Document Detail

Sex-specific and exercise-acquired cardioprotection is abolished by sarcolemmal KATP channel blockade in the rat heart.
MedLine Citation:
PMID:  17237239     Owner:  NLM     Status:  MEDLINE    
The present study was conducted to determine whether the infarct sparing effect of short-term exercise is dependent on the operation of the myocardial sarcolemmal ATP-sensitive K(+) (K(ATP)) channel. Adult male and female Sprague-Dawley rats were exercised on a motorized treadmill for 5 days. Twenty-four hours following the training or sedentary period, hearts were isolated and exposed to 1 h of regional ischemia followed by 2 h of reperfusion on a modified Langendorf apparatus in the presence or absence of the sarcolemmal K(ATP) channel antagonist HMR-1098 (30 microM). Following the ischemia-reperfusion protocol, infarct size was determined as a percentage of the total ischemic zone at risk (ZAR). Short-term exercise reduced infarct size by 24% in males (32 +/- 2% of ZAR; P < 0.01) and by 18% in females (26 +/- 2% of ZAR; P < 0.05). Sarcolemmal K(ATP) channel blockade abolished the training-induced cardioprotection in both males and females, increasing infarct size to 43 +/- 3% and 52 +/- 4% of ZAR, respectively. In the absence of HMR-1098, infarct size was significantly lower in sedentary females than in males (33 +/- 4% vs. 42 +/- 2% of ZAR, respectively; P < 0.01). However, the presence of HMR-1098 abolished this sex difference, increasing infarct size by 58% in the sedentary females (P < 0.01) but having no effect on infarct size in sedentary males. This study demonstrates that the sex-specific and exercise-acquired resistance to myocardial ischemia-reperfusion injury is dependent on sarcolemmal K(ATP) activity during ischemia.
Adam J Chicco; Micah S Johnson; Casey J Armstrong; Joshua M Lynch; Ryan T Gardner; Geoff S Fasen; Cody P Gillenwater; Russell L Moore
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2007-01-19
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  292     ISSN:  0363-6135     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2007 May 
Date Detail:
Created Date:  2007-05-09     Completed Date:  2007-06-27     Revised Date:  2007-12-03    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H2432-7     Citation Subset:  IM    
Department of Integrative Physiology, University of Colorado at Boulder, Boulder, CO 80309, USA.
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MeSH Terms
Benzamides / pharmacology*
Exercise Therapy / methods*
Heart / drug effects,  physiopathology*
Myocardial Reperfusion Injury / physiopathology*,  therapy*
Physical Conditioning, Animal / methods*
Potassium Channels / drug effects,  metabolism*
Rats, Sprague-Dawley
Sex Factors
Treatment Outcome
Grant Support
Reg. No./Substance:
0/Benzamides; 0/HMR 1098; 0/Potassium Channels; 0/mitochondrial K(ATP) channel

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