title: Double immunocytochemistry of vasoactive intestinal peptide and cGnRH-I in male quail: photoperiodic effects.
abstract: Reproduction in Japanese quail is primarily regulated by photoperiod. Vasoactive intestinal peptide (VIP) has been suggested as a transducer of environmental information, especially photoperiodic cues, to the hypothalamo-pituitary-gonadal axis. To investigate the possible interaction of VIP and the reproductive (gonadotropin-releasing hormone, GnRH) system, double-immunocytochemical staining for VIP and cGnRH-I was conducted in sexually mature male quail held under a long-day photoperiod (16L:8D; LD) and in sexually quiescent males held under a short-day photoperiod (8L:16D; SD). VIP-immunoreactive (ir) cells were found primarily in three locations: lateral septal organ (LSO) in nucleus accumbens (Ac), ventral hypothalamus, and infundibular area. VIP-ir cells in LSO displayed characteristics typical of cerebrospinal fluid (CSF)-contacting cells, and co-existed with cGnRH-I-ir cells and beaded fibers. In contrast, VIP-ir cells in the infundibular area did not co-exist with cGnRH-I-ir structures. The number of visible VIP-ir cells in the infundibular area of SD males was significantly lower than that of LD males, while the number of visible VIP-ir cells in Ac/LSO was not altered by photoperiod. A cluster of cGnRH-I-ir cells in the caudalmost septal area was heavily innervated by VIP-ir fibers, which appeared to contact cGnRH-I-ir cells directly at this location. Both VIP- and cGnRH-I-ir fibers heavily innervated the external layer of the median eminence (ME). These data suggest that Ac/LSO, the caudalmost septal area, and ME are possible sites of interaction between the VIP and the GnRH systems.
authors.affiliation: Department of Animal Science, University of Nebraska-Lincoln, Lincoln, NE 68583-0908, USA.
authors.forename: R
authors.initials: R
authors.lastname: Teruyama
authors.forename: M M
authors.initials: MM
authors.lastname: Beck
mesh_terms: D000818:Animals; D001921:Brain / Q000033:anatomy & histology / Q000276:immunology / Q000378:metabolism*; D003370:Coturnix / Q000502:physiology*; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000276:immunology* / Q000378:metabolism*; D007031:Hypothalamus / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism*; D007150:Immunohistochemistry; D008027:Light; D008297:Male; D008473:Median Eminence / Q000294:innervation*; D009474:Neurons / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism*; D009714:Nucleus Accumbens / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism*; D017440:Photoperiod; D010904:Pituitary Gland, Posterior / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism*; D012098:Reproduction / Q000502:physiology*; D012741:Sexual Maturation; D013737:Testis / Q000033:anatomy & histology*; D014018:Tissue Distribution / Q000276:immunology*; D014660:Vasoactive Intestinal Peptide / Q000276:immunology* / Q000378:metabolism*
chemical_list: D007987:Gonadotropin-Releasing Hormone; D014660:Vasoactive Intestinal Peptide