title: Effects of various oxidants and antioxidants on the p38-MAPK signalling pathway in the perfused amphibian heart.
abstract: We investigated the effects of different antioxidants such as L-ascorbic acid, catalase, and superoxide dismutase (SOD), on the p38-MAPK activation induced by oxidative stress in the isolated perfused amphibian heart. Oxidative stress was exemplified by perfusing hearts with 30 microM H(2)O(2) for 5 min or with the enzymatic system of xanthine/xanthine oxidase (200 microM/10 mU/ml, respectively) for 10 min. H(2)O(2)-induced activation of p38-MAPK (7.04 +/- 0.20-fold relative to control values) was totally attenuated by L-ascorbic acid (100 microM) or catalase (150 U/ml). These results were confirmed by immunohistochemical studies in which the phosphorylated form of p38-MAPK was localised in the perinuclear region and dispersedly in the cytoplasm of the ventricular cells during H(2)O(2) treatment, a pattern that was abolished by catalase or L-ascorbic acid. p38-MAPK was also activated (2.34 +/- 0.17-fold) by perfusing amphibian hearts with the reactive oxygen species (ROS)-generating system of xanthine/xanthine oxidase and this activation sustained in the presence of 150 U/ml catalase (2.16 +/- 0.26-fold), 50 U/ml SOD (2.02 +/- 0.07) or 100 microM L-ascorbic acid (2.18 +/- 0.10), but was suppressed by the combination of 150 U/ml catalase and 50 U/ml SOD. Finally, our studies showed that xanthine/xanthine oxidase induced the phosphorylation of the potent p38-MAPK substrates MAPKAPK2 (3.14 +/- 0.27-fold) and HSP27 (5.32 +/- 0.83-fold), which are implicated in cell protection, and this activation was reduced by the simultaneous use of catalase and SOD.
authors.affiliation: Department of Animal & Human Physiology, School of Biology, Faculty of Sciences, University of Athens, Panepistimioupolis, Athens, 157 84, Greece.
authors.forename: Catherine
authors.initials: C
authors.lastname: Gaitanaki
authors.forename: Maria
authors.initials: M
authors.lastname: Papatriantafyllou
authors.forename: Konstantina
authors.initials: K
authors.lastname: Stathopoulou
authors.forename: Isidoros
authors.initials: I
authors.lastname: Beis
mesh_terms: D000663:Amphibians; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000494:pharmacology; D002374:Catalase / Q000494:pharmacology; D006321:Heart / Q000187:drug effects*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D009206:Myocardium / Q000201:enzymology / Q000378:metabolism*; D016877:Oxidants / Q000494:pharmacology*; D010477:Perfusion; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D019820:Xanthine / Q000378:metabolism; D014969:Xanthine Oxidase / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*; D000099190:MAP-Kinase-Activated Kinase 2
chemical_list: D000975:Antioxidants; D001205:Ascorbic Acid; D002374:Catalase; D006861:Hydrogen Peroxide; D047908:Intracellular Signaling Peptides and Proteins; D016877:Oxidants; D017346:Protein Serine-Threonine Kinases; D019820:Xanthine; D014969:Xanthine Oxidase; D048051:p38 Mitogen-Activated Protein Kinases; D000099190:MAP-Kinase-Activated Kinase 2