{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,8]],"date-time":"2026-05-08T21:39:42Z","timestamp":1778276382364,"version":"3.51.4"},"reference-count":0,"publisher":"American Physiological Society","issue":"3","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["American Journal of Physiology-Cell Physiology"],"published-print":{"date-parts":[[1991,3,1]]},"abstract":"<jats:p> Rabbit corneal epithelial cells, loaded with the pH-sensitive fluorescent dye 2',7'-bis(2-carboxy-ethyl)-5(6)-carboxyfluorescein, show a profound acidification (pH 7.33 to 6.75) in HCO3(-)-free Ringer solution when exposed to the Na(+)-H+ exchange inhibitor amiloride. This indicates that the cells are under a constant acid load that is being countered by Na(+)-H+ exchange. Amiloride-induced acidification was affected neither by incubation in Cl(-)-free Ringer solution nor by hypoxia, indicating that the potential acid loaders, Cl(-)-HCO3- (or OH-) exchange or glycolytic metabolism, are not contributing to the acidification. The possibility of a H+ influx dependent on the outward K+ gradient was tested. Perfusion with a high-K+ Ringer solution (77 mM) caused Na(+)- and Cl(-)-independent alkalinizations. Membrane depolarization by gramicidin, Ba2+, Cl(-)-free Ringer solution, or ouabain all produced small (less than 0.1 pH units) acidifications, inconsistent with contribution by a membrane potential driven passive H+ influx. In Na(+)-free Ringer solution, intracellular pH (pHi) of 6.4-6.6, addition of nigericin (a 1K(+)-1H+ ionophore) produced no significant change in pHi, indicating that [K+]i\/[K+]o = [H+]i\/[H+]o. Both amiloride-induced acidifications and high-K(+)-induced alkalinizations were significantly stimulated by the presence of 1 mM ZnSO4 and unaffected by H2-DIDS (0.5 mM, an anion transport blocker) or 100 microM SCH28080 (K(+)-H(+)-ATPase blocker). In the absence of a demonstrable H+ conductance, it is concluded that amiloride-induced acidification and K(+)-induced pHi changes are via a carrier-mediated K(+)-H+ exchanger. In addition to pHi regulation, K(+)-H+ exchange may play a role in cell volume control.(ABSTRACT TRUNCATED AT 250 WORDS) <\/jats:p>","DOI":"10.1152\/ajpcell.1991.260.3.c618","type":"journal-article","created":{"date-parts":[[2017,12,24]],"date-time":"2017-12-24T12:41:32Z","timestamp":1514119292000},"page":"C618-C625","source":"Crossref","is-referenced-by-count":32,"title":["K(+)-H+ exchange, a fundamental cell acidifier in corneal epithelium"],"prefix":"10.1152","volume":"260","author":[{"given":"J. A.","family":"Bonanno","sequence":"first","affiliation":[{"name":"Morton D. Sarver Center for Cornea and Contact Lens Research, School of Optometry, University of California, Berkeley 94720."}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"24","container-title":["American Journal of Physiology-Cell Physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.physiology.org\/doi\/pdf\/10.1152\/ajpcell.1991.260.3.C618","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,6,17]],"date-time":"2024-06-17T19:46:08Z","timestamp":1718653568000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.physiology.org\/doi\/10.1152\/ajpcell.1991.260.3.C618"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1991,3,1]]},"references-count":0,"journal-issue":{"issue":"3","published-print":{"date-parts":[[1991,3,1]]}},"alternative-id":["10.1152\/ajpcell.1991.260.3.C618"],"URL":"https:\/\/doi.org\/10.1152\/ajpcell.1991.260.3.c618","relation":{},"ISSN":["0363-6143","1522-1563"],"issn-type":[{"value":"0363-6143","type":"print"},{"value":"1522-1563","type":"electronic"}],"subject":[],"published":{"date-parts":[[1991,3,1]]}}}