ADORA2A and early-onset autosomal dominant Alzheimer disease: This A2AR-related neuroprotection in different brain regions that are devoid of the particularly high density of A2AR that is present in striatal medium spiny neurons depends on a different population of A2AR located in excitatory synapses, as concluded in animal models of Alzheimer’s disease [26,27] or convulsions [28] and possibly also in PD [29].