Document Detail

Exercise training prevents the exaggerated exercise pressor reflex in rats with chronic heart failure.
MedLine Citation:
PMID:  20185628     Owner:  NLM     Status:  MEDLINE    
An exaggerated exercise pressor reflex (EPR) occurs in the chronic heart failure (CHF) state, which contributes to exercise intolerance and excessive sympathoexcitation during exercise. Exercise training (ExT) improves abnormal cardiovascular reflexes in CHF. Whether ExT can normalize the exaggerated EPR function remains to be determined. This study was designed to investigate the effects of ExT on the EPR and on the mechanical or metabolic components of this reflex in sham-operated and CHF rats. The EPR was activated by static contraction induced by electrical stimulation of L4/L5 ventral roots. The afferent fibers associated with the mechanoreflex and metaboreflex were activated by passive stretch and hindlimb arterial injection of capsaicin (0.1 and 1 microg/kg, 0.2 ml), respectively. Heart rate, blood pressure, and sympathoexcitatory responses during the activation of these reflexes were compared in sham+sedentary (Sed), sham+ExT, CHF+Sed, and CHF+ExT rats. Compared with sham+Sed rats, CHF+Sed rats exhibited exaggerated heart rate and pressor and sympathoexcitatory responses to either static contraction or passive stretch, whereas the cardiovascular responses to injection of capsaicin were blunted. Eight to ten weeks of ExT normalized the exaggerated responses induced by static contraction or passive stretch and partially improved the blunted responses due to intra-arterial capsaicin in CHF rats. ExT had no significant effect on the EPR and mechanoreflex and metaboreflex functions in sham rats. These findings suggest a potential therapeutic role for ExT in minimizing arterial pressure and sympathetic outflow following activation of the EPR in the CHF state.
Han-Jun Wang; Yan-Xia Pan; Wei-Zhong Wang; Lie Gao; Matthew C Zimmerman; Irving H Zucker; Wei Wang
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2010-02-25
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  108     ISSN:  1522-1601     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2010 May 
Date Detail:
Created Date:  2010-05-05     Completed Date:  2010-08-12     Revised Date:  2014-09-19    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1365-75     Citation Subset:  IM    
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MeSH Terms
Baroreflex* / drug effects
Blood Pressure
Capsaicin / pharmacology
Cardiovascular System / innervation*
Chronic Disease
Disease Models, Animal
Electric Stimulation
Exercise Tolerance*
Heart Failure / metabolism,  physiopathology*,  ultrasonography
Heart Rate
Kidney / innervation
Muscle Contraction
Muscle, Skeletal / innervation*,  metabolism
Physical Exertion*
Rats, Sprague-Dawley
Sensory System Agents / pharmacology
Spinal Nerve Roots / physiopathology
Sympathetic Nervous System / physiopathology
Grant Support
P01 H62222//PHS HHS; R01 HL093028/HL/NHLBI NIH HHS
Reg. No./Substance:
0/Sensory System Agents; S07O44R1ZM/Capsaicin

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