ADORA2A and type 2 diabetes mellitus: A2AR seem to be the main targets of caffeine to prevent memory impairment since: 1) chronic noxious insults enhance the density of A2AR while reducing that of A1R [11], as now also observed in this model of type 2 diabetes; 2) selective antagonists of A2AR rather than A1R mimic the beneficial effects of caffeine on afflicted memory performance (reviewed in [6], [7]).