| Salt Sensitivity in Blacks: Evidence That the Initial Pressor Effect of NaCl Involves Inhibition of Vasodilatation by Asymmetrical Dimethylarginine. | |
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MedLine Citation:
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PMID: 21788605 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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In healthy, mostly normotensive blacks, 19 salt-sensitive (SS) and 18 salt-resistant (SR), we tested the hypothesis that, in SS subjects, dietary NaCl loading induces its initial pressor effect by inducing a normal increase of cardiac output, while failing to induce a normal pressor-offsetting vasodilatation, consequent to its inhibition by asymmetrical dimethylarginine that is abnormally increased by NaCl. In SS and SR subjects, dietary NaCl loading, 250 from 30 mmol/d, over a 7-day period, induced similar, immediate increases in external Na(+) balance (by day 2, ≈360 mmol), plasma volume (+11%), and cardiac output (+8%). In SR subjects, from day 1, transient decreases occurred in both systemic vascular resistance (nadir: -13%, day 2) and mean arterial pressure (nadir: -5%, day 2). In SS subjects, systemic vascular resistance did not change over days 1 to 3, whereas mean arterial pressure increased progressively after day 1, ultimately by 10 mm Hg. Failure of systemic vascular resistance to normally decrease, while cardiac output normally increased, accounted for salt's initial pressor effect in the SS subjects. In SS subjects, baseline plasma levels of asymmetrical dimethylarginine (0.76μ mol/L) and symmetrical dimethylarginine (0.60 μmol/L), which does not affect vasodilatation, approximated those in SR subjects. In SS but not SR subjects, NaCl loading induced increases in asymmetrical dimethylarginine on both days 2 (+38%, median) and 7 (+14%, median). Symmetrical dimethylarginine changed in neither group. For all of the subjects combined, changes in asymmetrical dimethylarginine on day 2 predicted changes in systemic vascular resistance (R=0.751; P<0.001) and mean arterial pressure (R=0.527; P=0.006) on day 2 and similarly on day 7. These observations support the hypothesis tested. |
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Authors:
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Olga Schmidlin; Alex Forman; Anna Leone; Anthony Sebastian; R Curtis Morris |
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Publication Detail:
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Type: JOURNAL ARTICLE Date: 2011-7-25 |
Journal Detail:
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Title: Hypertension Volume: - ISSN: 1524-4563 ISO Abbreviation: - Publication Date: 2011 Jul |
Date Detail:
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Created Date: 2011-7-26 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 7906255 Medline TA: Hypertension Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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University of California, San Francisco, Department of Medicine, Division of Nephrology, San Francisco, CA; OXONON BioAnalysis, Emeryville, CA. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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