Biochem/physiol Actions

RO5256390 is an orally available partial agonist that targets trace amine-associated receptor 1 (TAAR1) with high affinity (Ki in nM = 0.9/mouse, 4.1/human, 9.1/rat, 24/monkey TARR1), potency (EC50 in nM/relative efficacy with respect to β-phenylethylamine = 1.3/0.59/mouse, 17/0.81/human, 47/0.76/rat, 251/0.85/monkey TARR1-dependent cellular cAMP production), and selectivity (by a 112-receptor/channel/transporter and a 42-enzyme panel), without agonistic activity toward mouse TAAR4-expressing cells even at a high concentration of 30 μM. When applied via oral administration (0.003-1 mg/kg), RO5256390 exhibits similar in vivo efficacy as the full agonist RO5256390 in blocking psychostimulants-induced hyperlocomotion in mice.