Document Detail


Amelioration of depressed cardiopulmonary reflex control of sympathetic nerve activity by short-term exercise training in male rabbits with heart failure.
MedLine Citation:
PMID:  12857767     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The reflex regulation of sympathetic nerve activity has been demonstrated to be impaired in the chronic heart failure (CHF) state compared with the normal condition (Liu JL, Murakami H, and Zucker IH. Circ Res 82: 496-502, 1998). Exercise training (Ex) appears to be beneficial to patients with CHF and has been shown to reduce sympathetic outflow in this disease state (Hambrecht R, Hilbrich L, Erbs S, Gielen S, Fiehn E, Schoene N, and Schuler G. J Am Coll Cardiol 35: 706-713, 2000). We tested the hypothesis that Ex corrects the reduced cardiopulmonary (CP) reflex response to volume expansion in the CHF state. Normal, normal with Ex, CHF, and CHF with Ex (CHF-Ex) groups (n = 10-21) of male New Zealand White rabbits were studied. CHF was induced by chronic ventricular pacing. Rabbits were instrumented to record left ventricular end-diastolic pressure (LVEDP), left ventricular end-diastolic diameter (LVEDD), and renal sympathetic nerve activity (RSNA). Experiments were carried out with the animals in the conscious state. Volume expansion was performed with 6% dextran in normal saline at a rate of 5 ml/min to approximately 20% of estimated plasma volume without any significant effect on mean arterial pressure being exhibited. The relationships between RSNA and LVEDP and between RSNA and LVEDD were determined by linear regression; the slopes served as an index of CP reflex sensitivity. Normal rabbits exhibited a CP reflex sensitivity of -8.4 +/- 1.5%delta RSNA/mmHg. This value fell to 0.0 +/- 1.3%delta RSNA/mmHg in CHF rabbits (P < 0.001). Ex increased CP reflex sensitivity to -5.0 +/- 0.7%delta RSNA/mmHg in CHF-Ex rabbits (P < 0.05 compared with CHF). A similar trend was seen when related to the change in LVEDD. Furthermore, resting RSNA expressed as a percentage of maximum RSNA in response to cigarette smoke was also normalized by Ex in rabbits with CHF. Ex had no effect on these parameters in normal rabbits. These data confirm an impairment of CP reflex sensitivity and sympathoexcitation in CHF vs. normal animals. Ex substantially restored both CP reflex sensitivity and baseline RSNA in CHF animals. Thus Ex beneficially affects reflex regulation in CHF, thereby lowering resting sympathetic nerve activity.
Authors:
R U Pliquett; K G Cornish; K P Patel; H D Schultz; J D Peuler; I H Zucker
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.     Date:  2003-07-11
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  95     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2003 Nov 
Date Detail:
Created Date:  2003-10-13     Completed Date:  2004-06-15     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1883-8     Citation Subset:  IM    
Affiliation:
Department of Physiology and Biophysics, University of Nebraska Medical Center, Omaha, Nebraska 68198-4575, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood Pressure / physiology
Catecholamines / blood
Heart Failure / physiopathology*
Heart Rate / physiology
Kidney / innervation,  physiology
Lung / physiology
Male
Physical Conditioning, Animal / physiology*
Rabbits
Reflex / physiology*
Sympathetic Nervous System / physiology*
Ventricular Pressure / physiology
Grant Support
ID/Acronym/Agency:
HL-38690/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Catecholamines

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


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