Nitric Oxide (No) A Free Radical And A Messenger Molecule

Nitric Oxide (NO) is a lipophilic free radical diffusible gas that mediates significant and diverse signaling functions in almost every organ system in the body. It is formed from L- arginine a semi- essential amino acid present in the body with the help of three isoform of nitric oxide synthase (e.g. eNOS, nNOS and iNOS), eNOS and nNOS in cardiovascular system and nervous system respectively and inducible form produced during various body stress situations. Pharmacological compounds that release NO have been useful tools for evaluating the broad role of NO in physiology and therapeutics. NO deficiencies have been implicated in the generation and evolution of several disease states. Apart from newly developed drugs e.g. NO- Aspirin, several commonly used cardiovascular drugs exert their useful action, at least in part by modulating the NO pathway. This review discusses the fundamental pharmacological properties and mechanism of action of NO, their physiological effect in various system of the body and pathophysiological role in various disease process e.g. hypertension, coronary artery disease, stroke, shock and neurodegenerative diseases, either because of deficiency or excess of NO.