Document Detail

Tonic activity in inspiratory muscles and phrenic motoneurons by stimulation of vagal afferents.
MedLine Citation:
PMID:  2732154     Owner:  NLM     Status:  MEDLINE    
In anesthetized rabbits, direct and integrated phrenic neurogram (Ephr) and electromyograms from the diaphragm (Edi) and intercostal (Eic) (2nd space) and transversus abdominis muscles (Etr) were simultaneously recorded in two protocols. 1) In animals breathing spontaneously, we used infinite inspiratory (RI) or expiratory (RE) resistive load and intravenous injections of carbachol, histamine, or phenyl diguanide (PDG). All circumstances except RE evoked tonic activities in Ephr, Edi, and Eic but never in Etr. Intravenous atropine abolished carbachol-induced bronchoconstriction and associated tonic inspiratory activities, but this effect persisted with RI, histamine, and PDG. Selective procaine block of conduction in thin vagal fibers (with persistence of the Breuer-Hering inflation reflex) reduced or suppressed the tonic response, which was abolished in all cases after vagotomy. 2) In rabbits artificially ventilated with open chest, passive deflation of the lung or intravenous injections of histamine or PDG also produced tonic discharge in Ephr and often in Eic. The present results demonstrate that 1) stimulation of vagal afferents and mostly thin sensory fibers elicits tonic inspiratory discharges, 2) bronchoconstriction is not necessary for the induction of the response, and 3) reflexes from the chest wall do not mediate this response in rabbits.
M Badier; Y Jammes; P Romero-Colomer; C Lemerre
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  66     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1989 Apr 
Date Detail:
Created Date:  1989-07-18     Completed Date:  1989-07-18     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1613-9     Citation Subset:  IM    
Laboratoire de Médecine Expérimentale, Faculté de Médecine, Marseille, France.
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MeSH Terms
Diaphragm / physiology*
Motor Neurons / physiology*
Neurons, Afferent / physiology*
Phrenic Nerve / physiology*
Respiratory Muscles / physiology*
Vagus Nerve / physiology*

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