Document Detail


Behavior of cardiac receptors with nonmyelinated vagal afferents during spontaneous respiration in cats.
MedLine Citation:
PMID:  908115     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Activity from left atrial and left ventricular receptors with nonmyelinated vagal afferents (mean conduction velocity, 1.2 m/sec) was recorded in 13 closed-chest spontaneously breathing cats anesthetized with alpha-chloralose. The anatomic position of each receptor was determined by probing the opened heart at the conclusion of the experiment. Three of eight left atrial receptors and four of five left ventricular receptors were silent under resting conditions. The mean discharge frequency under resting conditons for the six receptors displaying spontaneous activity was 1.0 +/- 0.15 impulse/sec. Thus cardiac receptors with vagal nonmyelinated afferent have a low resting discharge in spontaneously breathing cats. The frequency and pattern of discharge of atrial but not of ventricular receptors was altered during spontaneous respiration. The atrial receptors discharged with cardiac rhythmicity during end inspiration and early expiration when transmural pressure was greatest and were silent for the remainder of the respiratory cycle. Whe respiration was augmented by CO2 breathing or blood volume was increased, the rate of discharge was a linear function of atrial transmural pressure. Eleven ventricular receptors with nonmyelinated afferents (mean conduction velocity, 1.0 m/sec) were exposed to graded volume expansion and phenylephrine infusion in eight open-chest and three spontaneously breathing cats. Raising left ventricular end-diastolic pressure alone increased the frequency of discharge, and a concomitant increase in systolic pressure caused a further increase in firing.
Authors:
M D Thames; D E Donald; J T Shepherd
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Circulation research     Volume:  41     ISSN:  0009-7330     ISO Abbreviation:  Circ. Res.     Publication Date:  1977 Nov 
Date Detail:
Created Date:  1977-11-30     Completed Date:  1977-11-30     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0047103     Medline TA:  Circ Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  694-701     Citation Subset:  IM; S    
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood Volume
Carbon Dioxide
Cats
Heart / innervation*
Mechanoreceptors / physiology*
Nerve Fibers / physiology*
Neural Conduction
Neurons, Afferent / physiology*
Respiration
Vagus Nerve / physiology*
Chemical
Reg. No./Substance:
124-38-9/Carbon Dioxide

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


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