sb-415286 and Myocardial-Infarction

Pharmacological treatment of reperfusion injury using insulin and GSK3β inhibition has been shown to be cardioprotective, however, their interaction with the endogenous cardioprotective strategy, ischemic postconditioning, is not known.. Langendorff perfused ex vivo rat hearts were subjected to 30 min of regional ischemia and 120 min of reperfusion. For the first 15 min of reperfusion hearts received either vehicle (Ctr), insulin (Ins) or a GSK3β inhibitor (SB415286; SB41), with or without interruption of ischemic postconditioning (IPost; 3 × 30 s of global ischemia). In addition, the combination of insulin and SB41 for 15 min was assessed.. Insulin, SB41 or IPost significantly reduced infarct size versus vehicle treated controls (IPost 33.5 ± 3.3%, Ins 33.5 ± 3.4%, SB41 30.5 ± 3.0% vs. Ctr 54.7 ± 6.8%, p < 0.01). Combining insulin and SB415286 did not confer additional cardioprotection compared to the treatments given alone (SB41. Pharmacological reperfusion treatment with insulin and SB41 interferes with the cardioprotection afforded by ischemic postconditioning.

Topics: Aminophenols; Animals; Disease Models, Animal; Glycogen Synthase Kinase 3 beta; Insulin; Ischemic Postconditioning; Isolated Heart Preparation; Male; Maleimides; Myocardial Infarction; Myocardial Reperfusion Injury; Myocardium; Phosphorylation; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Rats, Wistar; Signal Transduction; STAT3 Transcription Factor

Glycogen synthase kinase (GSK) inhibition produced by ischemic preconditioning has been previously shown to be regulated through phosphatidylinositol-3 kinase (PI3K). Therefore, we determined whether opioid-induced cardioprotection (OIC) occurs during reperfusion by altering GSK phosphorylation through PI3K and target of rapamycin (TOR). Furthermore, we determined if selective GSK inhibitors, SB216763(SB21) or SB415286(SB41), emulate OIC. Rats were treated with the nonselective opioid agonist, morphine (MOR, 0.3 mg/kg), the delta-selective opioid agonist BW373U86 (BW, 1 mg/kg), or the GSK inhibitors, SB21 (0.6 mg/kg) or SB41(1.0 mg/kg), either 10 minutes before ischemia or 5 minutes before reperfusion. Five minutes before opioid or SB21 treatment, some rats received either the PI3K inhibitor wortmannin (15 microg/kg) or LY294002 (0.3 mg/kg) or the TOR inhibitor rapamycin (3 microg/kg). After 30 minutes of ischemia followed by 2 hours of reperfusion, infarct size was assessed. MOR, BW, SB41, and SB21 reduced infarct size compared with vehicle when administered before ischemia (42.9+/-2.6, 40.3+/-2.3, 46.6+/-1.6, 42.2+/-1.8 versus 60.0+/-1.1%, respectively; P<0.001) and showed similar protection when administered 5 minutes before reperfusion (43.6+/-2.3, 40.2+/-2.6, 44.8+/-2.8, 39.4+/-0.8%, respectively; P<0.001). Wortmannin, LY294002, and rapamycin were found to inhibit OIC; however, they did not abrogate SB21-induced infarct size reduction. At 5 minutes of reperfusion, both MOR and BW increased P-GSKbeta at Ser9 in the ischemic zone compared with vehicle (181+/-20, 178+/-15 versus 75+/-17 DU, respectively; P<0.05), and this effect was abrogated by prior administration of wortmannin or rapamycin in MOR-treated rats. Furthermore, no differences were seen in phosphorylation of GSKalpha (Ser21 or Tyr279) or phosphorylation of GSKbeta (Tyr216). These data indicate that OIC occurs via the phosphorylation of GSKbeta at Ser9 during reperfusion.

Topics: Aminophenols; Androstadienes; Animals; Benzamides; Cardiotonic Agents; Chromones; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Indoles; Male; Maleimides; Morphine; Morpholines; Myocardial Infarction; Narcotic Antagonists; Nuclear Receptor Subfamily 1, Group F, Member 3; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Piperazines; Premedication; Rats; Rats, Sprague-Dawley; Receptors, Opioid, delta; Receptors, Retinoic Acid; Receptors, Thyroid Hormone; Signal Transduction; Sirolimus; Wortmannin