Glutamate is the major excitatory neurotransmitter in the vertebrate central nervous system. In addition to its role in normal brain processes, such as learning and memory, imbalances in glutamatergic function can result in excitotoxic neuronal cell death, epileptic seizures or psychiatric diseases. Glutamate stimulates two classes of receptors: 1) glutamate-gated ion channels, so called ionotropic receptors, which are subdivided into the NMDA, AMPA, and kainate types, and 2) G protein-coupled metabotropic glutamate receptors (mGluRs). Research in the Duvoisin lab is currently focused on group-III mGluRs, a subset of related mGluRs that are selectively activated by L-2-amino-4-phosphonobutyric acid (L-AP4, also abbreviated APB). Group-III mGluRs comprise mGluR4, -R6, -R7, and -R8.