Domoic acid induces the release of glutamate in the rat hippocampal CA3 subregion

Neuroreport. 1996 May 17;7(7):1330-4. doi: 10.1097/00001756-199605170-00023.


We investigated the role of kainate receptor activation in modulating the influx of Ca2+ coupled to the exocytotic release of glutamate in rat hippocampal synaptosomal fractions (P2). In whole hippocampus synaptosomes stimulation with domoic acid increased the intracellular free Ca2+ concentration ([Ca2+]i) in a dose-dependent manner with an EC50 of 0.16 microM, whereas the EC50 for kainate was 0.86 microM and for (+/-)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) was 43.04 microM. Stimulation of the synaptosomes with 10 microM domoic acid induced Ca(2+)-dependent release of endogenous glutamate. Also, in synaptosomes isolated from the CA3 sub-region of the hippocampus the domoic acid-induced release of glutamate was higher than that from the dentate gyrus (221.3%), from the CA1 (188.1%) or from the whole hippocampal synaptosomes (131.5%). These results support the existence of a presynaptic kainate receptor which may control the exocytotic release of glutamate in the CA3 sub-region of the rat hippocampus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 6-Cyano-7-nitroquinoxaline-2,3-dione / pharmacology
  • Animals
  • Excitatory Amino Acid Antagonists / pharmacology
  • Glutamic Acid / metabolism*
  • Hippocampus / drug effects*
  • Hippocampus / metabolism
  • In Vitro Techniques
  • Kainic Acid / analogs & derivatives*
  • Kainic Acid / pharmacology
  • Male
  • Rats
  • Rats, Wistar
  • Receptors, Kainic Acid / agonists*
  • Receptors, Presynaptic / agonists*
  • Synaptosomes / drug effects*
  • Synaptosomes / metabolism
  • alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / pharmacology


  • Excitatory Amino Acid Antagonists
  • Receptors, Kainic Acid
  • Receptors, Presynaptic
  • Glutamic Acid
  • 6-Cyano-7-nitroquinoxaline-2,3-dione
  • alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
  • domoic acid
  • Kainic Acid