Nitrogen oxide or nitric oxide, known as endothelium-derived relaxation factor (EDRF), is biologically endogenous from oxygen, NADPH, and L-arginine by different nitrogen oxide synthase (NOS) enzymes. The decrease of inorganic nitrate can also help produce nitrogen oxide. The nitric oxide molecules may be increased using the nitric oxide supplements.
The endothelium or inner layer of blood vessels using nitric oxide to signal the surrounding smooth muscles for relaxation, resulting in vasodilation and increased blood flow. Nitrogen oxide is highly reactive and has a life span of a few seconds, but diffuses freely across the membrane. This attribute makes nitric oxide ideal for transient parrots which are between adjacent cells and autocrine molecular signals in one cell.
As for the body to make nitrogen oxide within the nitrate-nitrite-nitrogen oxide pathway, the decrease of nitrate to nitrite happens in the mouth, with the aid of bacteria, a mandatory and necessary stage. Monitoring of nitrogen oxide status by saliva test monitors plant-derived bioconversion to nitrogen oxide. Rising salivary levels are indicative of a diet rich in leafy vegetables that are often abundant in antihypertensive diet such as DASH diet.