In a rodent model of Parkinson’s disease, treatment with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) or methamphetamine led to higher levels of proinflammatory macrophages (CD16, CD32 and CD86) in dynorphin knockout mice (Dyn-/-) than the wild-type, suggesting anti-inflammatory and neuroprotective properties of PDYN gene products (dynorphin peptides) [50]. This evidence concerns the gene PDYN and Parkinson disease.