Ro 5212773 (EPPTB) is a potent and selective trace amine-associated receptor 1 (TAAR1) antagonist (Ki=0.9 nM for mouse TAAR1), with no significant effects on other TAARs. TAAR1 is a G protein-coupled receptor (GPCR) that is nonselectively activated by endogenous metabolites of amino acids[1][2].