Studies employing different animal models of PD, such as 6-hydroxydopamine (6-OHDA) injections in basal ganglia or intracerebroventricular in rats [26–29], intraperitoneal injections of heroin contaminant 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in marmosets and mice [30], and specific park genes deleted- mice [31], for example, have also reported changes of CB1 expression in the basal ganglia. Here, CNR1 is linked to Parkinson disease.