(2R,4R)-APDC is a highly potent and highly selective agonist for mGluR-2 (group II metabotropic glutamate receptors). The compound is useful for investigating the functions of metabotropic glutamate receptors in situ. (2R,4R)-APDC inhibits the NADPH-oxidase dependent ROS system. (2R,4R)-APDC is an activator of mGluR-3.