{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,13]],"date-time":"2026-02-13T14:00:31Z","timestamp":1770991231099,"version":"3.50.1"},"reference-count":29,"publisher":"Wiley","issue":"2","license":[{"start":{"date-parts":[[2005,2,4]],"date-time":"2005-02-04T00:00:00Z","timestamp":1107475200000},"content-version":"vor","delay-in-days":5939,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Journal Cellular Physiology"],"published-print":{"date-parts":[[1988,11]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>The regulation of intracellular pH (pH<jats:sub>i<\/jats:sub>) was monitored in a virus\u2010transformed cell clone derived from bovine ciliary body exhibiting characteristics of pigmented ciliary epithelium. Data were obtained from confluent monolayers grown on plastic coverslips in nominally bicarbonate\u2010free media using the pH\u2010sensitive absorbance of 5\u2010 (and 6\u2010) carboxy\u20104\u2032,5\u2032\u2010dimethylfluorescein. Under resting conditions, pH<jats:sub>i<\/jats:sub> averaged 6.98 \u00b1 0.01 (SEM; n = 57). When cells were acid loaded by briefly exposing them to Ringer containing NH<jats:sub>4<\/jats:sub><jats:sup>+<\/jats:sup> and the withdrawing the NH<jats:sub>4<\/jats:sub><jats:sup>+<\/jats:sup>, pH<jats:sub>i<\/jats:sub> spontaneously regained its initial value. In the presence of 1 mM amiloride or in the absence of Na<jats:sup>+<\/jats:sup>, this process was blocked, indicating the involvement of an Na<jats:sup>+<\/jats:sup>\/H<jats:sup>+<\/jats:sup> exchanger in the regulation of pH<jats:sub>i<\/jats:sub> after an acid load. Removing Na<jats:sup>+<\/jats:sup> during resting conditions decreased cytoplasmatic pH. This acidification could be slowed by amiloride, which is evidence for reversal of the Na<jats:sup>+<\/jats:sup>\/H<jats:sup>+<\/jats:sup> countertransport exchanging intracellular Na<jats:sup>+<\/jats:sup> for extracellular protons. Application of 1 mM amiloride during steady state led to a slow acidification. Thus the Na<jats:sup>+<\/jats:sup>\/H<jats:sup>+<\/jats:sup> exchanger is operative during resting conditions extruding protons, derived from cellular metabolism, or from downhill leakage into the cell. Addition of Na<jats:sup>+<\/jats:sup> to Na<jats:sup>+<\/jats:sup> \u2010depleted cells led to an alkalinization, which was senstive to amiloride, with an IC<jats:sub>50<\/jats:sub> of about 20 \u03bcM. This alkalinization was attributed to the Na<jats:sup>+<\/jats:sup>\/H<jats:sup>+<\/jats:sup> exchanger and exhibited saturation kinetics with increasing Na<jats:sup>+<\/jats:sup> concentrations, with an apparent K<jats:sub>M<\/jats:sub> of 29.6 mM Na<jats:sup>+<\/jats:sup>. It is concluded that Na<jats:sup>+<\/jats:sup>\/H<jats:sup>+<\/jats:sup> exchange regulates pH<jats:sub>i<\/jats:sub> during steady state and after an acid load.<\/jats:p>","DOI":"10.1002\/jcp.1041370225","type":"journal-article","created":{"date-parts":[[2005,2,26]],"date-time":"2005-02-26T10:57:08Z","timestamp":1109415428000},"page":"384-389","source":"Crossref","is-referenced-by-count":16,"title":["Na<sup>+<\/sup>\/H<sup>+<\/sup> exchange regulates intracellular pH in a cell clone derived from bovine pigmented ciliary epithelium"],"prefix":"10.1002","volume":"137","author":[{"given":"Horst","family":"Helbig","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Christoph","family":"Korbmacher","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Friederike","family":"Stumpff","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Miguel","family":"Coca\u2010Prados","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Michael","family":"Wiederholt","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2005,2,4]]},"reference":[{"key":"e_1_2_1_2_1","doi-asserted-by":"publisher","DOI":"10.1146\/annurev.ph.47.030185.002553"},{"key":"e_1_2_1_3_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0002-9394(14)78041-9"},{"key":"e_1_2_1_4_1","doi-asserted-by":"publisher","DOI":"10.1152\/ajpcell.1982.242.3.C131"},{"key":"e_1_2_1_5_1","doi-asserted-by":"publisher","DOI":"10.1152\/physrev.1975.55.3.383"},{"key":"e_1_2_1_6_1","doi-asserted-by":"publisher","DOI":"10.1085\/jgp.81.1.53"},{"key":"e_1_2_1_7_1","doi-asserted-by":"publisher","DOI":"10.1085\/jgp.86.6.795"},{"key":"e_1_2_1_8_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0014-4835(86)80028-8"},{"key":"e_1_2_1_9_1","doi-asserted-by":"publisher","DOI":"10.1016\/0014-4835(85)90142-3"},{"key":"e_1_2_1_10_1","doi-asserted-by":"publisher","DOI":"10.1016\/0006-291X(87)91343-X"},{"key":"e_1_2_1_11_1","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.83.22.8754"},{"key":"e_1_2_1_12_1","doi-asserted-by":"publisher","DOI":"10.1016\/0014-4835(88)90091-7"},{"key":"e_1_2_1_13_1","doi-asserted-by":"publisher","DOI":"10.1007\/BF01995698"},{"key":"e_1_2_1_14_1","doi-asserted-by":"crossref","first-page":"12120","DOI":"10.1016\/S0021-9258(18)67211-4","article-title":"The regulation of intracellular pH in monkey kidney epi thelial cells (BSC\u20101)","volume":"261","author":"Jentsch T. 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