title: SCH 79797, a selective PAR1 antagonist, limits myocardial ischemia/reperfusion injury in rat hearts.
abstract: Myocardial ischemia/reperfusion (I/R) injury is partly mediated by thrombin. In support, the functional inhibition of thrombin has been shown to decrease infarct size after I/R. Several cellular responses to thrombin are mediated by a G-protein coupled protease-activated receptor 1 (PAR1).However, the role of PAR1 in myocardial I/R injury has not been well characterized. Therefore, we hypothesized that PAR1 inhibition will reduce the amount of myocardial I/R injury. After we detected the presence of PAR1 mRNA and protein in the rat heart by RT-PCR and immunoblot analysis,we assessed the potential protective role of SCH 79797, a selective PAR1 antagonist, in two rat models of myocardial I/R injury. SCH 79797 treatment immediately before or during ischemia reduced myocardial necrosis following I/R in the intact rat heart. This response was dose-dependent with the optimal dose being 25 microg/kg IV. Likewise, SCH 79797 treatment before ischemia in the isolated heart model reduced infarct size and increased ventricular recovery following I/R in the isolated heart model with an optimal concentration of 1 microM. This reduction was abolished by a PAR1 selective agonist. SCH 79797-induced resistance to myocardial ischemia was abolished by wortmannin, an inhibitor of PI3 kinase; L-NMA, a NOS inhibitor; and glibenclamide, a nonselective K(ATP) channel blocker. PAR1 activating peptide,wortmannin, L-NMA and glibenclamide alone had no effect on functional recovery or infarct size. A single treatment of SCH 79797 administered prior to or during ischemia confers immediate cardioprotection suggesting a potential therapeutic role of PAR1 antagonist in the treatment of injury resulting from myocardial ischemia and reperfusion.
authors.affiliation: Division of Cardiovascular Medicine, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226, USA. jstrande@mcw.edu
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Strande
authors.forename: Anna
authors.initials: A
authors.lastname: Hsu
authors.forename: Jidong
authors.initials: J
authors.lastname: Su
authors.forename: Xiangping
authors.initials: X
authors.lastname: Fu
authors.forename: Garrett J
authors.initials: GJ
authors.lastname: Gross
authors.forename: John E
authors.initials: JE
authors.lastname: Baker
mesh_terms: D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D002316:Cardiotonic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005905:Glyburide / Q000494:pharmacology; D006629:Hirudins / Q000494:pharmacology; D008297:Male; D009203:Myocardial Infarction / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control*; D015428:Myocardial Reperfusion Injury / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control*; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000378:metabolism; D011758:Pyrroles / Q000494:pharmacology* / Q000627:therapeutic use; D011799:Quinazolines / Q000494:pharmacology* / Q000627:therapeutic use; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D044463:Receptor, PAR-1 / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D012107:Research Design; D015398:Signal Transduction / Q000187:drug effects*; D013917:Thrombin / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013997:Time Factors; D016277:Ventricular Function, Left / Q000187:drug effects; D000077191:Wortmannin; D019323:omega-N-Methylarginine / Q000494:pharmacology; D010975:Platelet Aggregation Inhibitors
chemical_list: D000730:Androstadienes; D002316:Cardiotonic Agents; D004791:Enzyme Inhibitors; D005905:Glyburide; D006629:Hirudins; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D009842:Oligopeptides; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D051057:Proto-Oncogene Proteins c-akt; D011758:Pyrroles; D011799:Quinazolines; D012333:RNA, Messenger; D044463:Receptor, PAR-1; D011994:Recombinant Proteins; D013917:Thrombin; D000077191:Wortmannin; D019323:omega-N-Methylarginine; D010975:Platelet Aggregation Inhibitors; C415424:N3-cyclopropyl-7-((4-(1-methylethyl)phenyl)methyl)-7H-pyrrolo(3, 2-f)quinazoline-1,3-diamine; C462999:PAR-1-activating peptide; C083544:lepirudin