Neuronal Nitric Oxide Synthase

Abstract

Nitric oxide synthase (NOS), a flavo‐hemoprotein, regulates nitric oxide (NO) synthesis that has dual biological activities: as an important signalling molecule in vasodilatation and neurotransmission at low concentrations and at higher concentrations as a defensive cytotoxin. In central and peripheral nervous system, neuronal NOS (nNOS) produces NO that has been implicated in modulating physiological functions such as synaptic plasticity, learning, memory and neurogenesis as well as some pathological conditions in which overproduction of NO may lead to the generation of highly reactive species, such as peroxynitrite and stable nitrosothiols, which may cause irreversible cell damage in excitotoxicity, ischaemia, Parkinson, Alzheimer's disease (AD) and depression. NOS‐derived NO also involves in regulation of blood pressure, smooth muscle relaxation and gut peristalsis via peripheral nitrergic nerves.