ADORA2A and Parkinson disease: A2AR knockout (KO) mice allow assessing if the ergogenic effect of caffeine persists in the absence of A2AR; the use of SCH 58261, the current reference for A2AR antagonists32,33, allows directly assessing the ergogenic role of A2AR. SCH 58261 has excellent selectivity and affinity for A2AR32,33, and affords motor benefits in animal models of Parkinson's disease as does caffeine, supporting the recent FDA approval of the A2AR antagonist Istradefylline for PD treatment33.