University of Arkansas, Fayetteville


Nitric oxide (NO) is inactivated in the human body when exposed to superoxide (02-). This reaction forms peroxynitrite (ONOO). Superoxide is produced in the cardiac system by several mechanisms, including NAD(P)H oxidase. Superoxide dismutase (SOD) breaks down superoxide into oxygen and hydrogen peroxide. This prevents superoxide from reacting with nitric oxide and allows normal function to take place. Superoxide and peroxynitrite are main contributors to vascular disease in the human body, in particular hypertension.