>","DOI":"10.1111\/j.1469-445x.2000.02048.x","type":"journal-article","created":{"date-parts":[[2004,5,5]],"date-time":"2004-05-05T10:22:47Z","timestamp":1083752567000},"page":"769-774","source":"Crossref","is-referenced-by-count":13,"title":["The Effects of [K<sup>+<\/sup>]<sub>O<\/sub> on Regional Differences in Electrical Characteristics of Ventricular Myocytes in Guinea\u2010Pig"],"prefix":"10.1113","volume":"85","author":[{"given":"Xiaoping","family":"Wan","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Simon M.","family":"Bryant","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"George","family":"Hart","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2004,5,5]]},"container-title":["Experimental Physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1111%2Fj.1469-445X.2000.02048.x","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1111%2Fj.1469-445X.2000.02048.x","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/pdf\/10.1111\/j.1469-445X.2000.02048.x","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,10,29]],"date-time":"2023-10-29T12:31:10Z","timestamp":1698582670000},"score":1,"resource":{"primary":{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/10.1111\/j.1469-445X.2000.02048.x"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2000,11]]},"references-count":0,"journal-issue":{"issue":"6","published-print":{"date-parts":[[2000,11]]}},"alternative-id":["10.1111\/j.1469-445X.2000.02048.x"],"URL":"https:\/\/doi.org\/10.1111\/j.1469-445x.2000.02048.x","archive":["Portico"],"relation":{},"ISSN":["0958-0670","1469-445X"],"issn-type":[{"value":"0958-0670","type":"print"},{"value":"1469-445X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2000,11]]}}}