Document Detail


Effects of angiotensin II receptor blockade during exercise: comparison of losartan and saralasin.
MedLine Citation:
PMID:  8856477     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Previous studies indicate that angiotensin II (ANG II) plays a minor role in the hemodynamic responses during dynamic exercise. However, nonspecific effects associated with methods used to block its production [e.g., angiotensin-converting enzyme (ACE) inhibitors] or receptors (e.g., saralasin) may have contributed to these findings. Losartan is a nonpeptide ANG II receptor antagonist that is devoid of such nonspecific effects. We hypothesized that the contribution of ANG II to the cardiovascular response to dynamic exercise is characterized more precisely with losartan than with saralasin. On separate days, 6 miniswine performed treadmill running at 80% of their maximal heart rate (HR) reserve (HRR) in the presence of vehicle (0.9% saline), saralasin (10 or 20 micrograms/kg/min intraleft arterially, i.a.), or losartan (15 or 20 mg/kg i.a.). Cardiac output (CO), HR, and myocardial contractility were similar among all exercise conditions. As compared with the vehicle, losartan decreased mean arterial pressure (MAP) and systemic vascular resistance (SVR) during exercise, whereas no differences occurred between the vehicle and saralasin conditions. Both receptor antagonists increased blood flow and/or decreased vascular resistance during exercise in the myocardium, stomach, small intestine, and colon. As compared with that during treadmill running with vehicle infusion, renal blood flow (RBF) was increased by losartan and decreased by saralasin. We conclude that the contribution of ANG II to the cardiovascular response to dynamic exercise is demonstrated more clearly with losartan than with saralasin.
Authors:
J D Symons; C L Stebbins
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of cardiovascular pharmacology     Volume:  28     ISSN:  0160-2446     ISO Abbreviation:  J. Cardiovasc. Pharmacol.     Publication Date:  1996 Aug 
Date Detail:
Created Date:  1997-03-25     Completed Date:  1997-03-25     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  7902492     Medline TA:  J Cardiovasc Pharmacol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  223-31     Citation Subset:  IM    
Affiliation:
Department of Internal Medicine and Human Physiology, University of California, Davis 95616, USA.
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MeSH Terms
Descriptor/Qualifier:
Angiotensin II / metabolism*
Angiotensin-Converting Enzyme Inhibitors / pharmacology*
Animals
Biphenyl Compounds / pharmacology*
Blood Pressure / drug effects,  physiology
Coronary Circulation / drug effects,  physiology
Heart Rate / drug effects,  physiology
Hemodynamics / drug effects*,  physiology*
Imidazoles / pharmacology*
Losartan
Physical Exertion / physiology*
Receptors, Angiotensin / antagonists & inhibitors*,  physiology
Regional Blood Flow / drug effects,  physiology
Renal Circulation / drug effects,  physiology
Saralasin / pharmacology*
Splanchnic Circulation / drug effects,  physiology
Swine
Swine, Miniature
Tetrazoles / pharmacology*
Water-Electrolyte Balance / drug effects,  physiology
Chemical
Reg. No./Substance:
0/Angiotensin-Converting Enzyme Inhibitors; 0/Biphenyl Compounds; 0/Imidazoles; 0/Receptors, Angiotensin; 0/Tetrazoles; 11128-99-7/Angiotensin II; 114798-26-4/Losartan; 34273-10-4/Saralasin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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