Ionotropic glutamate receptor that functions as a cation- permeable ligand-gated ion channel, gated by L-glutamate and the glutamatergic agonist kainic acid. Binding of the excitatory neurotransmitter L-glutamate induces a conformation change, leading to the opening of the cation channel, and thereby converts the chemical signal to an electrical impulse. The receptor then desensitizes rapidly and enters a transient inactive state, characterized by the presence of bound agonist (PubMed:7719709). In association with GRIK2, involved in presynaptic facilitation of glutamate release at hippocampal mossy fiber synapses (By similarity). {ECO:0000250|UniProtKB:B1AS29, ECO:0000269|PubMed:7719709}. This is the function of GRIK3 (glutamate ionotropic receptor kainate type subunit 3, Ensembl gene identifier ENSG00000163873).