title: 12-lipoxygenase in opioid-induced delayed cardioprotection: gene array, mass spectrometric, and pharmacological analyses.
abstract: 12-lipoxygenase (12-LO) has been shown to be a factor in acute ischemic preconditioning (IPC) in the isolated rat heart; however, no studies have been reported in delayed PC. We characterized the role of 12-LO in an intact rat model of delayed PC induced by a delta-opioid agonist SNC-121 (SNC). Rats were pretreated with SNC and allowed to recover for 24 hours. They were then treated with either baicalein or phenidone, 2 selective 12-LO inhibitors. In addition, SNC-pretreated rats had plasma samples isolated at different times after ischemia-reperfusion for liquid chromatographic-mass spectrometric analysis of the major metabolic product of 12-LO, 12-HETE. Similar studies were conducted with inhibitors. Gene array data showed a significant induction of 12-LO message (P<0.05) after opioid pretreatment. This induction in 12-LO mRNA was confirmed by real-time polymerase chain reaction, and 12-LO protein expression was enhanced by SNC pretreatment at 24 hours relative to vehicle treatment. Both baicalein and phenidone attenuated the protective effects of SNC pretreatment on infarct size (50+/-4% and 42+/-3% versus 29+/-2%, P<0.05, respectively). No significant differences were observed in 12-HETE concentrations between baseline control and SNC-treated rats. However, 12-HETE concentrations were increased significantly at both 15 minutes during ischemia and at 1 hour of reperfusion in the SNC-treated rats compared with controls. Baicalein and phenidone attenuated the increase in 12-HETE at 1 hour of reperfusion. These data suggest that SNC-121 appears to enhance message and subsequently the activity and expression of 12-LO protein during times of stress, resulting in delayed cardioprotection.
authors.affiliation: Medical College of Wisconsin, Department of Pharmacology and Toxicology, 8701 Watertown Plank Rd, Milwaukee, WI 53226, USA.
authors.forename: Hemal H
authors.initials: HH
authors.lastname: Patel
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Fryer
authors.forename: Eric R
authors.initials: ER
authors.lastname: Gross
authors.forename: Richard A
authors.initials: RA
authors.lastname: Bundey
authors.forename: Anna K
authors.initials: AK
authors.lastname: Hsu
authors.forename: Marilyn
authors.initials: M
authors.lastname: Isbell
authors.forename: Leonard O V
authors.initials: LO
authors.lastname: Eusebi
authors.forename: Roderick V
authors.initials: RV
authors.lastname: Jensen
authors.forename: Steven R
authors.initials: SR
authors.lastname: Gullans
authors.forename: Paul A
authors.initials: PA
authors.lastname: Insel
authors.forename: Kasem
authors.initials: K
authors.lastname: Nithipatikom
authors.forename: Garrett J
authors.initials: GJ
authors.lastname: Gross
mesh_terms: D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid / Q000096:biosynthesis; D000818:Animals; D001092:Arachidonate 12-Lipoxygenase / Q000235:genetics / Q000502:physiology*; D016718:Arachidonic Acid / Q000378:metabolism; D001549:Benzamides / Q000494:pharmacology*; D015153:Blotting, Western; D002316:Cardiotonic Agents / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D020869:Gene Expression Profiling; D006439:Hemodynamics / Q000187:drug effects; D019157:Ischemic Preconditioning, Myocardial; D007700:Kinetics; D016859:Lipoxygenase Inhibitors; D008297:Male; D015428:Myocardial Reperfusion Injury / Q000201:enzymology / Q000235:genetics / Q000378:metabolism / Q000517:prevention & control*; D009206:Myocardium / Q000201:enzymology; D020411:Oligonucleotide Array Sequence Analysis; D010879:Piperazines / Q000494:pharmacology*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D017465:Receptors, Opioid, delta / Q000819:agonists*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D001549:Benzamides; D002316:Cardiotonic Agents; D004791:Enzyme Inhibitors; D016859:Lipoxygenase Inhibitors; D010879:Piperazines; D012333:RNA, Messenger; D017465:Receptors, Opioid, delta; C102990:SNC 121; D016718:Arachidonic Acid; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D001092:Arachidonate 12-Lipoxygenase