MELATONIN REGULATES DIURNAL CHANGES IN LOCOMOTOR ACTIVITY BY REGULATING 7alpha-HYDROXYPREGNENOLONE SYNTHESIS IN NEWTS

Abstract

Event Abstract Back to Event MELATONIN REGULATES DIURNAL CHANGES IN LOCOMOTOR ACTIVITY BY REGULATING 7alpha-HYDROXYPREGNENOLONE SYNTHESIS IN NEWTS Shogo Haraguchi1, 2, Teppei Koyama1, Kazuyoshi Tsutsui1* and Hubert Vaudry3 1 Waseda University, Department of Biology, Japan 2 Tokyo Gakugei University, Department of Biology, Faculty of Education, Japan 3 University of Rouen, European Institute for Peptide Research, France Steroids can be synthesized de novo in the central and peripheral nervous systems and such steroids are called “neurosteroids”. Seasonally breeding wild animals, such as amphibians, have served as excellent animal models to investigate the biosynthesis and biological actions of neurosteroids. Our previous studies have demonstrated that the brain of amphibians possesses the key steroidogenic enzymes and produces pregnenolone, a precursor of steroid hormones, and other various neurosteroids. We recently found that the brain of seasonally breeding newts actively produces 7alpha-hydroxypregnenolone, a previously undescribed amphibian neurosteroid. Interestingly, this novel neurosteroid acts as a neuronal modulator to stimulate locomotor activity in male newts. Because male newts show marked diurnal changes in locomotor activity, we hypothesized that 7alpha-hydroxypregnenolone may be a key factor for the induction of diurnal changes in locomotor activity in male newts. In this study, we first found diurnal changes in 7alpha-hydroxypregnenolone synthesis in the brain of male newts. The production of 7alpha-hydroxypregnenolone in the male brain increased during the dark phase when locomotor activity of males was high. Thus, diurnal changes in 7alpha-hydroxypregnenolone synthesis in the brain paralleled with locomotor activity in male newts. We then identified melatonin as a key component of the mechanism regulating 7alpha-hydroxypregnenolone synthesis. Decreased synthesis of 7alpha-hydroxypregnenolone occurred in males in vivo after melatonin removal via pinealectomy and orbital enucleation (Px plus Ex). Conversely, increased synthesis of this neurosteroid occurred after melatonin administration to Px plus Ex males. This study demonstrates that melatonin regulates synthesis of 7alpha-hydroxypregnenolone, a key factor for induction of locomotor activity, thus inducing diurnal locomotor changes in male newts Acknowledgements This work was supported by Grants-in-Aid for Scientific Research from the Ministry of Education, Science and Culture, Japan to KT and a Japan Society for the Promotion of Science (JSPS) – Institut National de la Santé de la Recherche Médicale (INSERM) exchange program to KT and HV. Keywords: 7alpha-Hydroxypregnenolone, diurnal changes, locomotor activity, Melatonin, Neurosteroids, newt brain Conference: NASCE 2011: The inaugural meeting of the North American Society for Comparative Endocrinology, Ann Arbor, United States, 13 Jul - 16 Jul, 2011. Presentation Type: Poster Topic: Brain and behavior Citation: Haraguchi S, Koyama T, Tsutsui K and Vaudry H (2011). MELATONIN REGULATES DIURNAL CHANGES IN LOCOMOTOR ACTIVITY BY REGULATING 7alpha-HYDROXYPREGNENOLONE SYNTHESIS IN NEWTS. Front. Endocrinol. Conference Abstract: NASCE 2011: The inaugural meeting of the North American Society for Comparative Endocrinology. doi: 10.3389/conf.fendo.2011.04.00021 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 06 Jul 2011; Published Online: 09 Aug 2011. * Correspondence: Prof. Kazuyoshi Tsutsui, Waseda University, Department of Biology, Tokyo, 162-8480, Japan, k-tsutsui@waseda.jp Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Shogo Haraguchi Teppei Koyama Kazuyoshi Tsutsui Hubert Vaudry Google Shogo Haraguchi Teppei Koyama Kazuyoshi Tsutsui Hubert Vaudry Google Scholar Shogo Haraguchi Teppei Koyama Kazuyoshi Tsutsui Hubert Vaudry PubMed Shogo Haraguchi Teppei Koyama Kazuyoshi Tsutsui Hubert Vaudry Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.