| Evaluation of hepatic venous resistance responses using index of contractility. | |
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MedLine Citation:
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PMID: 1550239 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Hepatic vascular responses to 1.25 micrograms.kg-1.min-1 norepinephrine, infused into the hepatic artery, and 8-Hz nerve stimulation were monitored in anesthetized cats using a recently introduced index of contractility (IC). IC was validated in that it did not change passively in response to passive changes in portal flow or distending blood pressure, whereas the distensible venous resistance sites showed dramatic changes in resistance. Resistance is altered by both active contractile responses and passive distensibility; IC is not altered passively but is affected by changes in vascular tone. Resistance was a less sensitive index of vasoconstriction because, although the constriction increased resistance, the subsequent elevation in portal and intrahepatic pressure counteracted the constriction; the extent of active neurogenic response using resistance as the index was grossly underestimated due to venous distensibility. IC showed that pre- and postsinusoidal constriction occurred to both norepinephrine and nerves; extensive vascular escape from neurogenic constriction occurred for the portal vein so that by 5 min almost all the rise in portal pressure was due to hepatic venous constriction. |
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Authors:
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W W Lautt; D J Legare |
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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 American journal of physiology Volume: 262 ISSN: 0002-9513 ISO Abbreviation: Am. J. Physiol. Publication Date: 1992 Mar |
Date Detail:
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Created Date: 1992-04-23 Completed Date: 1992-04-23 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0370511 Medline TA: Am J Physiol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: G510-6 Citation Subset: IM |
Affiliation:
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Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Manitoba, Winnipeg, Canada. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Blood Pressure / drug effects Cats Electric Stimulation Hepatic Artery / drug effects, innervation, physiology* Mathematics Models, Cardiovascular Muscle Contraction* / drug effects Muscle, Smooth, Vascular / drug effects, innervation, physiology* Norepinephrine / pharmacology Portal Vein / drug effects, innervation, physiology* Sympathetic Nervous System / physiology* Vascular Resistance / physiology* |
| Chemical | |
Reg. No./Substance:
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51-41-2/Norepinephrine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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