NOS2 and Parkinson disease: PD toxicant rodent models, such as MPTP, 6-hydroxydopamine (6-OHDA), lipopolysaccharides (LPS), manganese ethylene bis-dithiocarbamate (maneb) and 1,1′-dimethyl-4,4-bipyridinium dichloride (paraquat), found to have high expression levels of iNOS, nNOS and NO in the brain (see Fig. 4) [[159], [160], [161], [162]].