While ADP is the known endogenous agonist of P2Y13 (EC50 = 60 nM),221 2-MeSADP, a nonselective P2Y12/13 agonist, is even more potent at this receptor.271 However, inosine 5′-diphosphate sodium salt (IDP) is the preferential selective P2Y13 agonist with 5-fold more potency for hP2Y13 over the P2Y12 receptor.306 Furthermore, IDP with EC50 = 9.2 nM is more potent at murine P2Y13 than at human P2Y13 (EC50 = 552 nM).306 Inosine 5′-diphosphate sodium salt is currently considered as a potent P2Y13 receptor agonist.306
