NOS2 and brain disorder: The three isoforms are: (i) NOS type I (NOS1, nNOS, or neuronal), located in specific neurons of the central and peripheral nervous system, [114]; (ii) NOS type II (NOS2, iNOS, or inducible), induced by immunological and inflammatory stimuli and also during brain aging and brain diseases; and (iii) NOS type III (eNOS, NOS3, or endothelial), localized in the vascular endothelium as well as in some central neurons, where it plays a key role in synaptic plasticity and blood flow [115].