| Transport of sodium and urea in outer medullary descending vasa recta. | |
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MedLine Citation:
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PMID: 8282790 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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We dissected and perfused outer medullary vasa recta (OMVR) from vascular bundles in the rat. Permeabilities of sodium (PNa) and urea (Pu) were simultaneously determined from the lumen-to-bath efflux of 22Na and [14C]urea. PNa and Pu were also measured by in vivo microperfusion of descending (DVR) and ascending vasa recta (AVR) at the papillary tip of Munich-Wistar rats. In some OMVR PNa was indistinguishable from zero. The mean +/- SE of PNa (x 10(-5), cm/s) in OMVR was 76 +/- 9. Pu in OMVR was always very high (x 10(-5), cm/s), 360 +/- 14. There was no correlation between OMVR PNa and Pu. Inner medullary AVR and DVR had PNa of 115 +/- 10 and 75 +/- 10, respectively, and Pu of 121 +/- 10 and 76 +/- 11, respectively. PNa and Pu in papillary vasa recta were always nearly identical and highly correlated. Transport of [14C] urea in OMVR was reversibly inhibited by addition of unlabeled urea or phloretin to the bath and lumen, providing evidence for carrier-mediated transport. These data suggest that sodium and urea might traverse the wall of inner medullary vasa recta by a paracellular pathway while urea also crosses by a transcellular route in OMVR. Electron microscopic examination of seven in vitro perfused OMVR revealed no fenestrations and exposure of these vessels to 10 microM calcium ionophore A23187 or 1 nM angiotensin II resulted in reversible contraction, suggesting that in vitro perfused OMVR are DVR only. |
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Authors:
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T L Pallone; J Work; R L Myers; R L Jamison |
Publication Detail:
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Type: In Vitro; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: The Journal of clinical investigation Volume: 93 ISSN: 0021-9738 ISO Abbreviation: J. Clin. Invest. Publication Date: 1994 Jan |
Date Detail:
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Created Date: 1994-02-17 Completed Date: 1994-02-17 Revised Date: 2009-11-18 |
Medline Journal Info:
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Nlm Unique ID: 7802877 Medline TA: J Clin Invest Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 212-22 Citation Subset: AIM; IM |
Affiliation:
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Division of Nephrology, M.S. Hershey Medical Center, Pennsylvania State University, Hershey 17033. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Angiotensin II
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pharmacology Animals Arterioles / cytology, physiology*, ultrastructure Calcimycin / pharmacology Endothelium, Vascular / ultrastructure Gap Junctions / ultrastructure Kidney Medulla / blood supply* Kinetics Membrane Potentials Microcirculation / cytology, physiology*, ultrastructure Microscopy, Electron Muscle, Smooth, Vascular / cytology, physiology*, ultrastructure Nephrons / blood supply Permeability Rats Rats, Sprague-Dawley Sodium / blood, metabolism* Urea / blood, metabolism* Vasoconstriction / drug effects |
| Grant Support | |
ID/Acronym/Agency:
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DK42495/DK/NIDDK NIH HHS |
| Chemical | |
Reg. No./Substance:
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11128-99-7/Angiotensin II; 52665-69-7/Calcimycin; 57-13-6/Urea; 7440-23-5/Sodium |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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