A class of cell surface receptors for purines that prefer ATP or ADP over adenosine. P2 purinergic receptors are widespread in the periphery and in the central and peripheral nervous system. Subtypes have been proposed, usually designated P2 x, y, z, and t. P2x receptors may mediate fast synaptic transmission by ATP. The ADP-preferring P2t receptors in platelets stimulate aggregation.