| Evidence for Na+/H+ exchange and pH sensitive membrane voltage in cultured bovine corneal epithelial cells. | |
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MedLine Citation:
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PMID: 2841075 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Two methods were used to investigate cellular ion transport processes in confluent monolayers of cultured bovine corneal epithelial cells: measurements of membrane voltage (V) using conventional microelectrodes, and intracellular pH (pHi) measurements using the pH sensitive absorbance of intracellularly trapped 5 (and 6)-carboxy-4', 5'dimethyl-fluorescein. (1) V averaged -39.2 +/- 0.9 mV (mean +/- SEM, n = 71) with a range of -30 to -59 mV. Increasing extracellular potassium depolarized the cell membrane with a K+-slope of 43.3 mV/decade [K+] (for [K+] between 20 and 80 mM). Intracellular as well as extracellular acidification reversibly depolarized the cell membrane. Depolarization induced by 40 mM K+-pulses was smaller at extracellular pH (pHo) of 6.9 as compared to pHo = 7.9. These findings are compatible with a pH-sensitive K+ conductance. (2) During steady state pHi was 6.96 +/- 0.05 (mean +/- SEM, n = 7). After intracellular acidification, induced by NH4Cl-prepulse technique, pHi was regulated back towards normal steady state pHi. Application of 1 mM amiloride reversibly inhibited pHi recovery. Furthermore, pHi backregulation was inhibited by removing sodium from the extracellular solution. The effect was reversible after readdition of sodium. These findings suggest that a Na+/H+ exchange is present in corneal epithelial cells and participates in pHi backregulation after an intracellular acid load. |
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Authors:
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C Korbmacher; H Helbig; C Förster; M Wiederholt |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Current eye research Volume: 7 ISSN: 0271-3683 ISO Abbreviation: Curr. Eye Res. Publication Date: 1988 Jun |
Date Detail:
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Created Date: 1988-09-13 Completed Date: 1988-09-13 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 8104312 Medline TA: Curr Eye Res Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 619-26 Citation Subset: IM |
Affiliation:
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Institut für Klinische Physiologie, Freie Universität Berlin, FRG. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Acids
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pharmacology Animals Carrier Proteins / metabolism* Cattle Cells, Cultured Cornea / cytology, metabolism*, physiology Electrophysiology Epithelial Cells Epithelium / metabolism, physiology Homeostasis Hydrogen-Ion Concentration Sodium-Hydrogen Antiporter |
| Chemical | |
Reg. No./Substance:
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0/Acids; 0/Carrier Proteins; 0/Sodium-Hydrogen Antiporter |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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