Potencial terapêutico dos inibidores da óxido nítrico sintase (NOS) / Therapeutic potential of the inhibitors of nitric oxide synthase

RESUMO

Nitric oxide (NO) is an inorganic gas which accounts for the biological properties of EDRF (endothelium derived relaxing factor). It is important to control the blood flow and arterial pressure. In addition, NO is considered a messenger molecule in the central and periferic nervous system and a mediator of immune and inflammatory responses. Formation of NO from L-arginine aminoacid requires participation of a soluble enzyme, the nitric oxide synthase (NOS). Three isoenzymes of NOS have been identified in humans isoform I, expressed constitutively in brain; isoform II which is usually not constitutively expressed but can be present in cytokine-induced cells; and isoform III, expressed in endothelials cells. Analogues of L-arginine age competitively inhibiting the nitric oxide production. Inhibitors of NOS - been the most citated L-NOARG (NG-nitro-L-arginine), L-NAME (NG-nitro-L-arginine metil ester) and L-NMMA (NG-monometil-L-arginine) - have beem used in many studies for elucidation the mechanism of NO synthesis and its function in different biologic systems. This review discusses the function of L-arginine/NO pathway as well as the possible therapeutic alternatives for the inhibition of NOS in multiple disciplines.