Nitric oxide.

Abstract

Nitric oxide is a gas generally known by its chemical formula NO, or NO. The dot denotes an unpaired electron, which is the definition of a free radical; pbssessing this, NO is highly reactive and quite -different from the anaesthetic agent nitrous oxide (N20), which is extremely stable. Until recently, NO was best known as a constituent of car exhaust fumes, contributing to the photochemical smog of cities such as Los Angeles. In contrast, the work which crucially altered this perception was performed in a leafy Kentish suburb at the Wellcome Foundation in Beckenham, UK. In 1987, it was shown that NO was the long sought endothelium derived relaxing factor (EDRF).' This was a crucial discovery for cardiovascular biology, and it soon became evident that NO was produced by many cell types and performed diverse functions, including inhibition of platelet aggregation and mediation of the cytotoxic action of activated macrophages, and had a role in central and peripheral neurotransmission.NO is enzymically synthesised from L-arginine by oxidation of one of the terminal guanidino nitrogen atoms of L-arginine,2-a process inhibited by L-arginine analogues such as N0-monomethyl-L-arginine (LNMMA).

Óxido nítrico: revisão

“…A molécula do NO tem um elétron não pareado e reage facilmente com oxigênio, radical superóxido, ou metais de transição, como ferro, cobalto, manganês ou cobre 6 . O NO tem alta afinidade com o heme, encontrado em proteínas intracelulares (óxido nítrico-sintase, cicloxigenase e guanilato ciclase) e também liga-se a grupos -SH, formando tiol 10 ; é um gás incolor e estável, moderadamente solúvel em água e sua meiavida varia de 3 a 60 segundos, mas pode ser maior devido ao ambiente do NO, concentração de O 2 e O· 2 - 6,[11][12][13][14][15][16] . Parece que o NO exerce maior efeito na imunidade inespecífica do que na específica, exibindo atividade citostática ou citocida contra uma notável amplitude de microorganismos patogênicos 8,17 .…”

Decreased Nitric Oxide Production in Patients with Behçet’s Disease

“…They are rapidly activated by intracellular Ca 2+ fluxes and produce small quantities of NO. Inducible NOS (type II) is a Ca 2+ -independent isoform and can be induced in many cells including hepatocytes, macrophages, neutrophils, smooth muscle cells and chondrocytes by cytokines and endotoxin during inflammatory and infectious processes and generates large amounts of NO [5, 6, 7]. NO has been implicated in a variety of biological processes such as the relaxation of vascular smooth muscle cells, neurotransmission, immunity and inflammatory processes.…”

“…NO has been implicated in a variety of biological processes such as the relaxation of vascular smooth muscle cells, neurotransmission, immunity and inflammatory processes. NO has also been postulated in several pathological processes related to immunological, cardiovascular and neurological disorders, infections and cancer [6]. Determination of the NO radical itself is difficult because of its radical nature and very short half-life.…”

Effect of Plasma from Patients with Behçet’s Disease on the Production of Nitric Oxide in Cultured Human Umbilical Vein Endothelial Cells

“…Type II is a Ca 2+ -independent isoform that can be induced in large amounts by cytokines and endotoxins during inflammatory or infectious processes in many cells, including hepatocytes, macrophages, neutrophils, smooth muscle cells and chondrocytes. NO derived from eNOS has been implicated in a variety of biological processes such as relaxation of vascular smooth muscle cells, which causes vasodilatation and an anticoagulant effect [5,6]. On the other hand, it has been shown that oxidized low-density lipoprotein decreases the expression of eNOS [7].…”