Glutamate receptor ionotropic, kainate (KAR)

Glutamate receptor ionotropic, kainate (KAR) is a member of the ionotropic glutamate receptor family, functioning as a ligand-gated cation channel primarily in the central nervous system. KARs assemble as tetramers composed of five possible subunits (GluK1–GluK5) and mediate excitatory neurotransmission upon activation by glutamate or exogenous agonists like kainic acid. KARs play a key role in both fast synaptic transmission and the modulation of synaptic plasticity, and are expressed postsynaptically as modulators of excitation and presynaptically as regulators of neurotransmitter release. Structural and functional diversity among KAR subunits enable distinct roles in neuronal development, circuit formation, and pathology. Dysregulation and altered KAR function contribute to neurological and psychiatric diseases including epilepsy, depression, schizophrenia, and neurodegenerative diseases. KARs are considered important therapeutic targets, with ongoing research into agonists, antagonists, and allosteric modulators for potential interventions.

Other names

Kainate receptorKainic acid receptorIonotropic glutamate receptor, kainate subtypeGluK1–GluK5GluR5–GluR7KA1, KA2

Agonists (e.g., kainic acid, glutamate): activate the receptor and open the cation channel, resulting in depolarization and excitatory neurotransmission. Antagonists: block receptor activation by competing with agonist binding, inhibiting channel opening. Positive allosteric modulators: enhance receptor activity or prolong channel opening, often by stabilizing open or non-desensitized conformations.