Document Detail

In vitro hypoxia attenuates vasorelaxation by potassium channel opening drugs and nitroprusside in isolated pulmonary arteries from rats.
MedLine Citation:
PMID:  7965804     Owner:  NLM     Status:  MEDLINE    
The effects of in vitro hypoxia on relaxant responses to various vasodilator drugs were examined on norepinephrine-contracted ring preparations of rat pulmonary artery. The physiological salt solution that bathed the tissues was equilibrated with gas mixtures that contained 95%, 12%, 6%, 4% or 0% oxygen (oxygen tension of solution, > 650, 94, 44, 35 or < or = 11 mm Hg, respectively). Severe in vitro hypoxia (oxygen tension, 4 mm Hg) attenuated responses to pinacidil (negative log EC50 values: control, 5.61; hypoxia, 4.92). This effect of hypoxia was not prevented by endothelium removal or by indomethacin. Less severe hypoxia (oxygen tension < or = 35 mm Hg) attenuated responses to nitroprusside (negative log EC50: control, 8.34; hypoxia, 7.76). This effect of hypoxia was prevented by endothelium removal but not by indomethacin, NG-nitro-L-arginine methyl ester or the endothelin antagonist, cyclo(D-Trp-D-Asp-Pro-D-Val-Leu), and was not mimicked by endothelin. These effects of in vitro hypoxia were rapidly reversible and were distinct from the previously reported effects of chronic in vivo hypoxia on responses of pulmonary arteries to these drugs. It was also found that severe in vitro hypoxia abolished responses to acetylcholine and cromakalim and potentiated responses to sodium nitrite (negative log EC50: control, 3.79; hypoxia, 4.97) but had no effect on responses to colforsin (also known as forskolin).(ABSTRACT TRUNCATED AT 250 WORDS)
J C Wanstall
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of pharmacology and experimental therapeutics     Volume:  271     ISSN:  0022-3565     ISO Abbreviation:  J. Pharmacol. Exp. Ther.     Publication Date:  1994 Nov 
Date Detail:
Created Date:  1994-12-29     Completed Date:  1994-12-29     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0376362     Medline TA:  J Pharmacol Exp Ther     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  845-51     Citation Subset:  IM    
Department of Physiology and Pharmacology, University of Queensland, Brisbane, Australia.
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MeSH Terms
Cell Hypoxia*
Endothelins / pharmacology
Endothelium, Vascular / physiology
Guanidines / pharmacology*
Nitroprusside / pharmacology*
Potassium Channels / drug effects*
Pulmonary Artery / drug effects,  physiology
Rats, Wistar
Vasodilation / drug effects*
Vasodilator Agents / pharmacology*
Reg. No./Substance:
0/Endothelins; 0/Guanidines; 0/Potassium Channels; 0/Vasodilator Agents; 15078-28-1/Nitroprusside; 85371-64-8/Pinacidil

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

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