ABSTRACT
Nitric oxide (NO) has achieved prominence as a ubiquitous, endogenous molecule with a myriad of functions. The discovery of its biologic role has aided our understanding of disease mechanisms, and suggested new treatments for a variety of illnesses. The obligatory role of the endothelium in acetylcholineinduced vasodilation suggested the existence of an endothelium derived relaxing factor (Furchgott and Zawadzki, 1980), now accepted to be NO (Palmer et al., 1987; Ignarro et al., 1987). Nitric oxide formed from L-arginine and molecular oxygen in a reaction catalyzed by NO synthase induces vasodilation through acyclic guanosine monophosphate (cGMP) dependent pathway (Palmer et al., 1988). Since NO exists as a gas it can be delivered by inhalation to the alveoli and then to blood vessels which lie in close proximity to ventilated lung (Figure 26-1).
