N-methyl-D-aspartate induces phase shifts in circadian rhythm of neuronal activity of rat SCN in vitro

S. Shibata*, A. Watanabe, T. Hamada, M. Ono, S. Watanabe

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)


The suprachiasmatic nucleus (SCN) acts as a pacemaker for mammalian circadian rhythms. Receptors for excitatory amino acids like N-methyl-D- aspartate (NMDA) and non-NMDA receptors have both been found to play an important role in the transmission of photic information from the retina to the SCN. Therefore, we investigated whether the application of glutamate receptor agonists could reset the phase of the circadian rhythm of SCN firing activity in vitro. Treatment with NMDA (0.1-10 μM) for 15 min or 1 h during the early part of the subjective night produced phase delay, whereas treatment during the late subjective night caused an advance in phase. The phase-response curve for NMDA was similar to that previously obtained in response to light pulses in vivo. Application of DL-α-amino-3-hydroxy-5- methylisoxazole-4-propionic acid hydrobromide (AMPA) (1 or 10 μM), a non- NMDA-receptor agonist, also produced a dose-dependent phase delay of SCN activity. The NMDA-induced phase delay was antagonized by an NMDA-receptor antagonist MK-801. These findings suggest that both NMDA and non-NMDA receptors may be involved in the transmission of information to the SCN via the retinohypothalamic tract. In addition, both the advances and delays in phase caused by NMDA were potentiated by cotreatment with neuropeptide Y, whereas AMPA-induced phase delay was not potentiated by neuropeptide Y. This points to a functional link between NMDA and neuropeptide Y receptor-mediated mechanisms in the SCN.

Original languageEnglish
Pages (from-to)R360-R364
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Issue number2 36-2
Publication statusPublished - 1994 Jan 1
Externally publishedYes


  • geniculohypothalamic tract
  • glutamate
  • in vitro
  • neuropeptide Y
  • retinohypothalamic tract
  • suprachiasmatic nucleus

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)


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