Document Detail

Activation of ATP-sensitive potassium channels lowers threshold for ischemic preconditioning in dogs.
MedLine Citation:
PMID:  7977819     Owner:  NLM     Status:  MEDLINE    
The purpose of the present study was to determine whether enhanced activation of myocardial ATP-dependent potassium channels (KATP) with a potassium channel opener, bimakalim, can reduce the time necessary to produce the protective effect of ischemic preconditioning and to determine whether this effect is mediated via accelerating the rate of action potential shortening during preconditioning. Barbital-anesthetized dogs were subjected to 60 min of left anterior descending coronary artery (LAD) occlusion followed by 4 h of reperfusion. Ten minutes of preconditioning was found to markedly reduce myocardial infarct size from 30.6 +/- 4.7 to 7.1 +/- 2.6%. Subsequently, it was observed that either 3 min of LAD occlusion or a 3-min intracoronary infusion with 0.3 micrograms/min of bimakalim did not reduce myocardial infarct size. However, intracoronary infusion with bimakalim during the 3-min preconditioning period markedly reduced myocardial infarct size to a similar extent as that of ischemic preconditioning (12.2 +/- 1.9%). In addition, it was observed that bimakalim markedly accelerated the ischemia-induced shortening of the action potential during preconditioning. These results are the first to demonstrate that activation of KATP channels with a potassium channel opener reduces the threshold of time necessary to produce preconditioning in anesthetized dogs. These data also suggest that KATP channel activation may produce this effect by enhancing the rate of ischemic myocardial action potential shortening during preconditioning.
Z Yao; G J Gross
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  267     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1994 Nov 
Date Detail:
Created Date:  1994-12-08     Completed Date:  1994-12-08     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H1888-94     Citation Subset:  IM    
Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee 53226.
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MeSH Terms
Action Potentials / drug effects
Adenosine Triphosphate / physiology*
Benzopyrans / pharmacology*
Blood Pressure / drug effects
Coronary Circulation / drug effects
Coronary Vessels / physiology,  physiopathology
Dihydropyridines / pharmacology*
Heart Rate / drug effects
Myocardial Infarction / physiopathology*
Myocardial Ischemia / physiopathology*
Myocardial Reperfusion*
Potassium Channels / physiology*
Time Factors
Vasodilator Agents / pharmacology*
Grant Support
Reg. No./Substance:
0/Benzopyrans; 0/Dihydropyridines; 0/Potassium Channels; 0/Vasodilator Agents; 117545-11-6/bimakalim; 56-65-5/Adenosine Triphosphate

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

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