Theme |
Gastrointestinal Diseases and NO |
Title |
Nitric Oxide in Relation to Infections, Inflammation and Immunity |
Author |
Takaaki Akaike |
Department of Microbiology, Kumamoto University School of Medicine |
Author |
Hiroshi Maeda |
Department of Microbiology, Kumamoto University School of Medicine |
[ Summary ] |
A great deal of attention has been given to the diverse functions of NO. Two different NO-dependent signal transductions are now known to occur inbiological systems. One is cyclic GMP(CGMP) -mediated pathway via the activation of soluble guanylate cyclase, the other is through cGMP-independent mechanisrn. Nitrosylation and nitration appear to be critically involved in various cGMP-independent biological phenomena caused by NO. It is now conceivable that the biological functions of NO are partly mediated by the oxidizedforms of NO such as peroxynitrite and NOx, rather than by NO perse. In particular, the overproduction of NO, caused by inducible NO synthase willlead to appreciable levels of reactive nitrogen oxides, and thus may contribute to the pathogenesis of infectious diseases and inflammation, as well as to immunopathogenesis. In this article, the physiological and pathological functions of NO were discussed,in light of its unique chemical reactivity in biological systems. |