Document Detail


Abolition of clonidine's effects on ventricular refractoriness by naloxone in the conscious dog.
MedLine Citation:
PMID:  2770406     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The interaction between opiate and adrenergic receptors on cardiac electrophysiologic function in the conscious dog was addressed in our study. We examined the effects of opiate receptor blockade with naloxone on clonidine-induced changes in refractoriness of the cardiac ventricle. Nine dogs were chronically instrumented for recording mean arterial blood pressure, administration of drugs and for measurement of effective refractory period of the ventricle. Clonidine (10 micrograms/kg, i.v.) significantly (p less than 0.05) decreased heart rate to 72 +/- 5 beats/minute from 108 +/- 8 beats/minute; mean arterial pressure decreased significantly (p less than 0.05) to 83 +/- 3 mmHg from 91 +/- 4 mmHg. Ventricular refractoriness was increased significantly (p less than 0.05) at current levels of 7 and 10 mA and pacing rates 180 and 200 beats/minute. Naloxone (3-10 mg/kg, i.v.) abolished clonidine's effects on heart rate, mean arterial pressure and ventricular refractoriness. We conclude that ventricular refractoriness may be regulated in part by interactions between central adrenergic and opioidergic systems.
Authors:
J M Pinto; D A Kirby; R L Verrier
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Life sciences     Volume:  45     ISSN:  0024-3205     ISO Abbreviation:  Life Sci.     Publication Date:  1989  
Date Detail:
Created Date:  1989-09-25     Completed Date:  1989-09-25     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0375521     Medline TA:  Life Sci     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  413-20     Citation Subset:  IM    
Affiliation:
Department of Nutrition, Harvard School of Public Health, Boston, MA 02115.
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood Pressure / drug effects*
Clonidine / antagonists & inhibitors,  pharmacology*
Dogs
Female
Heart Rate / drug effects*
Male
Naloxone / pharmacology*
Reference Values
Time Factors
Grant Support
ID/Acronym/Agency:
HL-35138/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
4205-90-7/Clonidine; 465-65-6/Naloxone

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


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