Abstract
Nitric oxide (NO) is one of the ten smallest molecules existing, this gas is important as pollutant and also by its role in intracellular signaling in many biological processes. This molecule was distinguished as the Molecule of the Year on 1992; three researchers were awarded the Nobel Prize in Medicine or Physiology, on 1998, by their participation in its discovery and relaxation of smooth muscle in the cardiovascular system. Nitric oxide is enzymatically synthesized by the Nitric Oxide Synthase. This short-lived molecule, 0.5 – 5 s, rapidly reacts with oxygen to generate toxic products, as well as with some macromolecules by reducing its availability; both processes are involved in diverse pathologies. Moreover, nitric oxide production is considered as an unspecific defense mechanism in infections caused by Entamoeba histolytica, Trichomonas vaginalis and Salmonella. Therefore, regulation in NO synthesis is very important to maintain a balance between health and disease.
