Document Detail


Contrasting reflex effects of chemosensitive and mechanosensitive vagal afferents.
MedLine Citation:
PMID:  3391679     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Previous studies have identified two distinct types of cardiac vagal afferents, mechanosensitive and chemosensitive. We tested the hypothesis that these two types of vagal afferents mediate different reflex sympathetic nerve responses. We compared effects of stimulation of chemosensitive and mechanosensitive vagal afferents on renal and adrenal sympathetic nerve activity in rats. In anesthetized, sinoaortic baroreceptor-denervated rats, we measured arterial pressure, heart rate, and renal and adrenal sympathetic nerve activity during intrapericardial administration of phenyl diguanide as a stimulus for chemosensitive afferents and during volume expansion and acute occlusion of the ascending aorta as stimuli for mechanosensitive afferents. Stimulation of chemosensitive afferents with phenyl diguanide (3, 10, and 30 micrograms/kg intrapericardially) caused decreases in renal sympathetic nerve activity (-36 +/- 5, -52 +/- 11, and -71 +/- 5%; p less than 0.01) and in arterial pressure and heart rate but increased adrenal sympathetic nerve activity (+14 +/- 27, +63 +/- 21, and +83 +/- 28%; p less than 0.05). These responses were abolished by vagotomy. Intrapericardial injection of saline vehicle did not change renal and adrenal sympathetic nerve activity. In contrast to the effects of phenyl diguanide, activation of mechanosensitive afferents by volume expansion with intravenous infusion of 6% dextran in 0.9% saline (Dextran 75) decreased both renal and adrenal sympathetic nerve activity. Stimulation of mechanosensitive afferents by acute occlusion of the ascending aorta also decreased both renal and adrenal sympathetic nerve activity. These results indicate that chemosensitive and mechanosensitive cardiac vagal afferents produce different reflex responses: Chemosensitive afferents increase and mechanosensitive afferents decrease adrenal sympathetic outflow.
Authors:
S Higuchi; D A Morgan; A L Mark
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Hypertension     Volume:  11     ISSN:  0194-911X     ISO Abbreviation:  Hypertension     Publication Date:  1988 Jun 
Date Detail:
Created Date:  1988-08-24     Completed Date:  1988-08-24     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  7906255     Medline TA:  Hypertension     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  674-9     Citation Subset:  IM; S    
Affiliation:
Veterans Administration Medical Center, Iowa City, Iowa.
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MeSH Terms
Descriptor/Qualifier:
Adrenal Glands / innervation
Animals
Biguanides / pharmacology*
Blood Volume
Chemoreceptor Cells / drug effects,  physiology*
Female
Hemodynamics / drug effects
Kidney / innervation
Nitroprusside / pharmacology
Pressoreceptors / drug effects,  physiology*
Rats
Rats, Inbred Strains
Stress, Mechanical
Vagotomy
Vagus Nerve / drug effects,  physiology*
Grant Support
ID/Acronym/Agency:
HL 14388/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Biguanides; 102-02-3/phenyl biguanide; 15078-28-1/Nitroprusside

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


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