Characterization of the Adenosine Pharmacology of Ticagrelor Reveals Therapeutically Relevant Inhibition of Equilibrative Nucleoside Transporter 1

Introduction:Studies have shown that ticagrelor has a further adenosine-mediated mechanism of action in addition to its potent inhibition of the P2Y12 receptor, which may explain some of ticagrelor’s clinical characteristics. This study aimed to further characterize the adenosine pharmacology of ticagrelor, its major metabolites, and other P2Y12 receptor antagonists.Methods:Inhibition of nucleoside transporter-mediated [3H]adenosine uptake by ticagrelor, its major metabolites, and alternative P2Y12 antagonists was examined in recombinant Madin-Darby canine kidney (MDCK) cells. The pharmacology of ticagrelor and its major metabolites at adenosine A1, A2A, A2B, and A3 receptor subtypes was examined using in vitro radioligand binding and functional assays and ex vivo C-fiber experiments in rat and guinea pig vagus nerves.Results:Ticagrelor (and less effectively its metabolites) and the main cangrelor metabolite inhibited [3H]adenosine uptake in equilibrative nucleoside transporter (ENT) 1-expressing MDCK cel...