ADORA2A and Parkinson disease: Adenosine A2A receptors gene expression was found to be up-regulated in the striata of rats with a 6-OHDA lesion (Pinna et al., 2002), and in the putamen and peripheral blood mononuclear cells (PBMCs) of PD and mild cognitive impairment patients (Calon et al., 2004; Varani et al., 2010; Casetta et al., 2014).