{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,21]],"date-time":"2026-01-21T14:12:54Z","timestamp":1769004774437,"version":"3.49.0"},"reference-count":28,"publisher":"American Physiological Society","issue":"12","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Journal of Applied Physiology"],"published-print":{"date-parts":[[2013,12,15]]},"abstract":"<jats:p> Acute hypoxia is thought to trigger protective responses that, in tissues like heart and carotid body, include rapid (5\u201310 s) suppression of Ca<jats:sup>2+<\/jats:sup> and K<jats:sup>+<\/jats:sup> channels. To gain insight into the mechanism for the suppression of the cardiac l-type Ca<jats:sup>2+<\/jats:sup> channel, we measured O<jats:sub>2<\/jats:sub>-dependent fluorescence in the immediate vicinity of voltage-clamped cardiac cells subjected to rapid exchange of solutions with different O<jats:sub>2<\/jats:sub> tensions. This was accomplished with an experimental chamber with a glass bottom that was used as a light guide for excitation of a thin ruthenium-based O<jats:sub>2<\/jats:sub>-sensitive ORMOSIL coating. Fluorescence imaging showed that steady-state Po<jats:sub>2<\/jats:sub> was well controlled within the entire stream from an electromagnetically controlled solution \u201cpuffer\u201d but that changes were slower at the periphery of the stream (\u03c4<jats:sub>1\/2<\/jats:sub> \u223c 500 ms) than immediately around the voltage-clamped myocyte (\u03c4<jats:sub>1\/2<\/jats:sub> \u223c 225 ms) where, in turn, firmly attached cells produced an additional local delay of 50\u2013100 ms. Performing simultaneous voltage clamp and O<jats:sub>2<\/jats:sub> measurements, we found that acute hypoxia gradually and reversibly suppressed the Ca<jats:sup>2+<\/jats:sup> channel (Ca<jats:sub>V<\/jats:sub>1.2). Using Ba<jats:sup>2+<\/jats:sup> as charge carrier, the suppression was significant after 1.5 s, reached \u223c10% after 2.5 s, and was nearly completely reversible in 5 s. The described fluorescence measurements provide the means to check and fine tune solution puffers and suggest that changes in Po<jats:sub>2<\/jats:sub> can be accomplished within \u223c200 ms. The rapid and reversible suppression of barium current under hypoxia is consistent with the notion that the cardiac Ca<jats:sup>2+<\/jats:sup> channel is directly modulated by O<jats:sub>2<\/jats:sub>. <\/jats:p>","DOI":"10.1152\/japplphysiol.00770.2013","type":"journal-article","created":{"date-parts":[[2013,10,25]],"date-time":"2013-10-25T07:30:43Z","timestamp":1382686243000},"page":"1855-1861","source":"Crossref","is-referenced-by-count":13,"title":["A new method to detect rapid oxygen changes around cells: How quickly do calcium channels sense oxygen in cardiomyocytes?"],"prefix":"10.1152","volume":"115","author":[{"given":"John A.","family":"Scaringi","sequence":"first","affiliation":[{"name":"Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina, and Clemson University, Charleston, South Carolina"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Angelo Oscar","family":"Rosa","sequence":"additional","affiliation":[{"name":"Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina, and Clemson University, Charleston, South Carolina"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Martin","family":"Morad","sequence":"additional","affiliation":[{"name":"Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina, and Clemson University, Charleston, South Carolina"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Lars","family":"Cleemann","sequence":"additional","affiliation":[{"name":"Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina, and Clemson University, Charleston, South Carolina"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"24","reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.1124\/mol.66.2.347"},{"key":"B2","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.2013.256123"},{"key":"B3","doi-asserted-by":"publisher","DOI":"10.1093\/cvr\/cvq256"},{"key":"B4","doi-asserted-by":"publisher","DOI":"10.1002\/jcb.22956"},{"key":"B5","first-page":"796","volume":"22","author":"Chen X","year":"2002","journal-title":"Guang Pu Xue Yu Guang Pu Fen Xi"},{"key":"B6","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.1991.sp018385"},{"key":"B7","doi-asserted-by":"publisher","DOI":"10.1152\/ajpregu.90325.2008"},{"key":"B8","doi-asserted-by":"publisher","DOI":"10.1111\/j.1469-7793.1999.629ad.x"},{"key":"B9","doi-asserted-by":"publisher","DOI":"10.1161\/CIRCRESAHA.109.202267"},{"key":"B10","doi-asserted-by":"publisher","DOI":"10.1016\/j.yjmcc.2011.07.005"},{"key":"B11","unstructured":"Hille B. 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