Document Detail


Regional vascular resistance during exercise: role of cardiac afferents and exercise training.
MedLine Citation:
PMID:  2316698     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This study was designed to determine whether cardiac vagal afferents exert an inhibitory influence on increases in regional vascular resistance during exercise and to determine whether endurance exercise training enhances the inhibitory influence of cardiac vagal afferents. We measured changes in regional vascular resistance in 12 rabbits at rest and during running at 12.6 m/min, 20% grade, before and after reversible denervation of cardiac afferents (intrapericardial procainamide HCl, 2%). In addition, these procedures were repeated in five of these rabbits following an 8-wk endurance exercise training program. Because intrapericardial injections of procainamide anesthetize both the efferent as well as the afferent innervation to the heart, it was necessary to determine the effects of blocking the efferent innervation on the regulation of regional vascular resistance during exercise. Rabbits were instrumented with Doppler ultrasonic flow probes around the renal (R), mesenteric (M), ascending, and terminal aortic (TA) arteries. Catheters were positioned in the central ear artery and vein and pericardial sac. Mean arterial pressure, heart rate, cardiac output, R, M, TA, and systemic (S) resistances were determined. Exercise changed R (+37 +/- 4%), M (+88 +/- 9%), TA (-62 +/- 6%), and S (-34 +/- 3) resistances. Subsequent cardiac efferent blockade alone had no significant effect on regional vascular resistance during exercise. Combined efferent and afferent blockade resulted in significant increases in R (+62 +/- 6%) and M resistance (+134 +/- 13%) but did not alter TA (-51 +/- 4%) or S (-27 +/- 2%) resistance during exercise. Exercise training significantly enhanced the inhibitory influence of cardiac afferents on R and M regional vascular resistance.(ABSTRACT TRUNCATED AT 250 WORDS)
Authors:
S E DiCarlo; V S Bishop
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  258     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1990 Mar 
Date Detail:
Created Date:  1990-04-23     Completed Date:  1990-04-23     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H842-7     Citation Subset:  IM    
Affiliation:
Department of Pharmacology, University of Texas Health Science Center, San Antonio 78284-7764.
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MeSH Terms
Descriptor/Qualifier:
Afferent Pathways / physiology
Animals
Aorta / physiology
Blood Pressure
Efferent Pathways / physiology
Heart Conduction System / physiology*
Heart Rate
Nerve Block
Neurons, Afferent / physiology*
Physical Conditioning, Animal*
Physical Exertion*
Rabbits
Renal Circulation
Splanchnic Circulation
Vascular Resistance*
Grant Support
ID/Acronym/Agency:
HL-07598/HL/NHLBI NIH HHS; HL-12415/HL/NHLBI NIH HHS; HL-36080/HL/NHLBI NIH HHS

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


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