Document Detail


Mechanisms of protection afforded by preconditioning to endothelial function against ischemic injury.
MedLine Citation:
PMID:  8945894     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The aim of this study was to assess whether the cardioprotective effect of ischemic preconditioning (IPC) on endothelial function in resistance coronary arteries of the rat involves adenosine and/or activation of ATP-sensitive K+ channels (KATP channels). Isolated rat hearts perfused under constant-flow conditions were exposed to 30 min of partial ischemia (flow rate 1 ml/min) followed by 20 min of reperfusion. Preconditioning was performed with 5 min of ischemia and 10 min of reperfusion before the 30-min ischemia. After the 20-min reperfusion period, coronary arteries were precontracted with U-46619 (0.1 microM), and the coronary response to the endothelium-dependent vasodilator serotonin (5-HT; 10 microM) was compared with that of the endothelium-independent vasodilator sodium nitroprusside (SNP; 3 microM). KATP channels or adenosine receptors were blocked with perfusion of either glibenclamide (0.3 microM) or 8-phenyltheophylline (8-PT; 5 microM), respectively, starting 15 min before IPC or a corresponding sham period. In untreated hearts, ischemia selectively diminished 5-HT-induced vasodilation, compared with sham hearts (without ischemia). The vasodilation by SNP was unaffected after ischemia and reperfusion. Preconditioning in untreated hearts preserved the vasodilation produced by 5-HT. Treatment of hearts with either glibenclamide or 8-PT halved the vasodilation produced by both 5-HT and SNP in sham hearts. Glibenclamide reduced by one-half, whereas 8-PT completely blocked, the protective effect of IPC on endothelium-dependent vasodilation. These results suggest that IPC affords protection to endothelial function in resistance coronary arteries of the rat partially by activation of KATP channels. Adenosine plays a major role in that protection.
Authors:
J F Bouchard; D Lamontagne
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The American journal of physiology     Volume:  271     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1996 Nov 
Date Detail:
Created Date:  1997-01-03     Completed Date:  1997-01-03     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H1801-6     Citation Subset:  IM    
Affiliation:
Faculté de Pharmacie, Université de Montréal, Quebec, Canada.
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MeSH Terms
Descriptor/Qualifier:
Adenosine Triphosphate / pharmacology
Animals
Coronary Vessels / drug effects,  physiopathology
Endothelium, Vascular / physiopathology*
Glyburide / pharmacology
Ischemic Preconditioning, Myocardial*
Male
Myocardial Ischemia / physiopathology*
Potassium Channel Blockers
Potassium Channels / drug effects
Rats
Rats, Sprague-Dawley
Receptors, Purinergic P1 / antagonists & inhibitors
Theophylline / analogs & derivatives,  pharmacology
Vascular Resistance / drug effects
Chemical
Reg. No./Substance:
0/Potassium Channel Blockers; 0/Potassium Channels; 0/Receptors, Purinergic P1; 10238-21-8/Glyburide; 56-65-5/Adenosine Triphosphate; 58-55-9/Theophylline; 961-45-5/8-phenyltheophylline

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


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