| Abnormal Baroreflex Function is Dissociated from Central Angiotensin II Receptor Expression in Chronic Heart Failure. | |
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MedLine Citation:
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PMID: 22258229 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
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ABSTRACT: Neurohumoral disturbances characterize chronic heart failure (CHF) and are reflected, in part, as impairment of baroreflex sensitivity (BRS) and sympathetic function. However the mechanisms that trigger these neurohumoral abnormalities in CHF are not clear. We hypothesized that the BRS is blunted early in CHF and that the humoral effects occur later and contribute to progressive loss of cardiovascular control in CHF. We assessed the BRS (bpm/mmHg) and recorded renal sympathetic nerve activity (RSNA) in four groups of conscious rabbits at varying time intervals; control, one week CHF, two week CHF and three week CHF. CHF was induced by ventricular pacing at 360 bpm and was assessed by echocardiography. Arterial blood pressure and heart rate were recorded by an implanted telemetric device and RSNA through an implanted electrode. A significant fall in the ejection fraction, fractional shortening and an increase in LVESD & LVEDD was observed in all CHF groups. The BRS was significantly reduced in all the CHF groups with no significant change in the basal RSNA(% of maximum) after 1 week of pacing, a small but insignificant rise in RSNA was seen at 2 weeks and a significant rise in RSNA was observed at 3 weeks. AT1 receptor protein (Western Blot) and mRNA (RT-PCR) expression in the rostral ventrolateral medulla (RVLM) exhibited a progressive increase with the duration of CHF, reaching significance after 3 weeks, the same time point in which RSNA was significantly elevated. These data are the first to examine early changes in central AT1 receptors in CHF and suggest that the fall in BRS and hemodynamic changes occur early in the development of CHF followed by sympatho-excitation and over-expression of AT1 receptors with the progression of CHF causing further impairment of cardiovascular control. |
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Authors:
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Mohammad Fahim; Lie Gao; Tarek M Mousa; Dongmei Liu; Kurtis G Cornish; Irving H Zucker |
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Publication Detail:
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Type: JOURNAL ARTICLE Date: 2012-1-17 |
Journal Detail:
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Title: Shock (Augusta, Ga.) Volume: - ISSN: 1540-0514 ISO Abbreviation: - Publication Date: 2012 Jan |
Date Detail:
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Created Date: 2012-1-19 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9421564 Medline TA: Shock Country: - |
Other Details:
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Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
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Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198-5850. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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