title: Gonadotropin-releasing hormone, a neuropeptide of efferent projections to the teleost retina induces light-adaptive spinule formation on horizontal cell dendrites in dark-adapted preparations kept in vitro.
abstract: The teleost retina receives efferent projections from neurons of the nucleus olfactoretinalis at the base of the olfactory bulbs. These fibres contain gonadotropin-releasing hormone (GnRH) immunoreactive material and are presynaptic to retinal dopaminergic interplexiform cells. We have incubated isolated dark-adapted retinae and eyecup preparations of roach with salmon-GnRH and found an increase in horizontal cell spinule numbers to 70% light-adaptive levels. This effect was blocked by addition of haloperidol to the incubation medium suggesting that GnRH acts via stimulation of the dopaminergic interplexiform cells. We conclude that GnRH containing efferent fibres are capable of inducing light-adaptive changes in the retina and discuss their implication in the control of endogenous rhythms.
authors.affiliation: Anatomisches Institut, Eberhard-Karls-Universität, Tübingen, FRG.
authors.forename: U D
authors.initials: UD
authors.lastname: Behrens
authors.forename: R H
authors.initials: RH
authors.lastname: Douglas
authors.forename: H J
authors.initials: HJ
authors.lastname: Wagner
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003530:Cyprinidae / Q000502:physiology*; D003623:Dark Adaptation / Q000502:physiology*; D003712:Dendrites / Q000502:physiology* / Q000648:ultrastructure; D004298:Dopamine / Q000502:physiology; D007987:Gonadotropin-Releasing Hormone / Q000502:physiology*; D006220:Haloperidol / Q000494:pharmacology; D066298:In Vitro Techniques; D008027:Light; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009411:Nerve Endings / Q000187:drug effects / Q000648:ultrastructure; D009476:Neurons, Efferent / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D012160:Retina / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure; D017949:Retinal Cone Photoreceptor Cells / Q000187:drug effects / Q000648:ultrastructure; D014795:Visual Pathways / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure
chemical_list: D007987:Gonadotropin-Releasing Hormone; D006220:Haloperidol; D004298:Dopamine