ADORA2A and Cognitive impairment: Although acute dexmedetomidine administration may phosphorylate tau protein through α2-AR, it was recently found that dexmedetomidine and clonidine, the agonists of α2-AR, can inhibit sevoflurane-induced tau protein phosphorylation and cognitive impairment by activating α2-AR (Sun et al., 2021).