Document Detail

Mechanism of the cardiovascular response to systemic intravenous administration of leucine-enkephalin in the conscious dog.
MedLine Citation:
PMID:  6137809     Owner:  NLM     Status:  MEDLINE    
Leucine-enkephalin (Leu5-ENK) (35 micrograms/kg) increased heart rate and mean systemic arterial blood pressure following intravenous injection into chronically-instrumented, conscious dogs. Repeated injections at five-minute intervals were not associated with a diminished response. Naloxone (1 mg/kg) pre-treatment inhibited both heart rate and blood pressure increases. Prazosin (1 mg/kg) attenuated the increase in blood pressure but did not influence the heart rate response. Propranolol (1 mg/kg) attenuated the heart rate response but not the pressor response. Clonidine (30 micrograms/kg) attenuated the positive chronotropic effect of Leu5-ENK. Atropine (1 mg/kg) plus propranolol (1 mg/kg) blocked the heart rate response but the pressor effect was still present. The attenuation of the heart rate response by propranolol and the pressor response by prazosin suggests an adrenergic component to the enkephalin response; the reduction in the heart rate response by clonidine and atropine-propranolol indicates a role for cholinergic mechanisms in the chronotropic response. Hexamethonium (10 mg/kg) blocked the heart rate response and markedly inhibited the pressor response. Vagal interruption attenuated both heart rate and blood pressure responses. It is concluded that intravenous Leu5-ENK stimulates afferent pathways located in fibers which are contained in the vagosympathetic trunk to reflexly increase heart rate and blood pressure.
T D Giles; G E Sander
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Peptides     Volume:  4     ISSN:  0196-9781     ISO Abbreviation:  Peptides     Publication Date:    1983 Mar-Apr
Date Detail:
Created Date:  1983-11-23     Completed Date:  1983-11-23     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8008690     Medline TA:  Peptides     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  171-5     Citation Subset:  IM    
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MeSH Terms
Blood Pressure / drug effects*
Clonidine / pharmacology
Consciousness / physiology
Drug Interactions
Enkephalin, Leucine / administration & dosage,  pharmacology*
Heart Rate / drug effects*
Hexamethonium Compounds / pharmacology
Injections, Intravenous
Naloxone / pharmacology
Prazosin / pharmacology
Propranolol / pharmacology
Reg. No./Substance:
0/Hexamethonium Compounds; 19216-56-9/Prazosin; 4205-90-7/Clonidine; 465-65-6/Naloxone; 525-66-6/Propranolol; 58822-25-6/Enkephalin, Leucine; 60-26-4/Hexamethonium

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

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