The role of peroxynitrite in hypoxia-reoxygenation-induced coronary vasospasm was investigated in isolated bovine coronary arteries. Hypoxia-reoxygenation selectively blunted prostacyclin (PGI2)-dependent vasorelaxation and elicited a sustained vasoconstriction that was blocked by a cyclooxygenase inhibitor, indomethacin, and SQ29548, a thromboxane (Tx)A2/prostaglandin H2 receptor antagonist, b...

The primary pharmacological target of acetaminophen is prostaglandin endoperoxide H2 synthase (PGHS). The enzymatic catalytic mechanism is radical-based, initiated, and maintained by the persistent presence of peroxides, particularly peroxynitrite, which is termed "peroxide tone". Whereas the prevailing concept assumes a direct reduction of the active, oxidized enzyme by acetaminophen, here we ...

Reduced brain metabolism is an invariant feature of Alzheimer Disease (AD) that is highly correlated to the decline in brain functions. Decreased activities of key tricarboxylic acid cycle (TCA) cycle enzymes may underlie this abnormality and are highly correlated to the clinical state of the patient. The activity of the α-ketoglutarate dehydrogenase complex (KGDHC), an arguably rate-limiting e...

Inflammatory processes in chronic rejection remain a serious clinical problem in organ transplantation. Activated cellular infiltrate produces high levels of both superoxide and nitric oxide. These reactive oxygen species interact to form peroxynitrite, a potent oxidant that can modify proteins to form 3-nitrotyrosine. We identified enhanced immunostaining for nitrotyrosine localized to tubular...

Increasing evidence suggests that oxidative damage to proteins and other macromolecules is a salient feature of the pathology of Alzheimer's disease. Establishing the source of oxidants is key to understanding what role they play in the pathogenesis of Alzheimer's disease, and one way to examine this issue is to determine which oxidants are involved in damage. In this study, we examine whether ...

Astaxanthin captured peroxynitrite to form nitroastaxanthins. 15-Nitroastaxanthin was a major reaction product of astaxanthin with peroxynitrite. Here, the anti-oxidative, anti-tumor-promoting, and anti-carcinogensis activities of 15-nitroastaxanthin were investigated. In addition to astaxanthin, 15-nitroastaxanthin showed excellent singlet oxygen quenching activity. Furthermore, 15-nitroastaxa...

In recent years, much interest has been generated by the idea that nitrosative stress plays a role in aetiology of human diseases, such as atherosclerosis, inflammation, cancer, and neurological diseases. The chemical changes mediated reactive nitrogen species (RNS) are detrimental to cell function, because they can cause nitration, which alter structures cellular proteins, DNA, lipids, hence, ...

BACKGROUND Peroxynitrite, a product of the reaction of superoxide with nitric oxide, causes oxidative stress with concomitant inactivation of enzymes, poly(ADP-ribosylation), mitochondrial dysfunction and impaired stress signalling, as well as protein nitration. In this study, we sought to determine the effect of preventing protein nitration or increasing peroxynitrite decomposition on diabetic...

Peroxynitrite as one crucial metabolite of NO-derived agents has been well multi-investigated to inspect its potential role and sought to define its concrete mechanism underlying the memory loss and impaired cognition involved in pathological processes. In this investigation, the cell viability was assessed by the MTT assay. The neurotoxicity of peroxynitrite was analyzed by using immunohistoch...