P2Y receptors are activated by the endogenous ligands ATP, ADP, uridine triphosphate, uridine diphosphate and UDP-glucose. The relationship of many of the cloned receptors to endogenously expressed receptors is not yet established and so it might be appropriate to use wording such as 'uridine triphosphate-preferring (or ATP-, etc.) P2Y receptor' or 'P2Y1-like', etc., until further, as yet undefined, corroborative criteria can be applied [1,2,3,4,5]. Clinically used drugs acting on these receptors include the dinucleoside polyphosphate diquafosol, agonist of the P2Y2 receptor subtype, approved in Japan for the management of dry eye disease , and the P2Y12 receptor antagonists prasugrel, ticagrelor and cangrelor, all approved as antiplatelet drugs [7,8].
Burnstock G, Verkhratsky A. Purinergic signalling and the nervous system. 2012;None:1-715.