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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
1
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pubmed:dateCreated |
1991-7-25
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pubmed:abstractText |
Solution osmolarity is known to affect Na+ transport rates across tight epithelia but this variable has been relatively ignored in studies of cultured renal epithelia. Using electrophysiological methods to study A6 epithelial monolayers, we observed a marked effect of solution tonicity on amiloride-sensitive Na+ currents (I(sc)). I(sc) for tissues bathed in symmetrical hyposmotic (170 mOsm), isosmotic (200 mOsm), and hyperosmotic (230 or 290 mOsm) NaCl Ringer's solutions averaged 25 +/- 2, 9 +/- 2, 3 +/- 0.4, and 0.6 +/- 0.5 microA/cm2, respectively. Similar results were obtained following changes in the serosal tonicity: mucosal changes did not significantly affect I(sc). The changes in I(sc) were slow and reached steady-state within 30 min. Current fluctuation analysis measurements indicated that single-channel currents and Na+ channel blocker kinetics were similar for isosmotic and hyposmotic conditions. However, the number of conducting Na+ channels was approximately threefold higher for tissues bathed in hyposmotic solutions. No channel activity was detected during hyperosmotic conditions. The results suggest that Na+ channels in A6 epithelia are highly sensitive to relatively small changes in serosal solution tonicity. Consequently, osmotic effects may partly account for the large variability in Na+ transport rates for A6 epithelia reported in the literature.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/6-chloro-3,5-diaminopyrazine-3-carbo...,
http://linkedlifedata.com/resource/pubmed/chemical/Amiloride,
http://linkedlifedata.com/resource/pubmed/chemical/Potassium,
http://linkedlifedata.com/resource/pubmed/chemical/Sodium,
http://linkedlifedata.com/resource/pubmed/chemical/Sodium Channels
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pubmed:status |
MEDLINE
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pubmed:month |
Apr
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pubmed:issn |
0022-2631
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
121
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
79-90
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pubmed:dateRevised |
2007-11-14
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pubmed:meshHeading |
pubmed-meshheading:1646891-Amiloride,
pubmed-meshheading:1646891-Animals,
pubmed-meshheading:1646891-Cell Line,
pubmed-meshheading:1646891-Electric Conductivity,
pubmed-meshheading:1646891-Epithelium,
pubmed-meshheading:1646891-Kidney,
pubmed-meshheading:1646891-Kinetics,
pubmed-meshheading:1646891-Membrane Potentials,
pubmed-meshheading:1646891-Osmolar Concentration,
pubmed-meshheading:1646891-Potassium,
pubmed-meshheading:1646891-Sodium,
pubmed-meshheading:1646891-Sodium Channels,
pubmed-meshheading:1646891-Xenopus laevis
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pubmed:year |
1991
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pubmed:articleTitle |
Na+ channel activity in cultured renal (A6) epithelium: regulation by solution osmolarity.
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pubmed:affiliation |
Department of Physiology and Biophysics, University of Texas Medical Branch, Galveston 77550.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.
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