Involvement of post-synaptic kainate receptors during synaptic transmission between unitary connections in rat neocortex

Eur J Neurosci. 2003 Jun;17(11):2344-50. doi: 10.1046/j.1460-9568.2003.02677.x.


The properties of functional kainate receptor-mediated EPSCs were studied in acute slices from 19-35-day-old rats. EPSCs elicited in pyramidal and fast-spiking cells in layers 2/3 and 5 of the rat motor cortex by extracellular single shock stimulus in the presence of GYKI 53655 and D-2-amino-5-phosphopentanoic resulted in a residual current. This current was not enhanced by cyclothiazide but was blocked by 6-cyano-7-nitroquinoxalin-2,3-dione and is thought to be mediated by kainate receptors. These kainate receptor-mediated currents displayed a wide range of time courses depending on which pre-synaptic fibres were activated. With paired recordings, unitary EPSCs elicited in pyramidal cells were almost totally blocked by GYKI 53655 and D-2-amino-5-phosphopentanoic. However, when L-transpyrrolidine-2,4-dicarboxylate (PDC), a glutamate uptake blocker, was introduced in the bath, the amplitude of kainate receptor-mediated currents, which is resistant to GYKI 53655 and D-2-amino-5-phosphopentanoic, was revealed. The rise and decay time constants of the kainate receptor-mediated currents were identical to control EPSCs. PDC was not required to reveal the kainate receptor-mediated currents elicited in fast-spiking cells which also displayed similar rise and decay time constants to the control EPSCs. Excitatory input onto pyramidal and fast-spiking cells in the neocortex mediated by kainate receptors contributed between 14 and 40% of the total control unitary EPSCs which displayed identical time courses to the AMPA receptor-mediated component of the EPSCs. Post-synaptic kainate receptors at connected pyramidal cell synapses may be located extra-synaptically.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 6-Cyano-7-nitroquinoxaline-2,3-dione / pharmacology
  • Animals
  • Antihypertensive Agents / pharmacology
  • Benzodiazepines / pharmacology
  • Benzothiadiazines / pharmacology
  • Dicarboxylic Acids / pharmacology
  • Drug Interactions
  • Electric Conductivity
  • Excitatory Amino Acid Antagonists / pharmacology
  • Excitatory Postsynaptic Potentials / drug effects
  • In Vitro Techniques
  • Membrane Potentials / drug effects
  • Neocortex / cytology
  • Neocortex / physiology*
  • Neural Pathways / physiology*
  • Neurotransmitter Uptake Inhibitors / pharmacology
  • Patch-Clamp Techniques
  • Pyramidal Cells / drug effects
  • Pyramidal Cells / physiology*
  • Pyrrolidines / pharmacology
  • Rats
  • Rats, Wistar
  • Receptors, Kainic Acid / physiology*
  • Synaptic Transmission / physiology*
  • Time Factors
  • Valine / analogs & derivatives*
  • Valine / pharmacology


  • Antihypertensive Agents
  • Benzothiadiazines
  • Dicarboxylic Acids
  • Excitatory Amino Acid Antagonists
  • Neurotransmitter Uptake Inhibitors
  • Pyrrolidines
  • Receptors, Kainic Acid
  • Benzodiazepines
  • GYKI 53655
  • 6-Cyano-7-nitroquinoxaline-2,3-dione
  • 2-amino-5-phosphopentanoic acid
  • pyrrolidine-2,4-dicarboxylic acid
  • Valine
  • cyclothiazide