Am J Physiol Cell Physiol AJP: Endocrinology and Metabolism
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Am J Physiol Cell Physiol 260: C618-C625, 1991;
0363-6143/91 $5.00
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Bonanno, J. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Bonanno, J. A.

AJP - Cell Physiology, Vol 260, Issue 3 C618-C625, Copyright © 1991 by American Physiological Society

ARTICLES

K(+)-H+ exchange, a fundamental cell acidifier in corneal epithelium

J. A. Bonanno
Morton D. Sarver Center for Cornea and Contact Lens Research, School of Optometry, University of California, Berkeley 94720.

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)


This article has been cited by other articles:


Home page
 Am. J. Physiol. Renal Physiol.Home page
A. Attmane-Elakeb, H. Amlal, and M. Bichara
Ammonium carriers in medullary thick ascending limb
Am J Physiol Renal Physiol, January 1, 2001; 280(1): F1 - F9.
[Abstract] [Full Text] [PDF]

Home page
 Physiol. Rev.Home page
F. LANG, G. L. BUSCH, M. RITTER, H. VOLKL, S. WALDEGGER, E. GULBINS, and D. HAUSSINGER
Functional Significance of Cell Volume Regulatory Mechanisms
Physiol Rev, January 1, 1998; 78(1): 247 - 306.
[Abstract] [Full Text] [PDF]

Home page
 Am. J. Physiol. Cell Physiol.Home page
Q. Wu and N. A. Delamere
Influence of bafilomycin A1 on pHi responses in cultured rabbit nonpigmented ciliary epithelium
Am J Physiol Cell Physiol, November 1, 1997; 273(5): C1700 - C1706.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online