Document Detail

Baroreflex deficit blunts exercise training-induced cardiovascular and autonomic adaptations in hypertensive rats.
MedLine Citation:
PMID:  19930428     Owner:  NLM     Status:  MEDLINE    
1. Baroreceptors regulate moment-to-moment blood pressure (BP) variations, but their long-term effect on the cardiovascular system remains unclear. Baroreceptor deficit accompanying hypertension contributes to increased BP variability (BPV) and sympathetic activity, whereas exercise training has been associated with an improvement in these baroreflex-mediated changes. The aim of the present study was to evaluate the autonomic, haemodynamic and cardiac morphofunctional effects of long-term sinoaortic baroreceptor denervation (SAD) in trained and sedentary spontaneously hypertensive rats (SHR). 2. Rats were subjected to SAD or sham surgery and were then further divided into sedentary and trained groups. Exercise training was performed on a treadmill (five times per week, 50-70% maximal running speed). All groups were studied after 10 weeks. 3. Sinoaortic baroreceptor denervation in SHR had no effect on basal heart rate (HR) or BP, but did augment BPV, impairing the cardiac function associated with increased cardiac hypertrophy and collagen deposition. Exercise training reduced BP and HR, re-established baroreflex sensitivity and improved both HR variability and BPV. However, SAD in trained SHR blunted all these improvements. Moreover, the systolic and diastolic hypertensive dysfunction, reduced left ventricular chamber diameter and increased cardiac collagen deposition seen in SHR were improved after the training protocol. These benefits were attenuated in trained SAD SHR. 4. In conclusion, the present study has demonstrated that the arterial baroreflex mediates cardiac disturbances associated with hypertension and is crucial for the beneficial cardiovascular morphofunctional and autonomic adaptations induced by chronic exercise in hypertension.
I C Moraes-Silva; R N De La Fuente; C Mostarda; K Rosa; K Flues; N R Damaceno-Rodrigues; E G Caldini; K De Angelis; E M Krieger; M C Irigoyen
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-11-23
Journal Detail:
Title:  Clinical and experimental pharmacology & physiology     Volume:  37     ISSN:  1440-1681     ISO Abbreviation:  Clin. Exp. Pharmacol. Physiol.     Publication Date:  2010 Mar 
Date Detail:
Created Date:  2010-04-22     Completed Date:  2010-12-14     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0425076     Medline TA:  Clin Exp Pharmacol Physiol     Country:  Australia    
Other Details:
Languages:  eng     Pagination:  e114-20     Citation Subset:  IM    
Experimental Hypertension Laboratory, Hypertension Unit, Heart Institute, Sao Paulo, Brazil.
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MeSH Terms
Adaptation, Physiological / physiology*
Autonomic Denervation*
Baroreflex / physiology*
Heart Rate / physiology
Hypertension / physiopathology,  therapy*
Myocardial Contraction
Physical Conditioning, Animal* / methods
Pressoreceptors / physiology*,  surgery
Rats, Inbred SHR

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

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