{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,8]],"date-time":"2026-05-08T21:39:04Z","timestamp":1778276344935,"version":"3.51.4"},"reference-count":0,"publisher":"Rockefeller University Press","issue":"6","content-domain":{"domain":["rupress.org"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[1987,12,1]]},"abstract":"<jats:p>The mechanism of basolateral membrane base transport was examined in the in vitro microperfused rabbit proximal convoluted tubule (PCT) in the absence and presence of ambient CO2\/HCO3- by means of the microfluorometric measurement of cell pH. The buffer capacity of the cells measured using rapid NH3 washout was 42.8 +\/- 5.6 mmol.liter-1.pH unit-1 in the absence and 84.6 +\/- 7.3 mmol.liter-1.pH unit-1 in the presence of CO2\/HCO3-. In the presence of CO2\/HCO3-, lowering peritubular pH from 7.4 to 6.8 acidified the cell by 0.30 pH units and lowering peritubular Na from 147 to 0 mM acidified the cell by 0.25 pH units. Both effects were inhibited by peritubular 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonate (SITS). In the absence of exogenous CO2\/HCO3-, lowering peritubular pH from 7.4 to 6.8 acidified the cell by 0.25 pH units and lowering peritubular Na from 147 to 0 mM decreased cell pH by 0.20 pH units. Lowering bath pH from 7.4 to 6.8 induced a proton flux of 643 +\/- 51 pmol.mm-1.min-1 in the presence of exogenous CO2\/HCO3- and 223 +\/- 27 pmol.mm-1.min-1 in its absence. Lowering bath Na from 147 to 0 mM induced proton fluxes of 596 +\/- 77 pmol.mm-1.min-1 in its absence. The cell acidification induced by lowering bath pH or bath Na in the absence of CO2\/HCO3- was inhibited by peritubular SITS or by acetazolamide, whereas peritubular amiloride had no effect. In the absence of exogenous CO2\/HCO3-, cyanide blocked the cell acidification induced by bath Na removal, but was without effect in the presence of exogenous CO2\/HCO3-. We reached the following conclusions. (a) The basolateral Na\/base n greater than 1 cotransporter in the rabbit PCT has an absolute requirement for CO2\/HCO3-. (b) In spite of this CO2 dependence, in the absence of exogenous CO2\/HCO3-, metabolically produced CO2\/HCO3- is sufficient to keep the transporter running at 30% of its control rate in the presence of ambient CO2\/HCO3-. (c) There is no apparent amiloride-sensitive Na\/H antiporter on the basolateral membrane of the rabbit PCT.<\/jats:p>","DOI":"10.1085\/jgp.90.6.833","type":"journal-article","created":{"date-parts":[[2004,5,13]],"date-time":"2004-05-13T23:16:46Z","timestamp":1084490206000},"page":"833-853","update-policy":"https:\/\/doi.org\/10.1085\/jgp.crossmarkpolicy","source":"Crossref","is-referenced-by-count":42,"title":["Basolateral membrane Na\/base cotransport is dependent on CO2\/HCO3 in the proximal convoluted tubule."],"prefix":"10.1085","volume":"90","author":[{"given":"R","family":"Krapf","sequence":"first","affiliation":[{"name":"Department of Medicine, University of California, San Francisco 94143."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"R J","family":"Alpern","sequence":"additional","affiliation":[{"name":"Department of Medicine, University of California, San Francisco 94143."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"suffix":"Jr","given":"F C","family":"Rector","sequence":"additional","affiliation":[{"name":"Department of Medicine, University of California, San Francisco 94143."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"C A","family":"Berry","sequence":"additional","affiliation":[{"name":"Department of Medicine, University of California, San Francisco 94143."}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"291","published-online":{"date-parts":[[1987,12,1]]},"container-title":["The Journal of general physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/rupress.org\/jgp\/article-pdf\/90\/6\/833\/1813551\/833.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/rupress.org\/jgp\/article-pdf\/90\/6\/833\/1813551\/833.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,7,27]],"date-time":"2023-07-27T12:24:41Z","timestamp":1690460681000},"score":1,"resource":{"primary":{"URL":"https:\/\/rupress.org\/jgp\/article\/90\/6\/833\/27594\/Basolateral-membrane-Na-base-cotransport-is"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1987,12,1]]},"references-count":0,"journal-issue":{"issue":"6","published-print":{"date-parts":[[1987,12,1]]}},"URL":"https:\/\/doi.org\/10.1085\/jgp.90.6.833","relation":{},"ISSN":["0022-1295","1540-7748"],"issn-type":[{"value":"0022-1295","type":"print"},{"value":"1540-7748","type":"electronic"}],"subject":[],"published":{"date-parts":[[1987,12,1]]}}}