Kainate receptor-mediated synaptic transmissions in the adult rodent insular cortex

Kohei Koga, Su Eon Sim, Tao Chen, Long Jun Wu, Bong Kiun Kaang, Min Zhuo

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

Kainate (KA) receptors are expressed widely in the central nervous system and regulate both excitatory and inhibitory synaptic transmission. KA receptors play important roles in fear memory, anxiety, and pain. However, little is known about their function in synaptic transmission in the insular cortex (IC), a critical region for taste, memory, and pain. Using whole cell patch-clamp recordings, we have shown that KA receptors contribute to fast synaptic transmission in neurons in all layers of the IC. In the presence of the GABAA receptor antagonist picrotoxin, the NMDA receptor antagonist AP-5, and the selective AMPA receptor antagonist GYKI 53655, KA receptor-mediated excitatory postsynaptic currents (KA EPSCs) were revealed. We found that KA EPSCs are 5-10% of AMPA/KA EPSCs in all layers of the adult mouse IC. Similar results were found in adult rat IC. KA EPSCs had a significantly slower rise time course and decay time constant compared with AMPA receptor-mediated EPSCs. High-frequency repetitive stimulations at 200 Hz significantly facilitated the summation of KA EPSCs. In addition, genetic deletion of GluK1 or GluK2 subunit partially reduced postsynaptic KA EPSCs, and exposure of GluK2 knockout mice to the selective GluK1 antagonist UBP 302 could significantly reduce the KA EPSCs. These data suggest that both GluK1 and GluK2 play functional roles in the IC. Our study may provide the synaptic basis for the physiology and pathology of KA receptors in the IC-related functions.

Original languageEnglish (US)
Pages (from-to)1988-1998
Number of pages11
JournalJournal of neurophysiology
Volume108
Issue number7
DOIs
StatePublished - Oct 1 2012

Keywords

  • GluK1
  • GluK2
  • Kainate receptor
  • Pyramidal neuron

ASJC Scopus subject areas

  • Neuroscience(all)
  • Physiology

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