Document Detail


Excitation of the cardiac vagus by vasopressin in mammals.
MedLine Citation:
PMID:  6481644     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In unanaesthetized sheep, the sensitivity of the baroreceptor-cardio-inhibitory reflex was greater when intravenous vasopressin was used to raise blood pressure, than when intravenous phenylephrine was used to raise blood pressure. This difference was still evident in animals in which beta-adrenergic blockade had been carried out using propranolol. In the presence of combined beta-adrenergic and muscarinic blockade, a direct negative chronotropic effect of intravenous vasopressin could not be demonstrated. It was concluded, therefore, that intravenous vasopressin enhanced cardiac vagal tone. This effect of vasopressin on efferent cardiac vagal tone was confirmed directly in anaesthetized dogs by recording from single cardiac vagal efferent fibres. Furthermore, recordings from single carotid sinus baroreceptor fibres did not demonstrate a direct action of vasopressin on the sensitivity of the baroreceptors. However, the pressor effect of vasopressin is associated with a greater increase in efferent cardiac vagal discharge than that seen when equipressor doses of phenylephrine are given, or when blood pressure is raised by a similar amount by inflation of an intra-aortic balloon. Studies in isolated guinea-pig atrial preparations and in anaesthetized rabbits and dogs, revealed no consistent peripheral action of vasopressin on the action of the vagus at the heart.
Authors:
G P Courtice; T E Kwong; E R Lumbers; E K Potter
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of physiology     Volume:  354     ISSN:  0022-3751     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  1984 Sep 
Date Detail:
Created Date:  1984-11-13     Completed Date:  1984-11-13     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  547-56     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Action Potentials / drug effects
Animals
Blood Pressure / drug effects
Dogs
Guinea Pigs
Heart / innervation*
Heart Rate / drug effects
Phenylephrine / pharmacology
Pressoreceptors / physiology
Propranolol / pharmacology
Rabbits
Reflex / physiology
Sheep
Vagus Nerve / drug effects,  physiology*
Vasopressins / pharmacology*
Chemical
Reg. No./Substance:
11000-17-2/Vasopressins; 525-66-6/Propranolol; 59-42-7/Phenylephrine
Comments/Corrections

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


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