Activation of ATP-sensitive potassium channels lowers threshold for ischemic preconditioning in dogs
| Autor: | Zhenhai Yao, G J Gross |
|---|---|
| Rok vydání: | 1994 |
| Předmět: |
Male
Dihydropyridines medicine.medical_specialty Potassium Channels Time Factors Physiology Vasodilator Agents Myocardial Infarction Myocardial Ischemia Action Potentials Blood Pressure Myocardial Reperfusion Anterior Descending Coronary Artery Adenosine Triphosphate Dogs Heart Rate Katp channels Coronary Circulation Physiology (medical) Internal medicine Occlusion medicine Animals Benzopyrans Myocardial infarction business.industry Cardiac action potential medicine.disease Coronary Vessels Potassium channel Cardiology Ischemic preconditioning Female Potassium channel opener Cardiology and Cardiovascular Medicine business |
| Zdroj: | American Journal of Physiology-Heart and Circulatory Physiology. 267:H1888-H1894 |
| ISSN: | 1522-1539 0363-6135 |
| DOI: | 10.1152/ajpheart.1994.267.5.h1888 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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