Kainate receptors (KARs) are tetramers classified into low-affinity receptor families (GluK1–GluK3) and high-affinity receptor families (GluK4–GluK5) based on their affinity for the neurotoxin kainic acid. KARs share a similar architecture with other ionotropic glutamate receptors; the subunits have a large extracellular domain composed of an amino-terminal domain (ATD) and a ligand binding domain (LBD) and an intracellular carboxy-terminal region.nKARs are expressed in neurons and glial cells throughout the CNS. GluK3 is poorly expressed, appearing in layer IV of the neocortex and dentate gyrus in the hippocampus.nKARs serve a crucial role as modulators of synaptic transmission and plasticity and their dysfunction has been linked to several disease states such as epilepsy, chronic pain and neurodegenerative diseases4. Alteration in the extracellular domain of GluK3, is in linkage disequilibrium with recurrent major depressive disorder patientsand subjects with schizophrenia.