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Tyrosine nitration in blood vessels occurs with increasing nitric oxide concentration
Author(s) -
Amirmansour Charles,
Vallance Patrick,
Bogle Richard G
Publication year - 1999
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1038/sj.bjp.0702590
Subject(s) - peroxynitrite , sodium nitroprusside , chemistry , nitration , nitric oxide , incubation , nitrotyrosine , superoxide , superoxide dismutase , biochemistry , hydroxocobalamin , nitrosylation , nitric oxide synthase , endocrinology , oxidative stress , biology , enzyme , vitamin b12 , organic chemistry , cyanocobalamin
Experiments were designed to explore the effects of nitric oxide (NO) donors on generation of superoxide (O 2 .− ) and peroxynitrite (ONOO − ) in rabbit aortic rings. Following inhibition of endogenous superoxide dismutase (SOD), significant basal release of O 2 .− was revealed (0.9±0.01×10 −12 mol min −1 mg −1 tissue). Generation of O 2 .− increased in a concentration‐dependent manner in response to NADH or NADPH (EC 50 =2.34±1.18×10 −4 and 6.21±1.79×10 −3 M respectively, n =4). NADH‐stimulated O 2 .− chemiluminescence was reduced by approximately 85% in the presence of exogenous SOD (15×10 3 U ml −1 ). Incubation of aortic rings with S‐nitrosoglutathione (GSNO; 1×10 −5 –3×10 −3 M ) or sodium nitroprusside (SNP; 1×10 −8 –1×10 −3 M ), resulted in a concentration‐dependent quenching of O 2 .− chemiluminescence which was proportional to NO release. ONOO − formation was assessed indirectly by determining protein tyrosine nitration in rabbit aorta using a specific antibody against nitrotyrosine. Basally and in the presence of NADH, a single band was detected. Incubation of aortic rings with either GSNO (1×10 −3 M ) alone or GSNO with NADH resulted in the appearance of additional nitrotyrosine bands. Incubation of serum albumin with GSNO alone did not cause nitrotyrosine formation. In contrast, incubation with 3‐morpholinosydonomine (SIN‐1; 1×10 −3 M , 10 min), resulted in marked nitration of albumin which was reduced by oxyhaemoglobin or SOD. Incubation of albumin with GSNO and pyrogallol, a O 2 .− generator, also resulted in protein nitration. Addition of exogenous NO results in nitrotyrosine formation in rabbit aortic rings. Nitrotyrosine formation is likely to result from the reaction of exogenous NO and basal endogenous O 2 .− resulting in the formation of ONOO − . Formation of ONOO − and nitration of tyrosine residues potentially could lead to vascular damage and might represent unexpected adverse effects of long‐term nitrate therapy.British Journal of Pharmacology (1999) 127 , 788–794; doi: 10.1038/sj.bjp.0702590