Role of iNOS-NO Pathway in Digestive System

10.4247/AM.2013.ABD049

Hai-Yan Jing；Xiao-Long Zhu

gastrointestinal functions ； gut ； iNOS ； nitric oxide ； nitric oxide synthase

Adaptive Medicine

5卷1期（2013 / 03 / 01）

13 - 20

英文

In recent years, nitric oxide (NO), a diffusible universal messenger, has been considered to mediate cell-cell communication throughout the body. However, NO shows a dual behavior. On one hand, at physiological concentrations, and released through the constitutive synthase, it regulates house-keeping functions. NO participates in the regulation of blood flow, maintenance of vascular tone, and modulation of the activity of the mastocytes. It also plays a key role as a neurotransmitter in the central and peripheric nervous system. On the other hand, the overproduction of NO by the inducible synthase exhibits cytotoxic activity because its interaction with reactive species can produce peroxinitrites (ONOO) and other compounds, which are highly damaging to the tissues. NO is generated from L-arginine, oxidated by nitric oxide synthase (NOS). Compared with two constitutive NOS (eNOS and nNOS), inducible nitric oxide synthase (iNOS) synthesizes NO in high amounts and in a calciumindependent manner. Up-regulation of the production ofNO via expression of iNOS is related to various aspects of gastrointestinal dysfunction, such as gastroenteritis, peristalsis delay and tumor development. Hence, the functional role of iNOS-NO pathway in the digestive system is raising more attention from researchers. In this review, we aim to give an overview of the existing literature and we will focus on the regulation, distribution, and main function of iNOS in the digestive system.