Photoperiodic response of serotonin- and galanin-immunoreactive neurons of the paraventricular organ and infundibular nucleus in Japanese quail, Coturnix coturnix japonica

Yuka Haida, Takayoshi Ubuka, Kazuyoshi Ukena, Kazuyoshi Tsutsui, Tadashi Oishi, Satoshi Tamotsu

Research output: Contribution to journalArticle

5 Citations (Scopus)


We investigated the photoperiodic response of serotonin- and galanin (GA)- immunoreactive (ir) cells in the paraventricular organ (PVO) and infundibular nucleus (IF) of the Japanese quail and the interaction of these cells with gonadotropin-releasing hormone (GnRH)-ir neurons in the hypothalamus. Serotonin-ir cells were located in series from the PVO to the IF, and were connected with each other. The number of serotonin-ir cells differed significantly between light and dark phases on the short days (SD), but did not differ between light and dark phases on long days (LD). GA-ir cells were also found in the PVO and IF. The number of GA-ir cells under SD conditions was significantly greater than under LD conditions but did not change diurnally. Both serotonin-ir and GA-ir fibers ran along the GnRH-ir cells in the nucleus commissurae pallii. Serotonin-ir and GA-ir fibers were connected with the GnRH-ir fibers in the external layer of the median eminence (ME). We confirmed that GA-ir fibers were closely associated with serotonin-ir neurons in the PVO and IF. GA-ir neurons have at least 2 routes of regulating GnRH neurons directly, and indirectly via the serotonin-ir cells in the PVO and IF.

Original languageEnglish
Pages (from-to)575-582
Number of pages8
JournalZoological Science
Issue number5
Publication statusPublished - 2004 May
Externally publishedYes



  • Cerebrospinal fluid-contacting neurons
  • Deep brain photoreceptor
  • Immunohistochemistry
  • Paraventricular organ
  • Photoperiodic-gonadal response

ASJC Scopus subject areas

  • Animal Science and Zoology

Cite this