Receptor for glutamate. L-glutamate acts as an excitatory neurotransmitter at many synapses in the central nervous system. The postsynaptic actions of Glu are mediated by a variety of receptors that are named according to their selective agonists. This receptor binds kainate > quisqualate > glutamate >> AMPA. Tetramer of two or more different subunits. Associates with GRIK1 (both edited and unedited versions), GRIK2, or GRIK3 to form functional channels. Homomeric associations do not produce any channel activity. High expression in the cerebral cortex, pyriform cortex, caudate-putamen, hippocampal complex, medial habenulata and granule cell layer of the cerebellum. Weak expression in globus pallidus, thalamus, colliculi and the reticular thalamic nucleus. From embryonic day 14 through postnatal day 1, high expression in spinal cord, brain and some areas of the PNS. At E17 and E19, high expression in spinal cord, mesencephalon and telencephalic structures as in olfactory neurons and in nasal epithelium. Strong expression also in the pituitary. Belongs to the glutamate-gated ion channel (TC 1.A.10.1) family. GRIK5 subfamily.