Studies on the brains of the postmortem PD patients have shown the presence of activated microglia cells in the substantia nigra pars compacta [31] and revealed an elevation of inflammatory regulators, including inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression in the striatum area [32]. This evidence concerns the gene NOS2 and Parkinson disease.