Jornal Brasileiro de Patologia e Medicina Laboratorial
Print version ISSN 1676-2444
DUSSE, Luci Maria Sant'Ana; VIEIRA, Lauro Mello and CARVALHO, Maria das Graças. Nitric oxide revision. J. Bras. Patol. Med. Lab. [online]. 2003, vol.39, n.4, pp. 343-350. ISSN 1676-2444. http://dx.doi.org/10.1590/S1676-24442003000400012.
Nitric oxide (NO) is an inorganic and incolor free radical gas containing seven electrons from nitrogen and eigth from oxigen and one unpaired electron. Until midlle of 1980 decade, NO was considered as a member of an undesiderable and envirommental poluents family and as a potential carcinogen agents. At the moment, NO constitutes one of the most important mediators of intra and extra cellular processes. This radical is produced from the L-arginine envolving a reaction mediated by constitutive and inducible NO synthase. NO presents a dubious role, sometimes it brings benefits, sometimes it is harmful. It is envolved in the vascular relaxing and it protects the blood vessels. It constitutes an important cytotoxic mediator on immune activated cells capable of killing pathogenic agents and tumor cells. It also has a role as messager/modulator in a variety of essential biological processes. However, NO is a potentially toxic agent, whose toxicity could be particulary denoted in stress oxidative conditions, by the generation of O2 intermediates and antioxidant system deficiency. Laboratory measurement of NO is complex and the characterization of specific activators and inhibitors of the NO synthesis constitutes the new challenge for a better comprehension and treatment of a number of pathologies. NO studies have been one of the main target for pharmaceutical industries.
Keywords : Nitric oxide; Nitric oxide synthase; Free radical; Stress oxidative.