Document Detail


Electrically induced static exercise elicits a pressor response in the decerebrate rat.
MedLine Citation:
PMID:  11744768     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
1. The purpose of this investigation was to determine if activation of the exercise pressor reflex in the decerebrate rat induced circulatory responses comparable to those reported in large mammalian species. 2. To activate both mechanically and metabolically sensitive afferent fibres, static hindlimb contractions were induced by stimulating the cut ends of L4 and L5 spinal ventral roots in Sprague-Dawley rats (300-400 g). To selectively stimulate mechanically sensitive receptors, hindlimb muscles were passively stretched. 3. In intact halothane-anaesthetized animals (n = 10), static contraction and passive stretch induced a decrease in mean arterial pressure (Delta MAP = -17 +/- 3 and -8 +/- 1 mmHg for contraction and stretch, respectively) and heart rate (HR). In contrast, MAP increased 23 +/- 2 mmHg during contraction and 19 +/- 3 mmHg during stretch in decerebrate rats (n = 10). These pressor responses were accompanied by a significant tachycardia. In decerebrate animals, the reintroduction of halothane attenuated the increase in MAP and HR caused by both contraction and stretch. 4. In both anaesthetized and decerebrate rats, sectioning the spinal dorsal roots innervating the activated skeletal muscle eliminated responses to contraction and stretch. This finding indicated that an intramuscular neural reflex mediated the response to each stimulus. 5. The results demonstrate that a decerebrate preparation in the rat is a reliable model for the study of the exercise pressor reflex. Development of the model would enable the study of this reflex in a variety of pathological conditions and allow investigation of the mechanisms controlling cardiovascular responses to exercise in health and disease.
Authors:
S A Smith; J H Mitchell; M G Garry
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of physiology     Volume:  537     ISSN:  0022-3751     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  2001 Dec 
Date Detail:
Created Date:  2001-12-17     Completed Date:  2002-03-19     Revised Date:  2013-06-09    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  961-70     Citation Subset:  IM    
Affiliation:
Harry S. Moss Heart Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75390-9174, USA. scott.smith@utsouthwestern.edu
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MeSH Terms
Descriptor/Qualifier:
Animals
Baroreflex / physiology
Blood Pressure / physiology*
Cardiovascular Physiological Phenomena
Decerebrate State / physiopathology*
Electric Stimulation
Male
Motor Activity / physiology*
Rats
Rats, Sprague-Dawley
Sciatic Nerve / physiopathology
Spinal Nerve Roots / physiopathology
Stress, Mechanical
Grant Support
ID/Acronym/Agency:
HL-06296/HL/NHLBI NIH HHS; HL-10473/HL/NHLBI NIH HHS
Comments/Corrections

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