ADORA2A and Alzheimer disease: Microglia are attracting attention in the field of AD because microglial cells are involved in the inflammation that occurs in the brain of patients and because microglia could acquire a neuroprotective phenotype, generally known as M2 as opposed to M1 or pro-inflammatory; among the several GPCRs expressed in these cells, A2AR is an attractive target to regulate microglial activation and polarization [30,33,40,67,68,69,70,71,72,73,74,75,76,77].