Document Detail


Effects of exercise and beta-blocker on blood pressure and baroreflexes in spontaneously hypertensive rats.
MedLine Citation:
PMID:  14573336     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Exercise training or beta-blocker decreases high blood pressure (BP) and improves abnormal baroreflex function associated with hypertension. This study was undertaken to examine whether the effects of exercise training are additive to beta-blocker in spontaneously hypertensive rats (SHR). METHODS: At 5 weeks of age, SHR were allocated to four groups: sedentary control, exercise training, treatment with moderate dose of bisoprolol, and their combination. Systolic BP was monitored by the tail-cuff method under restrained conditions. Sigmoidal mean arterial pressure (MAP)-heart rate (HR) reflex curves were obtained in rats at 17 weeks of age under quiet conditions before and after atenolol to ensure sympathetic blockade and to determine the vagal component of gain. After studying baroreflex function, intrinsic HR was obtained by additional administration of atropine. RESULTS: Before atenolol, both exercise training alone and bisoprolol alone lowered resting MAP and HR, and decreased upper plateau (maximal tachycardia) and lower plateau (maximal bradycardia), resulting in decreased sympathetic component of HR range (upper plateau - intrinsic HR) and increased vagal component of HR range (intrinsic HR - lower plateau). After atenolol, both exercise training alone and bisoprolol alone increased the gain of vagal component. Exercise training had no additive effect on any parameters to bisoprolol except for systolic BP and HR measured by the tail-cuff method. CONCLUSIONS: Exercise training and bisoprolol have similar effects concerning resting hemodynamics and baroreflex function in SHR. Although additive effects of exercise training to bisoprolol are not evident under quiet, nonstressful conditions, some additive effects may be obtained under stress such as restrain.
Authors:
Naoyoshi Minami; Takashi Yoshikawa; Hitomi Kataoka; Nobuyoshi Mori; Makoto Nagasaka; Hajime Kurosawa; Masayuki Kanazawa; Masahiro Kohzuki
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  American journal of hypertension     Volume:  16     ISSN:  0895-7061     ISO Abbreviation:  Am. J. Hypertens.     Publication Date:  2003 Nov 
Date Detail:
Created Date:  2003-10-23     Completed Date:  2004-02-26     Revised Date:  2009-02-24    
Medline Journal Info:
Nlm Unique ID:  8803676     Medline TA:  Am J Hypertens     Country:  United States    
Other Details:
Languages:  eng     Pagination:  966-72     Citation Subset:  IM    
Affiliation:
Department of Internal Medicine and Rehabilitation Science, Tohoku University Graduate School of Medicine, Sendai, Japan. minaoyo@mail.cc.tohoku.ac.jp
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MeSH Terms
Descriptor/Qualifier:
Adrenergic beta-Antagonists / pharmacology*
Animals
Atenolol / pharmacology
Baroreflex / drug effects*,  physiology
Bisoprolol / pharmacology*
Blood Pressure / drug effects*,  physiology
Body Weight
Heart Rate / drug effects
Hypertension / drug therapy*,  pathology,  physiopathology
Hypertrophy, Left Ventricular / pathology
Male
Physical Conditioning, Animal*
Rats
Rats, Inbred SHR
Tail
Chemical
Reg. No./Substance:
0/Adrenergic beta-Antagonists; 29122-68-7/Atenolol; 66722-44-9/Bisoprolol

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


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