Nitric Oxide

Nitric oxide (NO) is an unprecedented neurotransmitter. NO is a small, labile, lipid-permeable free radical molecule. It is synthesized by NO synthase (NOS) and diffuses from its site of synthesis to targets in surrounding cells. NO forms covalent and noncovalent linkages with protein and nonprotein targets to elicit its biological effects. The process of covalently linking NO with protein targets is termed S-nitrosylation, and has become a primary focus of research in the field. NO depends on its small size, reactivity, and diffusibility more than any other biological molecule to exert its biological effects. NO plays important roles in the normal function as well as the dysfunction of the brain, paradoxically exhibiting cytoprotective as well as cytotoxic properties in different contexts.