title: Pituitary adenylate cyclase-activating polypeptide regulates brain-derived neurotrophic factor exon IV expression through the VPAC1 receptor in the amphibian melanotrope cell.
abstract: In mammals, pituitary adenylate cyclase-activating polypeptide (PACAP) and its receptors PAC1-R, VPAC1-R, and VPAC2-R play a role in various physiological processes, including proopiomelanocortin (POMC) and brain-derived neurotrophic factor (BDNF) gene expression. We have previously found that PACAP stimulates POMC gene expression, POMC biosynthesis, and alpha-MSH secretion in the melanotrope cell of the amphibian Xenopus laevis. This cell hormonally controls the process of skin color adaptation to background illumination. Here, we have tested the hypothesis that PACAP is involved in the regulation of Xenopus melanotrope cell activity during background adaptation and that part of this regulation is through the control of the expression of autocrine acting BDNF. Using quantitative RT-PCR, we have identified the Xenopus PACAP receptor, VPAC1-R, and show that this receptor in the melanotrope cell is under strong control of the background light condition, whereas expression of PAC1-R was absent from these cells. Moreover, we reveal by quantitative immunocytochemistry that the neural pituitary lobe of white-background adapted frogs possesses a much higher PACAP content than the neural lobe of black-background adapted frogs, providing evidence that PACAP produced in the hypothalamic magnocellular nucleus plays an important role in regulating the activity of Xenopus melanotrope cells during background adaptation. Finally, an in vitro study demonstrates that PACAP stimulates the expression of BDNF transcript IV.
authors.affiliation: Department of Cellular Animal Physiology, Donders Centre for Neuroscience, European Graduate School of Neuroscience, Faculty of Science, Radboud University Nijmegen, 6500 GL Nijmegen, The Netherlands.
authors.forename: Adhanet H
authors.initials: AH
authors.lastname: Kidane
authors.forename: Eric W
authors.initials: EW
authors.lastname: Roubos
authors.forename: Bruce G
authors.initials: BG
authors.lastname: Jenks
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics*; D003001:Cloning, Molecular; D005091:Exons; D005786:Gene Expression Regulation / Q000187:drug effects; D052717:Melanotrophs / Q000378:metabolism*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D014018:Tissue Distribution; D014982:Xenopus laevis / Q000235:genetics*
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D012333:RNA, Messenger; D051238:Receptors, Vasoactive Intestinal Polypeptide, Type I