Document Detail


Effects of chronic systemic hypoxia on contraction evoked by noradrenaline in the rat iliac artery.
MedLine Citation:
PMID:  12861337     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Comparisons were made between responses evoked by noradrenaline (NA) in iliac artery rings from normoxic (N) rats and chronically hypoxic (CH) rats kept in 12 % O(2) for 3-4 weeks. At P(O(2)) of 100 mmHg, cumulative concentration-response curves (CCRC) to NA were greatly depressed in endothelium-intact (E+) rings, but not endothelium-denuded (E-) rings, of CH rats relative to N rats. However, CCRCs evoked by NA in E+ and E- rings during nitric oxide (NO) synthase inhibition were similar in N and CH rats. Reducing P(O(2)) to 55 mmHg depressed CCRCs to NA in E+ and E- rings of CH and N rats in the absence and presence of NO synthase inhibition. At P(O(2)) of 100 mmHg, CCRCs evoked by phenylephrine were comparable in E+ and E- rings of N and CH rats as were CCRCs for the relaxation evoked by isoprenaline, which were similarly rightward shifted by NO synthase inhibition. However, CCRCs evoked by the NO donor sodium nitroprusside were leftward shifted in E- rings of CH rats relative to N rats. Further, in the presence of the alpha(2) adrenoceptor inhibitor rauwolscine, CCRCs to NA were comparable in E+ rings of CH and N rats. Thus, the depressive effects of chronic hypoxia on NA-evoked contractions of iliac artery are additional to those of acute hypoxia. We propose that they reflect a facilitation of the contribution of NO to alpha(2) adrenoceptor-evoked relaxation that includes an increased sensitivity of the vascular smooth muscle of arteries from CH rats to NO.
Authors:
I S Bartlett; Janice M Marshall
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Experimental physiology     Volume:  88     ISSN:  0958-0670     ISO Abbreviation:  Exp. Physiol.     Publication Date:  2003 Jul 
Date Detail:
Created Date:  2003-07-15     Completed Date:  2004-09-16     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9002940     Medline TA:  Exp Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  497-507     Citation Subset:  IM    
Affiliation:
Department of Physiology, Division of Medical Sciences, The Medical School, Birmingham B15 2TT, UK.
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MeSH Terms
Descriptor/Qualifier:
Adrenergic alpha-Antagonists / pharmacology
Adrenergic beta-Agonists / pharmacology
Animals
Anoxia / physiopathology*
Carbon Dioxide / blood
Chronic Disease
Dose-Response Relationship, Drug
Enzyme Inhibitors / pharmacology
Iliac Artery / drug effects,  physiology*
Isoproterenol / pharmacology
Muscle, Smooth, Vascular / drug effects,  physiology*
NG-Nitroarginine Methyl Ester / pharmacology
Nitroprusside / pharmacology
Norepinephrine / pharmacology
Oxygen / blood
Phenylephrine / pharmacology
Potassium / pharmacology
Rats
Receptors, Adrenergic, alpha / physiology
Vasoconstriction / drug effects,  physiology*
Vasoconstrictor Agents / pharmacology
Vasodilator Agents / pharmacology
Yohimbine / pharmacology
Chemical
Reg. No./Substance:
0/Adrenergic alpha-Antagonists; 0/Adrenergic beta-Agonists; 0/Enzyme Inhibitors; 0/Receptors, Adrenergic, alpha; 0/Vasoconstrictor Agents; 0/Vasodilator Agents; 124-38-9/Carbon Dioxide; 146-48-5/Yohimbine; 15078-28-1/Nitroprusside; 50903-99-6/NG-Nitroarginine Methyl Ester; 51-41-2/Norepinephrine; 59-42-7/Phenylephrine; 7440-09-7/Potassium; 7683-59-2/Isoproterenol; 7782-44-7/Oxygen

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


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