TY - JOUR T1 - Role of Nitric-Oxide Synthase, Free Radicals, and Protein Kinase C δ in Opioid-Induced Cardioprotection JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 1012 LP - 1019 DO - 10.1124/jpet.301.3.1012 VL - 301 IS - 3 AU - Hong Yan Zhang AU - Bradley C. McPherson AU - Huiping Liu AU - Timir Baman AU - Steven S. McPherson AU - Peter Rock AU - Zhenhai Yao Y1 - 2002/06/01 UR - http://jpet.aspetjournals.org/content/301/3/1012.abstract N2 - Opioids generate free radicals that mediate protection in isolated cultured cardiomyocytes. We hypothesize that the nature of these radicals is nitric oxide, and that nitric oxide activates the protein kinase C (PKC) δ isoform. Through this signal transduction pathway, opiates protect cardiomyocytes during hypoxia and reoxygenation. Cell viability was quantified in chick embryonic ventricular myocytes with propidium iodide. Oxygen radicals were quantified using a molecular probe, 2′,7′-dichlorofluorescin diacetate (DCFH-DA). After a 10-min infusion of the opioid δ receptor agonist BW373U86 (BW; 2 or 20 pM) and a 10-min drug-free period, cells were subjected to hypoxia for 1 h followed by reoxygenation for 3 h. BW produced a concentration-dependent reduction in cardiomyocyte death (2 pM, 35.3 ± 3.9%, n = 5; 20 pM, 21.5 ± 4.0%, n = 8, p < 0.05 versus controls) and attenuated oxidant stress compared with controls (43.3 ± 4.2%, n = 8). The increase in DCFH-DA oxidation with BW before hypoxia was abolished by the specific nitric-oxide synthase inhibitors nitro-l-arginine methyl ester (l-NAME) orNG-monomethyl-l-arginine (l-NMMA) (100 μM each). l-NAME orl-NMMA blocked the protective effects of BW. BW selectively increased the activity of PKC δ isoform in the particulate fraction, and its protection was abolished by the selective PKC δ inhibitor rottlerin (1 μM). Similar to BW, infusion with 5 μM of the nitric oxide donorS-nitroso-N-acetylpenicillamine (SNAP) reduced cardiomyocyte death (24.6 ± 3.7, n = 8), and this protection was blocked by chelerythrine or rottlerin. Chelerythrine and rottlerin had no effect on BW-generated oxygen radicals before hypoxia, but they abolished the protection of SNAP. The nature of DCFH oxidation produced by opioid δ receptor stimulation is nitric oxide. Nitric oxide mediates cardioprotection via activating PKC δ in isolated myocytes. The American Society for Pharmacology and Experimental Therapeutics ER -