Nitrogen species, reactive

Nitric oxide (NO) is synthesised by one of three isoforms of nitric oxide 

---

Carotenoid reactions with ROS or RNS (reactive nitrogen species) would generate prooxidative products. ... 

Brennan M-L and et al. (2002) A tale of two controversies. Defining both the role of peroxidases in nitrotyro-sine formation in vivo using eosinophil peroxidase and myeloperoxidase-deficient mice, and the natnre of the peroxidase-generated reactive nitrogen species. J Biol Chem 277 17415-17427. 

Figure 10.1 Ward cascade showing the cooperation between cytoprotective enzymes and antioxidants for scavenging of reactive oxygen and reactive nitrogen species.

Effects of Reactive Nitrogen Species on Prostaglandin H-Catalyzed Processes... 

It has already been mentioned earlier that similar to LOXs, prostaglandin H synthases can be activated or inhibited by reactive nitrogen species. Nitric oxide may exhibit the inhibitory [58,65,86,101 104] or stimulatory effects [105 110] on PGHSs. Inhibitory effects depend on the ability of nitric oxide to reduce the ferric enzyme to the inactive ferrous form, competition... 

Reactive nitrogen species are another factor of free radical damage in rheumatoid arthritis, although their role is less studied than that of oxygen radicals. Stichtenoth and Frolich [242] pointed out that the inhibition of nitric oxide synthesis had beneficial effects in humans. Mazzetti et al. [243] found that IL-1(3 stimulated NO production in RA chondrocytes. We demonstrated that NO synthase of RA neutrophils generated the enhanced amount of peroxynitrite [234]. Nitric oxide and oxygen radicals are also important inducers of death of human osteoarthritic synoviocytes [244]. 

The latest studies show that reactive nitrogen species play even more important role in asthma development. It was found that exhaled nitrogen oxide, an indicator of eosinophilic airway inflammation, is drastically enhanced in asthmatic patients. Correspondingly, it has been shown that lung damage is characterized by the augmentation of nitrotyrosine and iNOS expression in neutrophils, eosinophils, and macrophages in the airways of asthmatic patients [266],... 

Scheme 1.4 Oxidation and reduction of reactive nitrogen species.

H. Kaur, M.N. Hughes, C.J. Green, P. Naughton, R. Foresti and R. Motterlini, Interaction of bilirubin and biliverdin with reactive nitrogen species. FEBS Lett. 543 (2003) 113-119. 

Reactive oxygen species (ROS) are a common mediator of apoptosis. Induction of apoptosis by bile acids appears to be caused, at least in part, by oxidative stress and consequent DNA damage. Unrepaired DNA damage can trigger apoptosis. Table 3.3 lists studies indicating that bile acids induce production of ROS and reactive nitrogen species (RNS) in cells of the GI tract. Table 3.4... 

Deleterious protein cross-linking can also be induced by reactive nitrogen species (RNS) such as peroxynitrite ONOO formed by the reaction of superoxide with nitric oxide (NO). The cross-links are formed between tyrosine residues following nitration by peroxynitrite (Sitte, 2003). Carnosine appears to play roles not only in NO generation but also in protection against excess NO production by inducible nitric oxide synthetase (NOS), thereby preventing ONOO-mediated protein modification (Fontana et ah, 2002). Evidence for a carnosine-NO adduct has also been published (Nicoletti et al., 2007). 

Yokoyama, H., Kurolwa, H., and Yano R Araki, T. (2008). Targeting reactive oxygen species, reactive nitrogen species and inflammation in MPTP neurotoxicity and Parkinson s disease. Neurol. Sci. 29, 292-301. 

---