ADORA2A and Parkinson disease: Adenosine 2A receptor-dopamine D2 receptor (A2AR-D2R) heterodimer is located in the ventral striato-pallidal GABA neurons.335,336 A2AR-D2R heterodimer attracts attention in the field of Parkinson’s disease medication as ligands for A2AR can modulate dopamine signaling in Parkinson’s disease.