RO-4491533 is a drug developed by Hoffmann-La Roche which acts as a potent and selective negative allosteric modulator for group II of the metabotropic glutamate receptors (mGluR<sub>2/3</sub>), being equipotent at mGluR<sub>2</sub> and mGluR<sub>3</sub> but without activity at other mGluR subtypes. In animal studies, RO-4491533 produced antidepressant effects and reversed the effects of the mGluR<sub>2/3</sub> agonist LY-379,268 with similar efficacy but slightly lower potency than the mGluR<sub>2/3</sub> antagonist LY-341,495. A number of related compounds are known, with similar effects in vitro and a fairly well characterized structure-activity relationship.