Critical differences in magnitude and duration of N-methyl-D-aspartate (NMDA) receptor activation between long-term potentiation (LTP) and long-term depression (LTD) induction

Naoki Taniike, Yun Fei Lu, Kazuhito Tomizawa, Hideki Matsui

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

The induction of both long-term potentiation (LTP) and long-term depression (LTD) in the hippocampal CA1 region is triggered by the activation of N-methyl-D-aspartate (NMDA) receptors and the subsequent postsynaptic intracellular Ca2+ increase. However, how NMDA receptor activation differs between LTP and LTD induction is unclear. In the present study, we examined the effects of the magnitude and duration of NMDA receptor activation on the induction of LTP and LTD. Partial blockage of NMDA receptors by a low concentration of aminophosphonovaleric acid (APV) (2 μM) prevented the induction of LTP, but not LTD. In contrast, a high concentration of APV (25 μM) blocked both LTP and LTD. Tetanus stimulation-induced LTP was impaired when hippocampal slices were given the tetanus stimulation for more than 5 min. Under partial blockage of NMDA receptors, the prolonged-tetanus stimulation induced LTD but not LTP. This phenomenon was mimicked by the application of glutamate to the slices. Finally, LTD induced by prolonged activation of NMDA receptors was not affected by inhibition of the desensitization of α-amino-3-hydroxy-5-methyhsoxazole-4-propionic acid (AMPA) receptors. These results suggest that critical differences exist between the induction of LTP and that of LTD in terms of both the magnitude and the duration of NMDA receptor activation. The duration of the increase in intracellular Ca 2+ concentration may be critical for determining whether LTP or LTD induction occurs. Copyright

Original languageEnglish
Pages (from-to)21-28
Number of pages8
JournalActa medica Okayama
Volume62
Issue number1
Publication statusPublished - Feb 1 2008

Keywords

  • Hippocampus
  • LTD
  • LTP
  • Learning and memory
  • NMDA receptor

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)

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