Kainate Receptor-Mediated Responses in the CA1 Field of Wild-Type and GluR6-Deficient Mice

• DOI: 10.1523/jneurosci.19-02-00653.1999
• Publication Date: 2018-04-03T12:00:23Z
• Authors: Ingrid Bureau; Serge Bischoff; Steve F. Heinemann; Christophe Mulle
• Keywords: Male; Mice, Knockout; Neurons; 0301 basic medicine; 0303 health sciences; Kainic Acid; GluK2 Kainate Receptor; Pyramidal Cells; Action Potentials; In Vitro Techniques; Hippocampus; Synaptic Transmission; Mice; 03 medical and health sciences; Receptors, Kainic Acid; Interneurons; Excitatory Amino Acid Agonists; Animals; Receptors, AMPA; Evoked Potentials; Excitatory Amino Acid Antagonists; In Situ Hybridization

Kainate receptors are abundantly expressed in the hippocampus. Mice with disruption of kainate receptor subunits allow the genetic dissection of the role of each kainate receptor subunits in the synaptic physiology of the hippocampus, as well as in excitotoxic processes. We have compared the action of domoate and kainate on CA1 pyramidal neurons in slices from wild-type and GluR6−/− mice. The difference in the amplitude of inward currents evoked by domoate and kainate between wild-type and GluR6−/− mice demonstrates the presence of functional kainate receptors in CA1 pyramidal neurons. Block of domoate-activated inward currents by the AMPA receptor antagonists 2,3-dihydroxy-6-nitro-7-sulfonyl-benzo(F)quinoxaline (1 μm) and 1-(4-aminophenyl)-3-methylcarbamyl-4-methyl7,8-methylenedioxy-3,4-dihydro-5H-2,3-benzodiazepine) (GYKI 53655) (50 μm) is complete in GluR6−/− mice but only partial in wild-type mice. In the presence of GYKI 53655, kainate receptor activation dramatically increases the frequency of spontaneous IPSCs in CA1 pyramidal cells from wild-type, as well as GluR6−/−, mice. This results from the kainate receptor-mediated activation of a sustained inward current and an increased action potential firing in afferent GABAergic interneurons of the CA1 field. These effects are observed in wild-type, as well as GluR6−/−, mice. Kainate receptors also decrease the amplitude of evoked IPSCs in CA1 pyramidal cells by increasing synaptic failures in wild-type and GluR6−/− mice. These results indicate that in CA1 pyramidal cells, distinct subtypes of kainate receptors mediate several functionally antagonistic effects.