title: Essential activation of PKC-delta in opioid-initiated cardioprotection.
abstract: Stimulation of the delta(1)-opioid receptor confers cardioprotection to the ischemic myocardium. We examined the role of protein kinase C (PKC) after delta-opioid receptor stimulation with TAN-67 or D-Ala(2)-D-Leu(5)-enkephalin (DADLE) in a rat model of myocardial infarction induced by a 30-min coronary artery occlusion and 2-h reperfusion. Infarct size (IS) was determined by tetrazolium staining and expressed as a percentage of the area at risk (IS/AAR). Control animals, subjected to ischemia and reperfusion, had an IS/AAR of 59.9 +/- 1.8. DADLE and TAN-67 administered before ischemia significantly reduced IS/AAR (36.9 +/- 3.9 and 36.7 +/- 4.7, respectively). The delta(1)-selective opioid antagonist 7-benzylidenenaltrexone (BNTX) abolished TAN-67-induced cardioprotection (54.4 +/- 1.3). Treatment with the PKC antagonist chelerythrine completely abolished DADLE- (61.8 +/- 3.2) and TAN-67-induced cardioprotection (55.4 +/- 4.0). Similarly, the PKC antagonist GF 109203X completely abolished TAN-67-induced cardioprotection (54.6 +/- 6.6). Immunofluorescent staining with antibodies directed against specific PKC isoforms was performed in myocardial biopsies obtained after 15 min of treatment with saline, chelerythrine, BNTX, or TAN-67 and chelerythrine or BNTX in the presence of TAN-67. TAN-67 induced the translocation of PKC-alpha to the sarcolemma, PKC-beta(1) to the nucleus, PKC-delta to the mitochondria, and PKC-epsilon to the intercalated disk and mitochondria. PKC translocation was abolished by chelerythrine and BNTX in TAN-67-treated rats. To more closely examine the role of these isoforms in cardioprotection, we utilized the PKC-delta selective antagonist rottlerin. Rottlerin abolished opioid-induced cardioprotection (48.9 +/- 4.8) and PKC-delta translocation without affecting the translocation of PKC-alpha, -beta(1), or -epsilon. These results suggest that PKC-delta is a key second messenger in the cardioprotective effects of delta(1)-opioid receptor stimulation in rats.
authors.affiliation: Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
authors.forename: R M
authors.initials: RM
authors.lastname: Fryer
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: A K
authors.initials: AK
authors.lastname: Hsu
authors.forename: G J
authors.initials: GJ
authors.lastname: Gross
mesh_terms: D000098:Acetophenones / Q000494:pharmacology; D000470:Alkaloids; D000700:Analgesics / Q000494:pharmacology; D000818:Animals; D053119:Benzophenanthridines; D001578:Benzopyrans / Q000494:pharmacology; D001597:Benzylidene Compounds / Q000494:pharmacology; D016308:Enkephalin, Leucine-2-Alanine / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006339:Heart Rate; D007211:Indoles / Q000494:pharmacology; D019157:Ischemic Preconditioning, Myocardial; D007527:Isoenzymes / Q000378:metabolism*; D008297:Male; D008301:Maleimides / Q000494:pharmacology; D009203:Myocardial Infarction / Q000188:drug therapy / Q000378:metabolism; D017202:Myocardial Ischemia / Q000188:drug therapy* / Q000378:metabolism*; D015428:Myocardial Reperfusion Injury / Q000188:drug therapy / Q000378:metabolism; D009206:Myocardium / Q000201:enzymology; D009271:Naltrexone / Q000031:analogs & derivatives* / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D010617:Phenanthridines / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism*; D051745:Protein Kinase C-delta; D011804:Quinolines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D017465:Receptors, Opioid, delta / Q000819:agonists / Q000037:antagonists & inhibitors
chemical_list: D000098:Acetophenones; D000470:Alkaloids; D000700:Analgesics; D053119:Benzophenanthridines; D001578:Benzopyrans; D001597:Benzylidene Compounds; D004791:Enzyme Inhibitors; D007211:Indoles; D007527:Isoenzymes; D008301:Maleimides; D009292:Narcotic Antagonists; D010617:Phenanthridines; D011804:Quinolines; D017465:Receptors, Opioid, delta; C094142:TAN 67; C077358:7-benzylidenenaltrexone; D009271:Naltrexone; D016308:Enkephalin, Leucine-2-Alanine; C085746:rottlerin; C016299:chelerythrine; C497260:Prkcd protein, rat; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; C070515:bisindolylmaleimide I