Document Detail


Exercise pressor reflex in decerebrate and anesthetized rats.
MedLine Citation:
PMID:  12543631     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
I investigated whether muscular contraction evokes cardiorespiratory increases (exercise pressor reflex) in alpha-chloralose- and chloral hydrate-anesthetized and precollicular, midcollicular, and postcollicular decerebrated rats. Mean arterial pressure (MAP), heart rate (HR), and minute ventilation (Ve) were recorded before and during 1-min sciatic nerve stimulation, which induced static contraction of the triceps surae muscles, and during 1-min stretch of the calcaneal tendon, which selectively stimulated mechanosensitive receptors in the muscles. Anesthetized rats showed various patterns of MAP response to both stimuli, i.e., biphasic, depressor, pressor, and no response. Sciatic nerve stimulation to muscle in precollicular decerebrated rats always evoked spontaneous running, so the exercise pressor reflex was not determined from these preparations. None of the postcollicular decerebrated rats showed a MAP response or spontaneous running. Midcollicular decerebrated rats consistently showed biphasic blood pressure response to both stimulations. The increases in MAP, HR, and Ve were related to the tension developed. The static contractions in midcollicular decerebrated rats (381 +/- 65 g developed tension) significantly increased MAP, HR, and Ve from 103 +/- 12 to 119 +/- 24 mmHg, from 386 +/- 30 to 406 +/- 83 beats/min, and from 122 +/- 7 to 133 +/- 25 ml/min, respectively. After paralysis, sciatic nerve stimulation had no effect on MAP, HR, or Ve. These results indicate that the midcollicular decerebrated rat can be a model for the study of the exercise pressor reflex.
Authors:
Naoyuki Hayashi
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2003-01-23
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  284     ISSN:  0363-6135     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2003 Jun 
Date Detail:
Created Date:  2003-05-13     Completed Date:  2003-06-20     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H2026-33     Citation Subset:  IM    
Affiliation:
Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis 95616, USA. naohayashi@ans.hss.osaka-u.ac.jp
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MeSH Terms
Descriptor/Qualifier:
Anesthetics / pharmacology*
Anesthetics, Intravenous / pharmacology
Animals
Blood Pressure / physiology*
Carbon Dioxide / blood
Chloral Hydrate / pharmacology
Chloralose / pharmacology
Decerebrate State / physiopathology*
Female
Forelimb / blood supply,  physiology
Hindlimb / blood supply,  physiology
Hydrogen-Ion Concentration
Male
Oxygen / blood
Physical Exertion / physiology*
Rats
Rats, Sprague-Dawley
Regional Blood Flow / drug effects,  physiology
Respiratory Mechanics / physiology
Sciatic Nerve / physiology
Chemical
Reg. No./Substance:
0/Anesthetics; 0/Anesthetics, Intravenous; 124-38-9/Carbon Dioxide; 15879-93-3/Chloralose; 302-17-0/Chloral Hydrate; 7782-44-7/Oxygen

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