Inducible nitric oxide synthase and cardiac dysfunction in salt-sensitive hypertension
Nitric oxide (NO) is generated from l-arginine by nitric oxide synthase (NOS), an enzyme that has three isoforms. Endothelial (NOS3) and neural (NOS1) isoforms are so labelled because they were initially identified in endothelial cells and neurones, although they have subsequently been identified in many different cell types. Both are expressed constitutively and activated by Ca2+. Inducible NOS (NOS2) was first identified in macrophages but its expression can be induced in almost any cell type.