GluR6/KA2 kainate receptors mediate slow-deactivating currents.
Kainate receptors (KARs) are ionotropic glutamate receptors contributing to EPSCs with a slow-decaying component that is likely essential for synaptic integration. The slow kinetics of KAR-EPSCs markedly contrasts with the fast kinetics reported for recombinant KARs expressed in heterologous systems, for reasons that remain unexplained. Here we have studied the properties of recombinant heteromeric GluR6/KA2 receptors, which compose synaptic KARs. We report that, in response to brief glutamate applications, currents mediated by recombinant GluR6/KA2 receptors, but not GluR6 receptors, decay with a time course similar to KAR-EPSCs. Model simulations suggest that, after brief agonist exposures, GluR6/KA2 currents undergo slow deactivation caused by the stabilization of partially bound open states. We propose, therefore, that the GluR6/KA2 gating features could contribute to the slow KAR-EPSC decay kinetics.
Barberis
Andrea
A
Laboratoire Physiologie Cellulaire de la Synapse, Centre National de la Recherche Scientifique Unité Mixte de Recherche 5091, Bordeaux Neuroscience Institute, University of Bordeaux 2, 33077 Bordeaux, France. andrea.barberis@iit.it
Sachidhanandam
Shankar
S
Mulle
Christophe
C
D002460:Cell Line; D006801:Humans; D015640:Ion Channel Gating / Q000502:physiology; D019599:Mossy Fibers, Hippocampal / Q000502:physiology; D018092:Kainic Acid Receptors / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology*; D013997:Time Factors; D000097806:GluK2 Kainate Receptor
D018092:Kainic Acid Receptors; D000097806:GluK2 Kainate Receptor; C511773:GRIK5 protein, human