title: Morphine mimics the antiapoptotic effect of preconditioning via an Ins(1,4,5)P3 signaling pathway in rat ventricular myocytes.
abstract: Morphine has cardioprotective effects against ischemic-reperfusion injuries. This study investigates whether morphine could mimic the antiapoptotic effect of preconditioning using a model of cultured neonatal rat cardiomyocytes subjected to metabolic inhibition (MI). To quantify MI-induced apoptosis, DNA fragmentation and mitochondrial cytochrome c release levels were measured by ELISA. MI-dependent DNA fragmentation was prevented by both Z-VAD-fmk (20 microM), a pan-caspase inhibitor, and cyclosporine A (CsA; 5 microM), a mitochondrial pore transition blocker, added during MI (36% and 54% decrease, respectively). MI-dependent cytochrome c release was not blocked by Z-VAD-fmk but was decreased (38%) by CsA during MI. Metabolic preconditioning (MIP) and preconditioning with morphine (1 microM) were also assessed. MI-dependent DNA fragmentation and cytochrome c release were prevented by MIP (40% and 45% decrease, respectively) and morphine (34% and 45%, respectively). The antiapoptotic effect of morphine was abolished by naloxone (10 nM), a nonselective opioid receptor antagonist, or xestospongin C (XeC, 400 nM), an inhibitor of inositol (1,4,5)-trisphosphate [Ins(1,4,5)P(3)]-mediated Ca(2+) release. Ca(2+) preconditioning, induced by increasing extracellular Ca(2+) from 1.8 to 3.3 mM, mimicked the antiapoptotic effect of morphine on DNA fragmentation (24% decrease) and cytochrome c release (57% decrease). This effect mediated by extracellular Ca(2+) was also abolished by XeC. Measurements of intracellular Ca(2+) concentration using fura-2 microspectrofluorimetry showed that morphine induces Ins(1,4,5)P(3)-dependent Ca(2+) transients abolished by 2-aminoethoxydiphenyl borate (2-APB), a cell-permeable Ins(1,4,5)P(3) antagonist. These results suggest that morphine preconditioning prevents simulated ischemia-reperfusion-induced apoptosis via an Ins(1,4,5)P(3) signaling pathway in rat ventricular myocytes.
authors.affiliation: Laboratoire de Génomique Fonctionnelle, Centre National de la Recherche Scientifique, Montpellier Cedex 5, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Barrère-Lemaire
authors.forename: Nicolas
authors.initials: N
authors.lastname: Combes
authors.forename: Catherine
authors.initials: C
authors.lastname: Sportouch-Dukhan
authors.forename: Sylvain
authors.initials: S
authors.lastname: Richard
authors.forename: Joël
authors.initials: J
authors.lastname: Nargeot
authors.forename: Christophe
authors.initials: C
authors.lastname: Piot
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D019610:Cytoprotection / Q000502:physiology; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism*; D007425:Intracellular Membranes / Q000378:metabolism; D019157:Ischemic Preconditioning, Myocardial; D009020:Morphine / Q000494:pharmacology*; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D009294:Narcotics / Q000494:pharmacology*; D051381:Rats; D011921:Rats, Inbred WKY; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D009294:Narcotics; D009020:Morphine; D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium