title: Photoperiodic response of serotonin- and galanin-immunoreactive neurons of the paraventricular organ and infundibular nucleus in Japanese quail, Coturnix coturnix japonica.
abstract: 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.
authors.affiliation: Department of Life and Environmental Sciences, Graduate School of Humanities and Sciences, Nara Women's University, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Haida
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Ubuka
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Ukena
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Tsutsui
authors.forename: Tadashi
authors.initials: T
authors.lastname: Oishi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tamotsu
mesh_terms: D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000378:metabolism*; D003370:Coturnix / Q000378:metabolism / Q000502:physiology*; D005455:Fluorescent Antibody Technique; D019004:Galanin / Q000378:metabolism; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism; D018613:Microscopy, Confocal; D008959:Models, Neurological; D009474:Neurons / Q000378:metabolism*; D010286:Paraventricular Hypothalamic Nucleus / Q000378:metabolism*; D017440:Photoperiod; D012701:Serotonin / Q000378:metabolism
chemical_list: D012701:Serotonin; D007987:Gonadotropin-Releasing Hormone; D019004:Galanin