ADX-47273 is a potent and selective mGluR5 receptor PAM (positive allosteric modulator), EC50 = 0.17 μm, with no effect on other mGluR subtypes. [1]

The mGluR (metabotropic glutamate receptor) is a group of G-protein coupled receptors and is active through an indirect metabotropic process. It plays a critical role in regulating synaptic plasticity and neural network activity.

In HEK-293 cell expressing rat mGlu5, ADX-showed 9-fold higher response (EC50 = 0.17 μm) to threshold concentration of glutamate (50 nM) in the fluorometric Ca2+ assays, it also shifted mGlu5 receptor glutamate response curve to the left. [1]

In vivo, ADX47273 increased ERK (extracellular signal-regulated kinase) and CREB (cAMP-responsive element-binding protein) phosphorylation in rat hippocampus and prefrontal cortex. In rat and mouse models that sensitive to antipsychotic treatment, ADX47273 decreased rat conditioned avoidance responding (minimal effective dose = 30 mg/kg i.p.) and reduced mouse ampomorphine-activated climbing (minimal effective dose = 100 mg/kg i.p.) [1]

Reference:
[1] Liu F, Grauer S, Kelley C, Navarra R, Graf R, Zhang G, Atkinson PJ, Popiolek M, Wantuch C, Khawaja X, Smith D, Olsen M, Kouranova E, Lai M, Pruthi F, Pulicicchio C, Day M, Gilbert A, Pausch MH, Brandon NJ, Beyer CE, Comery TA, Logue S, Rosenzweig-Lipson S, Marquis KL.  ADX47273 [S-(4-fluoro-phenyl)-{3-[3-(4-fluoro-phenyl)-[1,2,4]-oxadiazol-5-yl]-piperidin-1-yl}-methanone]: a novel metabotropic glutamate receptor 5-selective positive allosteric modulator with preclinical antipsychotic-like and precognitive activities.  J Pharmacol Exp Ther. 2008 Dec;327(3):827-39.