Nitric oxide. New discoveries, biomedical implications

Nitric oxide (NO) has been identified as a naturally-occurring metabolite in mammalian systems, formed from the amino acid arginine in response to a variety of physiological stimuli. It appears to function in cell-cell communication and may act either directly or through the stimulation of cyclic GMP synthesis in the regulation of such diverse functions as smooth muscle relaxation, inhibition of platelet aggregation and adhesion, central nervous system activity, and cytostasis. The significant role(s) could have important biomedical implications since perturbations in the biosynthesis, release or actions of NO could lead to hypertension, CNS dysfunction or increased susceptibility to infection. Understanding the enzymology and regulation of this pathway in various tissues may lead to development of pharmacological agents specifically designed for the rational control of nitric oxide formation and action.