| Exercise training enhances baroreflex control of heart rate by a vagal mechanism in rabbits with heart failure. | |
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MedLine Citation:
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PMID: 12015354 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Moderate exercise training (Ex) enhances work capacity and quality of life in patients with chronic heart failure (CHF). We investigated the autonomic components of resting heart rate (HR) and the baroreflex control of HR in conscious, instrumented rabbits with pacing-induced CHF after Ex. Sham and CHF rabbits were exercise trained for 4 wk at 15-18 m/min, 6 days/wk. Arterial pressure and HR were recorded before and after metoprolol (1 mg/kg iv) or after atropine (0.2 mg/kg iv). Mean arterial pressure was altered by infusions of sodium nitroprusside and phenylephrine. The data were fit to a sigmoid (logistic) function. Baseline HRs were 266.5 +/- 8.4 and 232.1 +/- 1.6 beats/min in CHF and CHF Ex rabbits, respectively (P < 0.05). In the unblocked state, CHF rabbits had a significantly depressed peak baroreflex slope (1.7 +/- 0.3 vs. 5.6 +/- 0.7 beats. min(-1). mmHg(-1); P < 0.001) and HR range (128.6 +/- 34.5 vs. 253.2 +/- 20.3 beats/min; P < 0.05) compared with normal subjects. Ex increased baroreflex slope to 4.9 +/- 0.3 from 1.7 +/- 0.3 beats. min(-1). mmHg(-1) in unblocked rabbits (P < 0.001 compared with CHF non-Ex). Ex did not alter baroreflex function in sham animals. After metoprolol, baroreflex slope was significantly increased in CHF Ex rabbits (1.5 +/- 0.2 vs. 3.0 +/- 0.2 beats. min(-1). mmHg(-1); P < 0.05). After atropine, there was no significant change in baroreflex slope or HR range between CHF Ex and CHF rabbits. These data support the view that enhancement of baroreflex control of HR after Ex is due to an augmentation of vagal tone. |
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Authors:
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Jun-Li Liu; Jay Kulakofsky; Irving H Zucker |
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Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 92 ISSN: 8750-7587 ISO Abbreviation: J. Appl. Physiol. Publication Date: 2002 Jun |
Date Detail:
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Created Date: 2002-05-16 Completed Date: 2002-10-23 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: United States |
Other Details:
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Languages: eng Pagination: 2403-8 Citation Subset: IM |
Affiliation:
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Department of Physiology and Biophysics, University of Nebraska Medical Center, Omaha, Nebraska 68198-4575, USA. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Arteries / physiopathology Baroreflex / physiology* Blood Pressure Cardiac Output, Low / physiopathology* Coronary Vessels / physiopathology Heart Conduction System / physiopathology Heart Rate / physiology* Male Physical Conditioning, Animal / physiology* Rabbits Reference Values Sympathetic Nervous System / physiopathology Vagus Nerve / physiopathology* |
| Grant Support | |
ID/Acronym/Agency:
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P0-1 HL-62222/HL/NHLBI NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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