In the basal ganglia, CD73, which generates adenosine from extracellular AMP, colocalizes with A2ARs (Augusto et al., 2013) and the enzyme has been recently demonstrated to act a part in A2AR signaling in both PD models and patients (Carmo et al., 2019; Meng et al., 2019). Here, NT5E is linked to Parkinson disease.