Document Detail

Prolonged exercise alters beta-adrenergic responsiveness in healthy sedentary humans.
MedLine Citation:
PMID:  8929606     Owner:  NLM     Status:  MEDLINE    
To examine whether beta-adrenergic desensitization occurs after prolonged exercise, echocardiograms, heart rate responses to isoproterenol, plasma catecholamines, and circulating lymphocyte beta-adrenergic receptors were examined in 10 sedentary normal subjects at rest and after brief (10 min) and exhaustive (mean duration 95 min) cycle exercise. Resting end-diastolic volume and ejection fraction were significantly reduced after exercise (from 120 +/- 34 to 100 +/- 26 ml and from 60 +/- 0.4 to 54 +/- 0.6%, respectively; both P < 0.05). The amount of isoproterenol needed to increase heart rate 15 and 25 beats/min increased in a dose- (exercise duration) related fashion, and the increase in amount of isoproterenol needed after prolonged exercise was closely related to the decrease in ejection fraction (r2 = 0.67, P = 0.004). Circulating lymphocyte beta-receptor density and affinity, agonist binding, and adenylylcyclase levels were unchanged with prolonged exercise. In conclusion, prolonged exercise in sedentary normal subjects resulted in reduced cardiac chronotropic responsiveness to isoproterenol that was not reflected in peripheral lymphocyte beta-adrenergic-receptor downregulation.
S B Eysmann; E Gervino; D E Vatner; S E Katz; L Decker; P S Douglas
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Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  80     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1996 Feb 
Date Detail:
Created Date:  1997-02-06     Completed Date:  1997-02-06     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  616-22     Citation Subset:  IM    
Charles A. Dana Research Institute and Harvard-Thorndike Laboratory, Department of Medicine, Beth Israel Hospital, Boston 02215, USA.
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MeSH Terms
Adenylate Cyclase / metabolism
Adrenergic beta-Agonists / administration & dosage,  pharmacology
Catecholamines / blood
Down-Regulation / physiology
Echocardiography, Doppler
Exercise / physiology*
Exercise Test
Injections, Intravenous
Iodine Radioisotopes / diagnostic use
Isoproterenol / administration & dosage,  pharmacology
Lymphocytes / drug effects,  physiology
Middle Aged
Myocardium / enzymology
Radioligand Assay
Receptors, Adrenergic, beta / physiology*
Ventricular Function, Left / drug effects,  physiology
Grant Support
Reg. No./Substance:
0/Adrenergic beta-Agonists; 0/Catecholamines; 0/Iodine Radioisotopes; 0/Receptors, Adrenergic, beta; 7683-59-2/Isoproterenol; EC Cyclase

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