Presynaptic AMPA and kainate receptors increase the size of GABAergic terminals and enhance GABA release

Neuropharmacology. 2007 Jun;52(8):1631-40. doi: 10.1016/j.neuropharm.2007.03.010. Epub 2007 Mar 24.

Abstract

In the developing cerebellum, NMDA receptors promote the maturation of axonal terminals of inhibitory interneurons. We compared the effects of AMPA/kainate receptor agonists in cultured cerebellar cells from GAD65-eGFP mice. Both AMPA and kainate augmented granule cell survival without affecting interneurons. The action of kainate was blocked by an AMPA but not by a NMDA receptor antagonist, suggesting AMPA receptor involvement. AMPA and kainate increased the size of the GABAergic terminals and the action of kainate was insensitive to NMDA blockers. Whole cell recordings in granule neurons revealed that chronic treatment for 5 days with kainate as well as NMDA decreased AMPA receptor expression while interneuronal kainate receptors were depressed by kainate treatment. Acute kainate application increased mIPSCs frequency in both granule neurons and interneurons and this effect was only partially blocked by an AMPA receptor antagonist. In contrast to what was reported for NMDA, chronic treatment with kainate induced a significant decrease of the basal mIPSCs frequency but increased the acute action of kainate on mIPSCs. Direct recordings from presynaptic GABAergic terminals suggest that AMPA and kainate receptors are present in developing GABAergic terminals and their activation affects the size of GABAergic terminals and spontaneous GABA release.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Benzodiazepines / pharmacology
  • Cells, Cultured
  • Cerebellum / cytology
  • Dose-Response Relationship, Drug
  • Drug Interactions
  • Excitatory Amino Acid Agonists / pharmacology
  • Excitatory Amino Acid Antagonists / pharmacology
  • Glutamate Decarboxylase / genetics
  • Glutamate Decarboxylase / metabolism
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Inhibitory Postsynaptic Potentials / drug effects
  • Inhibitory Postsynaptic Potentials / radiation effects
  • Interneurons / cytology*
  • Interneurons / drug effects
  • Kainic Acid / pharmacology
  • Membrane Potentials / drug effects
  • Mice
  • Mice, Transgenic
  • Presynaptic Terminals / drug effects
  • Presynaptic Terminals / metabolism*
  • Receptors, AMPA / physiology*
  • Receptors, Kainic Acid / physiology*
  • alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / pharmacology
  • gamma-Aminobutyric Acid / metabolism*

Substances

  • Excitatory Amino Acid Agonists
  • Excitatory Amino Acid Antagonists
  • Receptors, AMPA
  • Receptors, Kainic Acid
  • GYKI 52466
  • Benzodiazepines
  • Green Fluorescent Proteins
  • gamma-Aminobutyric Acid
  • alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
  • Glutamate Decarboxylase
  • glutamate decarboxylase 2
  • Kainic Acid