Kainate Receptors

Kainate receptors are members of the ionotropic class of glutamate receptors, which also includes NMDA and AMPA receptors. Composed of subunits GluK1-5, kainate receptors are found both pre- and post-synaptically and modulate both excitatory and inhibitory synaptic transmission.

Literature (2)
Gene Data

Kainate Receptor Agonists

Cat. No. Product Name / Activity
1107 ATPA
Potent and selective GluK1 kainate agonist
0307 (S)-(-)-5-Iodowillardiine
Highly potent and subtype-selective kainate agonist
7065 Kainic acid (synthetic)
Kainate agonist; excitant and neurotoxin

Kainate Receptor Antagonists

Cat. No. Product Name / Activity
2728 ACET
Potent kainate antagonist; displays selectivity for GluK1-containing receptors
0190 CNQX
Potent and selective non-NMDA iGluR antagonist
1045 CNQX disodium salt
Potent non-NMDA iGluR antagonist; more water soluble form of CNQX (Cat. No. 0190)
0189 DNQX
Selective non-NMDA iGluR antagonist
2312 DNQX disodium salt
Selective non-NMDA iGluR antagonist; water-soluble salt of DNQX (Cat. No. 0189)
0845 Evans Blue tetrasodium salt
Non-NMDA iGluR antagonist; P2X antagonist; also inhibits L-glutamate uptake into synaptic vesicles
2555 GYKI 53655 hydrochloride
Non-competitive non-NMDA iGluR antagonist
5032 Talampanel
Non-competitive non-NMDA iGluR antagonist
3620 Topiramate
GluK1 antagonist; inhibits carbonic anhydrase (CA) II and IV; also positive allosteric modulator of GABAA receptors
2078 UBP 296
Potent and selective kainate antagonist; selective for GluK1-containing receptors
1766 UBP 301
Kainate antagonist
2079 UBP 302
Potent and selective kainate antagonist; active enantiomer of UBP 296 (Cat. No. 2078)
3621 UBP 310
GluK1-selective kainate antagonist
2345 ZK 200775
Competitive non-NMDA iGluR antagonist


Cat. No. Product Name / Activity
1777 Arctigenin
Binds to kainate receptors; neuroprotective. Also inhibits IκBα phosphorylation and MEK1

Kainate receptors are cation-selective, ligand-gated ion channels, which cause a strong membrane depolarization in response to glutamate binding. Like other members of the ionotropic glutamate receptor family, they are named for their specific activation by kainate (kainic acid), which was initially isolated from the algae Digenea simplex.

Kainate receptors exist as tetramers, composed of the subunits GluK1 to 5. Each subunit has an extracellular N-terminus, a cytoplasmic C-terminus, three membrane-spanning segments and a re-entrant loop that dips into the membrane from the cytoplasmic face to form the pore. It is thought that subunits GluK4 and K5 (formerly named KA1 and KA2, respectively) act as modulatory subunits, conferring high affinity binding for glutamate. When expressed in vitro, homomeric receptors of GluK1 or K2 subunits are non-functional.

The GluK1 and K2 subunits of kainate receptors, like the GluA2 subunit found in AMPA receptors may undergo post-translation modification at a specific amino acid residue within the re-entrant loop, termed the Q/R site. The amino acid expressed at this site, either glutamine (Q) or arginine (R), modulates the Ca2+ permeability of the ion channel.

Kainate receptors are expressed on the presynaptic membrane of both excitatory and inhibitory synapses, where their actions either facilitate or inhibit neurotransmitter release. Activation of kainate receptors results in increased cation permeability and depolarization of the presynaptic neuron. The subunit conformation, and therefore Ca2+ permeability, of a specific kainate receptor has an effect on its presynaptic modulatory activity.

Compared to other glutamate receptors, kainate receptors play a relatively small role in excitatory synaptic signaling. When expressed on postsynaptic membranes they produce small, slow excitatory postsynaptic potentials (EPSPs). These small changes in ion balance affect the overall likelihood of postsynaptic cell firing.

Kainate receptors have been linked to development of temporal lobe epilepsy in humans. Additionally, kainate dosing can be used to generate an animal model of epilepsy via a process known as kindling. It is thought that this occurs via activation of GluK4 and K5 containing receptors, which are highly expressed in the hippocampus, the likely site of seizure onset in this model. Alleles of the GluK2 subunit have also been linked to Huntington's disease, autism and schizophrenia.

External sources of pharmacological information for Kainate Receptors :

Literature for Kainate Receptors

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Kainate Receptor Gene Data

Gene Species Gene Symbol Gene Accession No. Protein Accession No.
GluK1 (formerly GluR5) Human GRIK1 NM_175611 P39086
Mouse Grik1 NM_146072 Q60934
Rat Grik1 NM_017241 P22756
GluK2 (formerly GluR6) Human GRIK2 NM_175768 Q13002
Mouse Grik2 NM_010349 P39087
Rat Grik2 NM_019309 P42260
GluK3 (formerly GluR7) Human GRIK3 NM_000831 Q13003
Mouse Grik3 NM_001081097 NP_001074566
Rat Grik3 NM_181373 P42264
GluK4 (formerly KA-1) Human GRIK4 NM_014619 Q16099
Mouse Grik4 NM_175481 Q8BMF5
Rat grik4 NM_012572 Q01812
GluK5 (formerly KA-2) Human GRIK5 NM_002088 Q16478
Mouse Grik5 NM_008168 Q61626
Rat Grik5 NM_031508 Q63273