The Role of Nitric Oxide in Health and Diseases

Context: Nitric oxide (NO) is a free radical and synthesized by three Nitric Oxide isoforms. NO is a biological messenger with many important effects on variety of biological processes. NO at low concentrations is beneficial, but has harmful effects on body health in high levels. The purpose of this review was to investigate the role of NO in health and diseases. Evidence Acquisitions: We conducted a literature review on published English articles using databases from PubMed, SCOPUS, Google Scholar, and IranMedex between 1984 and 2013. First, 798 articles were identified; 92 articles were finally included in this literature review based on the inclusion criteria. There was an important association between serum/plasma NO levels and cardiovascular disease, hypercholesterolemia, heart failure, myocarditis, myocardial ischemia, atherosclerosis, hypertension, diabetes and dysglycemia, thyroid disorders, metabolic syndrome and obesity. Furthermore, NO has a strong trace in neurodegenerative diseases. Conclusions: All three NOS isoforms play important roles as dichotomous effects in human biology and diseases. NO has a very short half-life, so its direct determination has limitations. The most common method for NO determination is based on the Griess reaction and NO metabolites determination.