CNQX increases GABA-mediated synaptic transmission in the cerebellum by an AMPA/kainate receptor-independent mechanism

S. G. Brickley, M. Farrant, G. T. Swanson, S. G. Cull-Candy*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

54 Scopus citations


GABAA receptor-mediated inhibitory synaptic transmission within the CNS is often studied in the presence of glutamate receptor antagonists. However, for nearly a decade it has been known that, in the hippocampus, one of the most commonly used α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)/kainate receptor antagonists, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), can increase the frequency of spontaneous GABAA receptor-mediated postsynaptic currents (sIPSCs). In the present study we examined the effect of CNQX and related compounds on GABA-mediated synaptic transmission in the cerebellum. At various stages of development, low concentrations of CNQX increased the frequency of sIPSCs recorded from granule cells. This effect was independent of the blocking action of CNQX on ionotropic glutamate receptors, as it was not observed with the broad-spectrum glutamate receptor antagonist kynurenate. No increase in sIPSC frequency was observed with the NMDA receptor antagonists d-AP5 or 7-ClK, the selective AMPA receptor antagonists GYKI 52466 or GYKI 53655, or the kainate receptor antagonist NS-102. In contrast, two other quinoxaline derivatives, NBQX and DNQX, were capable of increasing sIPSC frequency. These results demonstrate that the novel excitatory action of CNQX, unrelated to blockade of ionotropic glutamate receptors, is not restricted to the hippocampus and can be observed with structurally related compounds.

Original languageEnglish (US)
Pages (from-to)730-736
Number of pages7
Issue number6
StatePublished - 2001


  • GABA receptors
  • Golgi cell
  • Granule cell
  • IPSCs
  • Quinoxaline derivatives

ASJC Scopus subject areas

  • Pharmacology
  • Cellular and Molecular Neuroscience


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