Document Detail


Epinephrine in the heart: uptake and release, but no facilitation of norepinephrine release.
MedLine Citation:
PMID:  12176961     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Several studies have suggested that epinephrine augments the release of norepinephrine from sympathetic nerve terminals through stimulation of presynaptic receptors, but evidence pertaining to this mechanism in the heart is scarce and conflicting. Using the microdialysis technique in the porcine heart, we investigated whether epinephrine, taken up by and released from cardiac sympathetic nerves, can increase norepinephrine concentrations in myocardial interstitial fluid (NE(MIF)) under basal conditions and during sympathetic activation. METHODS AND RESULTS: During intracoronary epinephrine infusion of 10, 50, and 100 ng/kg per minute under basal conditions, large increments in interstitial (from 0.31+/-0.05 up to 140+/-30 nmol/L) and coronary venous (from 0.16+/-0.08 up to 228+/-39 nmol/L) epinephrine concentrations were found, but NE(MIF) did not change. Left stellate ganglion stimulation increased NE(MIF) from 3.4+/-0.5 to 8.2+/-1.5 nmol/L, but again, this increase was not enhanced by concomitant intracoronary epinephrine infusion. Intracoronary infusion of tyramine resulted in a negligible increase in epinephrine concentration in myocardial interstitial fluid (EPI(MIF)), whereas 30 minutes after infusion of epinephrine an increase of 9.5 nmol/L in EPI(MIF) was observed, indicating that epinephrine is taken up by and released from cardiac sympathetic neurons. Although 68% to 78% of infused epinephrine was extracted over the heart, the ratio of interstitial to arterial epinephrine concentrations was only approximately 20%, increasing to 29% with neuronal reuptake inhibition. CONCLUSIONS: Our findings demonstrate epinephrine release from cardiac sympathetic neurons, but they do not provide evidence that epinephrine augments cardiac sympathoneural norepinephrine release under basal conditions or during sympathetic activation.
Authors:
Thomas W Lameris; Sandra de Zeeuw; Dirk J Duncker; Wouter Tietge; Gooitzen Alberts; Frans Boomsma; Pieter D Verdouw; Anton H van den Meiracker
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Circulation     Volume:  106     ISSN:  1524-4539     ISO Abbreviation:  Circulation     Publication Date:  2002 Aug 
Date Detail:
Created Date:  2002-08-14     Completed Date:  2002-10-16     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0147763     Medline TA:  Circulation     Country:  United States    
Other Details:
Languages:  eng     Pagination:  860-5     Citation Subset:  AIM; IM    
Affiliation:
Department of Internal Medicine, Cardiovascular Research Institute COEUR, Erasmus University Rotterdam, Rotterdam, The Netherlands.
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MeSH Terms
Descriptor/Qualifier:
Adrenergic Uptake Inhibitors / pharmacology
Adrenergic alpha-Antagonists / pharmacology
Animals
Coronary Vessels / physiology
Desipramine / pharmacology
Dose-Response Relationship, Drug
Electric Stimulation
Epinephrine / metabolism*,  pharmacokinetics
Extracellular Space / chemistry,  metabolism
Female
Heart / innervation
Hemodynamics / drug effects,  physiology
Infusions, Intra-Arterial
Male
Microdialysis
Myocardium / metabolism*
Norepinephrine / analysis,  metabolism*
Phentolamine / pharmacology
Stellate Ganglion / physiology
Swine
Sympathetic Nervous System / drug effects,  metabolism*
Tyramine / pharmacology
Chemical
Reg. No./Substance:
0/Adrenergic Uptake Inhibitors; 0/Adrenergic alpha-Antagonists; 50-47-5/Desipramine; 50-60-2/Phentolamine; 51-41-2/Norepinephrine; 51-43-4/Epinephrine; 51-67-2/Tyramine

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


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