NOS2 and Parkinson disease: The elevated level of iNOS and NO production in microglia was associated with the progressive loss of dopaminergic neurons in culture (Le et al., 2001) and in an animal model of PD (Liberatore et al., 1999; Dehmer et al., 2000; Kokovay and Cunningham, 2005; Aquilano et al., 2008).