Nitric oxide in mucosal defense: A little goes a long way

Nitric oxide (NO) is now recognized as an important modulator of an enormou s number of physiological processes, ranging from blood pressure regulation to neuronal transmission to penile erectile function. In the gastrointesti nal tract, NO also participates in many physiological and pathophysiologica l processes. In this review, we summarize the contribution made by NO to th e ability of the gastrointestinal mucosa to resist injury induced by lumina l toxins and to defend against microbial invasion. We also review some of t he main features of NO chemistry and the potential of NO as a target for ne w drugs to treat gastrointestinal disorders.