{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,5,20]],"date-time":"2025-05-20T13:32:19Z","timestamp":1747747939440},"reference-count":0,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"5","content-domain":{"domain":["www.ahajournals.org"],"crossmark-restriction":true},"short-container-title":["Circulation Research"],"published-print":{"date-parts":[[1981,11]]},"abstract":"<jats:p>The relationship between membrane potential (Em) and the potassium equilibrium potential (EK) was investigated in hypoxic guinea pig papillary muscle. After more than 8 hours of hypoxia, cells with near normal Em (-86.2 +\/- 0.9 mV) and action potentials were observed. However, the intracellular potassium concentration ([K+]i) based on chemical analysis and the assumption that potassium was homogeneously distributed was 41.8 +\/- 4.3 mM; the apparent EK was -55.7 +\/- 2.9 mV, significantly positive to Em. Measurements with potassium ion-selective microelectrodes revealed that prolonged hypoxia results in at least two populations of cells with different characteristics. The first population had an intracellular potassium activity (aiK) of 101.5 +\/- 1.9 mM, and EK was 4.7 mV negative to Em. In contrast, EK was 33.4 +\/- 1.3 mV negative to Em in the second population. These cells also exhibited a reduced sensitivity to changes in bath potassium, and calculations suggest aiK was about 18 mM. The existence of cell populations with a near normal and very low aiK can explain the intermediate value of [K+]i calculated assuming a homogenous potassium distribution. Cells with near normal Em and action potentials represent the population with near normal aiK. Hypoxia may also cause non-uniform changes in other cellular characteristics.<\/jats:p>","DOI":"10.1161\/01.res.49.5.1181","type":"journal-article","created":{"date-parts":[[2012,6,12]],"date-time":"2012-06-12T00:17:09Z","timestamp":1339460229000},"page":"1181-1189","update-policy":"http:\/\/dx.doi.org\/10.1161\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":18,"title":["Heterogeneity of intracellular potassium activity and membrane potential in hypoxic guinea pig ventricle."],"prefix":"10.1161","volume":"49","author":[{"given":"C M","family":"Baumgarten","sequence":"first","affiliation":[]},{"given":"C J","family":"Cohen","sequence":"additional","affiliation":[]},{"given":"T F","family":"McDonald","sequence":"additional","affiliation":[]}],"member":"276","container-title":["Circulation Research"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.ahajournals.org\/doi\/pdf\/10.1161\/01.RES.49.5.1181","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,5,12]],"date-time":"2024-05-12T19:17:58Z","timestamp":1715541478000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.ahajournals.org\/doi\/10.1161\/01.RES.49.5.1181"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1981,11]]},"references-count":0,"journal-issue":{"issue":"5","published-print":{"date-parts":[[1981,11]]}},"alternative-id":["10.1161\/01.RES.49.5.1181"],"URL":"https:\/\/doi.org\/10.1161\/01.res.49.5.1181","relation":{},"ISSN":["0009-7330","1524-4571"],"issn-type":[{"value":"0009-7330","type":"print"},{"value":"1524-4571","type":"electronic"}],"subject":[],"published":{"date-parts":[[1981,11]]},"assertion":[{"value":"1981-11-01","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}