In animal models of PD increased TNF mRNA and protein are detectable in the midbrain within hours of in vivo administration of a neurotoxic dopamine analog, 6-hydroxydopamine (6-OHDA) [143], the mitochondrial complex I inhibitor 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) [144-146], and the bacterial endotoxin lipopolysaccharide (LPS) [147]. Here, TNF is linked to Parkinson disease.