Pretreatment with Endothelin-1 Mimics Ischemic Preconditioning Against Infarction in Isolated Rabbit Heart

We have proposed that ischemic preconditioning in rabbit hearts is initiated by adenosine receptor stimulation resulting in activation of protein kinase C. If this theory is correct then any agonist which can activate PKC should also put the heart into a preconditioned state. This study sought to determine whether endothelin-1 (ET-1), which is known to activate protein kinase C, can also mimic ischemic preconditioning. Isolated rabbit hearts experienced 30 min of regional ischemia followed by 120 min of reperfusion. Infarct size was measured with triphenyltetrazolium chloride. In control hearts infarction was 30.3±2.5% of the risk zone. Preconditioning with 5 min global ischemia and 10 min reperfusion reduced infarct size to 5.6±0.7% ( P