κ-Opioid Receptors Mediate Cardioprotection by Remote Preconditioning

Anesthetized male Sprague-Dawley rats subjected to myocardial ischemia-reperfusion (30 min left anterior descending coronary artery ligation followed by 120 min reperfusion) and isolated ventricular myocytes.

Remote preconditioning (3 cycles of 5 min right femoral artery occlusion followed by 5 min reperfusion) or U-50,488H (10 mg/kg intravenous, a kappa-opioid receptor agonist).

Ischemia-reperfusion alone, or co-treatment with nor-binaltorphimine (10 mg/kg intravenous, kappa-opioid receptor antagonist), atractyloside (5 mg/kg intravenous, mitochondrial permeability transition pore activator), or naltrindole (5 mg/kg, delta-opioid receptor antagonist).

Infarct size (determined by 2,3,5-triphenyltetrazolium chloride staining) and plasma lactate dehydrogenase level.surrogate