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Adenosine A3 pretreatment before cardioplegic arrest attenuates postischemic cardiac dysfunction
V H Thourani1, R S Ronson, J E Jordan
1Department of Surgery, Emory University School of Medicine, Atlanta, Georgia, USA.
The Annals of Thoracic Surgery
|July 3, 1999
Summary
Adenosine A3 receptor stimulation before ischemia protects heart function and reduces injury. However, it offers no benefit when used during cardioplegia.
Area of Science:
- Cardiology
- Pharmacology
- Physiology
Background:
- The cardioprotective effects of adenosine A3 receptors during cardioplegia are unknown.
- This study investigates the role of an adenosine A3 receptor agonist in reducing myocardial injury.
Purpose of the Study:
- To test if adenosine A3 receptor agonist Cl-IB-MECA, as pretreatment and/or cardioplegic additive, reduces postischemic myocardial injury.
- To evaluate the impact of adenosine A3 receptor stimulation on cardiac function and injury markers.
Main Methods:
- Isolated perfused rat hearts subjected to ischemia and hypothermic cardioplegia.
- Hearts were divided into four groups: control, A3 receptor agonist pretreatment, cardioplegic additive, or both.
- Cardiac function (left ventricular developed pressure) and injury markers (creatine kinase, tissue water) were assessed post-reperfusion.
Main Results:
- Adenosine A3 receptor pretreatment significantly improved left ventricular developed pressure post-reperfusion compared to control.
- Pretreatment and combined pretreatment/cardioplegia groups showed reduced creatine kinase release and myocardial edema.
- Using the agonist solely as a cardioplegic additive did not provide significant cardioprotection.
Conclusions:
- Adenosine A3 receptor stimulation as a pretreatment effectively attenuates postischemic cardiodynamic dysfunction and myocardial injury.
- Adenosine A3 receptor stimulation offers no cardioprotective benefit when used as an adjunct to cold cardioplegia.