| Regulation of intracellular pH in Calu-3 human airway cells. | |
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MedLine Citation:
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PMID: 11790817 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The Calu-3 human cell line exhibits features of submucosal gland serous cells and secretes HCO(3)(-). The aim of this study was to identify the HCO(3)(-) transporters present in these cells by studying their role in the regulation of intracellular pH (pH(i)). Calu-3 cells were grown on coverslips, loaded with the pH-sensitive fluorescent dye BCECF, and their fluorescence intensity monitored as an indication of pH(i). Cells were acidified with NH(4)Cl (25 mM, 1 min) and pH(i) recovery recorded. In the absence of HCO(3)(-), initial recovery was 0.208 +/- 0.016 pH units min(-1) (n = 37). This was almost abolished by removal of extracellular Na(+) and by amiloride (1 mM), consistent with the activity of a Na(+)-H(+) exchanger (NHE). In the presence of HCO(3)(-) and CO(2), recovery (0.156 +/- 0.018 pH units min(-1)) was abolished (reduced by 91.8 +/- 6.7 %, n = 7) by removal of Na(+) but only attenuated (by 63.3 +/- 5.8 %, n = 9) by amiloride. 4,4-Dinitrostilbene-2,2-disulfonic acid (DNDS) inhibited recovery by 45.8 +/- 5.0 % (n = 7). The amiloride-insensitive recovery was insensitive to changes in membrane potential, as confirmed by direct microelectrode measurements, brought about by changing extracellular [K(+)] in the presence of either valinomycin or the K(+) channel opener 1-EBIO. In addition, forskolin (10 microM), which activates the cystic fibrosis transmembrane conductance regulator Cl(-) conductance in these cells and depolarises the cell membrane, had no effect on recovery. Removal of extracellular Cl(-) trebled pH(i) recovery rates, suggesting that an electroneutral, DNDS-sensitive, Cl(-)-HCO(3)(-) exchanger together with a NHE may be involved in pH(i) regulation and HCO(3)(-) secretion in these cells. RT-PCR detected the expression of the electrogenic Na(+)-HCO(3)(-) cotransporter NBC1 and the Cl(-)-HCO(3)(-) exchanger (AE2) but not the electroneutral Na(+)-HCO(3)(-) cotransporter NBCn1. |
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Authors:
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S K Inglis; L Finlay; S J Ramminger; K Richard; M R Ward; S M Wilson; R E Olver |
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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: The Journal of physiology Volume: 538 ISSN: 0022-3751 ISO Abbreviation: J. Physiol. (Lond.) Publication Date: 2002 Jan |
Date Detail:
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Created Date: 2002-01-15 Completed Date: 2002-04-16 Revised Date: 2009-11-18 |
Medline Journal Info:
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Nlm Unique ID: 0266262 Medline TA: J Physiol Country: England |
Other Details:
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Languages: eng Pagination: 527-39 Citation Subset: IM |
Affiliation:
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Lung Membrane Transport Group, Tayside Institute of Child Health, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, UK. s.k.inglis@dundee.ac.uk |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Amiloride
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pharmacology Bicarbonates / pharmacology Buffers Carbon Dioxide / pharmacology Cell Line Cell Membrane / physiology Forskolin / pharmacology HEPES / pharmacology Homeostasis Humans Hydrogen / metabolism* Hydrogen-Ion Concentration Intracellular Membranes / metabolism* Membrane Potentials / physiology Respiratory System / cytology, drug effects, metabolism* Serous Membrane / cytology, drug effects, metabolism* Sodium / physiology Sodium-Hydrogen Antiporter / antagonists & inhibitors, physiology Solutions Stilbenes / pharmacology |
| Chemical | |
Reg. No./Substance:
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0/Bicarbonates; 0/Buffers; 0/Sodium-Hydrogen Antiporter; 0/Solutions; 0/Stilbenes; 124-38-9/Carbon Dioxide; 128-42-7/4,4'-dinitro-2,2'-stilbenedisulfonic acid; 1333-74-0/Hydrogen; 2609-46-3/Amiloride; 66428-89-5/Forskolin; 7365-45-9/HEPES; 7440-23-5/Sodium |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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