RRAGA and Alzheimer disease: Interestingly, previous studies also found ADORA2A in the striatopallidal and hippocampal neurons.[21, 28] Others discovered that ADORA2A was detected in the neurons other than the astrocytes, oligodendrocytes, and microglia from aging human brains and Alzheimer's disease brains.[22c] Importantly, ADORA2A antagonist Istradefylline significantly decreased the immobility time and attenuated the depressive‐like behaviors in the RagA transgenic mice (Figure 4F,G).