title: Interaction and developmental activation of two neuroendocrine systems that regulate light-mediated skin pigmentation.
abstract: Lower vertebrates use rapid light-regulated changes in skin colour for camouflage (background adaptation) or during circadian variation in irradiance levels. Two neuroendocrine systems, the eye/alpha-melanocyte-stimulating hormone (α-MSH) and the pineal complex/melatonin circuits, regulate the process through their respective dispersion and aggregation of pigment granules (melanosomes) in skin melanophores. During development, Xenopus laevis tadpoles raised on a black background or in the dark perceive less light sensed by the eye and darken in response to increased α-MSH secretion. As embryogenesis proceeds, the pineal complex/melatonin circuit becomes the dominant regulator in the dark and induces lightening of the skin of larvae. The eye/α-MSH circuit continues to mediate darkening of embryos on a black background, but we propose the circuit is shut down in complete darkness in part by melatonin acting on receptors expressed by pituitary cells to inhibit the expression of pomc, the precursor of α-MSH.
authors.affiliation: Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada.
authors.forename: Gabriel E
authors.identifier: 0000-0001-6154-9513
authors.initials: GE
authors.lastname: Bertolesi
authors.affiliation: Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada.
authors.forename: Yi N
authors.initials: YN
authors.lastname: Song
authors.affiliation: Department of Psychology, Mount Royal University, Calgary, AB, Canada.
authors.forename: Karen
authors.initials: K
authors.lastname: Atkinson-Leadbeater
authors.affiliation: Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada.
authors.forename: Jung-Lynn J
authors.initials: JJ
authors.lastname: Yang
authors.affiliation: Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada.
authors.forename: Sarah
authors.initials: S
authors.lastname: McFarlane
mesh_terms: D000818:Animals; D003624:Darkness; D004625:Embryo, Nonmammalian / Q000378:metabolism / Q000528:radiation effects; D047108:Embryonic Development / Q000528:radiation effects; D007700:Kinetics; D007814:Larva / Q000528:radiation effects; D008027:Light; D008547:Melanophores / Q000378:metabolism / Q000528:radiation effects; D008550:Melatonin / Q000378:metabolism; D009490:Neurosecretory Systems / Q000378:metabolism* / Q000528:radiation effects*; D010902:Pituitary Gland / Q000378:metabolism; D011333:Pro-Opiomelanocortin / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012880:Skin Pigmentation / Q000528:radiation effects*; D014982:Xenopus laevis / Q000196:embryology; D000521:alpha-MSH / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D000521:alpha-MSH; D011333:Pro-Opiomelanocortin; D008550:Melatonin
keywords: 
  Xenopus
  ; background adaptation; development; melanophore; pineal gland