Document Detail

Postexercise alpha-adrenergic receptor hyporesponsiveness in hypertensive rats is due to nitric oxide.
MedLine Citation:
PMID:  11893598     Owner:  NLM     Status:  MEDLINE    
We tested the hypothesis that a single bout of dynamic exercise produces a postexercise hypotension (PEH) and alpha(1)-adrenergic receptor hyporesponsiveness in spontaneously hypertensive rats (SHR). The postexercise alpha(1)-adrenergic receptor hyporesponsiveness is due to an enhanced buffering of vasoconstriction by nitric oxide. Male (n = 8) and female (n = 5) SHR were instrumented with a Doppler ultrasonic flow probe around the femoral artery. Distal to the flow probe, a microrenathane catheter was inserted into a branch of the femoral artery for the infusion of the alpha(1)-adrenergic receptor agonist phenylephrine (PE). A microrenathane catheter was inserted into the descending aorta via the left common carotid artery for measurements of arterial pressure (AP) and heart rate. Dose-response curves to PE (3.8 x 10(-3) - 1.98 x 10(-2)microg/kHz) were generated before and after a single bout of dynamic exercise. Postexercise AP was reduced in male (13 +/- 3 mmHg) and female SHR (18 +/- 7 mmHg). Postexercise vasoconstrictor responses to PE were reduced in males due to an enhanced influence of nitric oxide. However, in females, postexercise vasoconstrictor responses to PE were not altered. Results suggest that nitric oxide- mediated alpha(1)-adrenergic receptor hyporesponsiveness contributes to PEH in male but not female SHR.
Sumangala P Rao; Heidi L Collins; Stephen E DiCarlo
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  American journal of physiology. Regulatory, integrative and comparative physiology     Volume:  282     ISSN:  0363-6119     ISO Abbreviation:  Am. J. Physiol. Regul. Integr. Comp. Physiol.     Publication Date:  2002 Apr 
Date Detail:
Created Date:  2002-03-14     Completed Date:  2002-04-16     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  100901230     Medline TA:  Am J Physiol Regul Integr Comp Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  R960-8     Citation Subset:  IM    
Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
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MeSH Terms
Adrenergic alpha-Agonists / pharmacology
Blood Flow Velocity / physiology
Blood Pressure / physiology
Femoral Artery / physiology
Heart Rate / physiology
Hypertension / metabolism*
Laser-Doppler Flowmetry
Nitric Oxide / metabolism*
Phenylephrine / pharmacology
Physical Exertion / physiology*
Receptors, Adrenergic, alpha-1 / metabolism*
Sex Factors
Vasoconstriction / drug effects,  physiology
Grant Support
Reg. No./Substance:
0/Adrenergic alpha-Agonists; 0/Receptors, Adrenergic, alpha-1; 10102-43-9/Nitric Oxide; 59-42-7/Phenylephrine

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