Document Detail

Relative contribution of different vascular beds to the pressor effects of alpha-adrenoreceptor agonists and vasopressin in pithed rats: radioactive microsphere determination.
MedLine Citation:
PMID:  2869044     Owner:  NLM     Status:  MEDLINE    
The relative fractional distribution of 51Cr-labelled microspheres was evaluated in pithed rats during equieffective vascoconstrictor responses evoked by infusions of the alpha-adrenoreceptor agonists methoxamine (alpha 1-selective), UK-14,304 (alpha 2-selective) or vasopressin. The proportion of injected radioactive microspheres trapped in each tissue during a sustained pressor response relative to saline treated controls is considered a reflection of the degree of local vascoconstriction in the tissue analysed. All three agonists (methoxamine, UK-14,304 and vasopressin) decreased the number of microspheres trapped in the mesentery and tail. Only methoxamine reduced the blood flow to the kidney and spleen. UK-14,304 did not modify the number of microspheres in the sample of skeletal muscle, however, both vasopressin and methoxamine reduced the blood flow to this tissue. Vasopressin increased the counts in the lungs and particularly in the liver but decreased the number of spheres trapped in the stomach and skin. In contrast to the alpha-adrenoreceptor agonists, vasopressin did not increase the number of microspheres trapped in the heart. Since a reduction in the number of microspheres trapped in the tissue reflects a decrease in blood flow, to that organ it is reasonable to conclude that alpha 1-adrenoreceptor stimulation increases kidney, spleen, mesentery, caudal and skeletal muscle vascular resistance, whereas alpha 2-adrenoreceptors appear to preferentially vasoconstrict the mesenteric and the caudal vascular beds.
C J Waldron; P E Hicks
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of autonomic pharmacology     Volume:  5     ISSN:  0144-1795     ISO Abbreviation:  J Auton Pharmacol     Publication Date:  1985 Dec 
Date Detail:
Created Date:  1986-03-31     Completed Date:  1986-03-31     Revised Date:  2003-11-14    
Medline Journal Info:
Nlm Unique ID:  8106455     Medline TA:  J Auton Pharmacol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  333-8     Citation Subset:  IM    
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MeSH Terms
Adrenergic alpha-Agonists / pharmacology*
Blood Pressure / drug effects*
Chromium Radioisotopes / diagnostic use
Decerebrate State
Methoxamine / pharmacology
Quinoxalines / pharmacology
Rats, Inbred Strains
Vasoconstriction / drug effects
Vasopressins / pharmacology*
Reg. No./Substance:
0/Adrenergic alpha-Agonists; 0/Chromium Radioisotopes; 0/Quinoxalines; 11000-17-2/Vasopressins; 390-28-3/Methoxamine; 59803-98-4/brimonidine

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

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