NOS2 and Huntington disease: More specifically, we evaluated the expression of the inducible isoform of nitric oxide synthase (iNOS), a well‐established source of nitric oxide during inflammation of the central nervous system (CNS) and considered a functional marker of M1 phenotype microglia.41 Evidence of increased iNOS expression has been observed in HD animal models.43 In line with these findings, we found an elevated expression of iNOS in the striatum of saline‐treated R6/2 mice when compared with wild‐type mice (Figure 5D, P < 0.001).