caa a22 4500 477120164 CHVBK 20180405111634.0 cr unu---uuuuu 170330e19960401xx s 000 0 eng 10.1007/BF00227902 doi (NATIONALLICENCE)springer-10.1007/BF00227902 Alpha-tocopherol pretreatment improves endothelium-dependent vasodilation in aortic strips of young and aging rats exposed to oxidative stress [Elektronische Daten] [Carlo Guarnieri, Emanuele Giordano, Claudio Muscari, Loris Grossi, Claudio Caldarera] Acetylcholine-induced, endothelium-dependent relaxation of norepinephrine-precontracted aortic strips, was severely impaired after exposure to a hypoxanthine/xanthine oxidase reaction generating oxygen radicals. This effect was more evident in aortic strips of aging rats (24 months old) in comparison to young rats (3 months old). The addition of authentic ·NO (1 μM) completely relaxed aortic strips exposed to oxidative stress both in young and aging rats. In vitro EPR measurements showed that the ·NO signal was reduced by enzymatic O2-generating reaction. The activity of a partial purified preparation of constitutive NO synthase from rat cerebellum was significantly decreased after exposure to exogenous oxygen radicals. Pretreatment of aortic strips with 100 μM alpha-tocopherol-phosphate, produced a significant improvement of acetylcholine-dependent relaxation in the aortic strips exposed to oxidative stress, particularly in the aged vessel. The content of malondialdehyde in aortic tissue did not change after oxidative stress or alpha-tocopherol pretreatment. Alpha-tocopherol was unable to recover the NO synthase activity depressed in vitro by hypoxanthine/xanthine oxidase reaction. This study confirms that an oxidative stress impairs the endothelium-mediated vasodilation. Alpha-tocopherol pretreatment protects the vessel against this damage. The mechanism of action of alpha-tocopherol is unknown, but seems unrelated to an antioxidant activity. Kluwer Academic Publishers, 1996 nitric oxide nationallicence oxygen radicals nationallicence tocopherol nationallicence vasodilation nationallicence aging rat nationallicence ACh : acethylcholine nationallicence EPR : electron paramagnetic resonance nationallicence ROS : reactive oxygen species nationallicence MDA : malondialdehyde nationallicence NE : norepinephrine nationallicence cNOS : constitutive nitric oxide synthase nationallicence Guarnieri Carlo Department of Biochemistry ‘G. Moruzzi', Centre of Research on Heart Metabolism, University of Bologna, v.Irnerio 48, 40126, Bologna, Italy aut Giordano Emanuele Department of Biochemistry ‘G. Moruzzi', Centre of Research on Heart Metabolism, University of Bologna, v.Irnerio 48, 40126, Bologna, Italy aut Muscari Claudio Department of Biochemistry ‘G. Moruzzi', Centre of Research on Heart Metabolism, University of Bologna, v.Irnerio 48, 40126, Bologna, Italy aut Grossi Loris Department of Organic Chemistry, University of Bologna, Italy aut Caldarera Claudio Department of Biochemistry ‘G. Moruzzi', Centre of Research on Heart Metabolism, University of Bologna, v.Irnerio 48, 40126, Bologna, Italy aut Molecular and Cellular Biochemistry Kluwer Academic Publishers 157/1-2(1996-04-01), 223-228 0300-8177 157:1-2<223 1996 157 11010 https://doi.org/10.1007/BF00227902 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00227902 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Guarnieri Carlo Department of Biochemistry ‘G. Moruzzi', Centre of Research on Heart Metabolism, University of Bologna, v.Irnerio 48, 40126, Bologna, Italy aut NATIONALLICENCE 700 1- Giordano Emanuele Department of Biochemistry ‘G. Moruzzi', Centre of Research on Heart Metabolism, University of Bologna, v.Irnerio 48, 40126, Bologna, Italy aut NATIONALLICENCE 700 1- Muscari Claudio Department of Biochemistry ‘G. Moruzzi', Centre of Research on Heart Metabolism, University of Bologna, v.Irnerio 48, 40126, Bologna, Italy aut NATIONALLICENCE 700 1- Grossi Loris Department of Organic Chemistry, University of Bologna, Italy aut NATIONALLICENCE 700 1- Caldarera Claudio Department of Biochemistry ‘G. Moruzzi', Centre of Research on Heart Metabolism, University of Bologna, v.Irnerio 48, 40126, Bologna, Italy aut NATIONALLICENCE 773 0- Molecular and Cellular Biochemistry Kluwer Academic Publishers 157/1-2(1996-04-01), 223-228 0300-8177 157:1-2<223 1996 157 11010 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer