Phase-resetting efect of 8-OH-DPAT, a serotonin1A receptor agonist, on the circadian rhythm of firing rate in the rat suprachiasmatic nuclei in vitro

Shigenobu Shibata, Atsuko Tsuneyoshi, Toshiyuki Hamada, Keiko Tominaga, Shigenori Watanabe

Research output: Contribution to journalArticlepeer-review

104 Citations (Scopus)


The 5-HTergic neurons in the mesencephalic raphe nuclei provide a robust projection to the hypothalamic suprachiasmatic nucleus (SCN), the site of a putative neuronal circadian pacemaker. Although it has been suggested that 5-HT neurons may play a role in the circadian timing system, this role has not yet been specified. Prosser et al. (Brain Res., 534 (1990) 336-339) reported that 1 h treatments with quipazine induce robust phase shifts in vitro, and that this effect depends upon the circadian time of treatment. However, quipazine is a non-specific 5-HT agonist. Besides, it is reported that the 5-HT1A agonist, 8-hydroxy-2-(di-n-propylamino)tetraline hydrobromide (8-OH-DPAT) affected a circadian rhythm of hamster wheel-running activity. In the present study we investigated whether the 5-HT1A agonist 8-OH-DPAT can reset the phase of the SCN clock when it is isolated in vitro. The present results show that 1 h treatments with 8-OH-DPAT induce robust phase advances in vitro when it was administered during the subjective day. This result suggests that 5HT1A receptor functioning may play a role in modulating the phase of SCN clock, especially during the subjective day.

Original languageEnglish
Pages (from-to)353-356
Number of pages4
JournalBrain Research
Issue number2
Publication statusPublished - 1992 Jun 12
Externally publishedYes


  • 5-Hydroxytryptamine
  • 8-OH-DPAT
  • Circadian rhythm
  • Serotonin 5-HT
  • Suprachiasmatic nucleus

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology


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