The action of the sexual pehromone on the vomeronasal epithelium of the newt

2022 Fiscal Year Final Research Report

• Project/Area Number: 17K07490
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Animal physiology/Animal behavior
• Research Institution: Nara Medical University
• Principal Investigator: Toyoda Fumiyo 奈良県立医科大学, 医学部, 准教授 (10244708)
• Project Period (FY): 2017-04-01 – 2023-03-31
• Keywords: 性フェロモン / イモリ / プロラクチン / 性ステロイド / アルギニンヴァソトシン / 性行動

Outline of Final Research Achievements

Two steroidal substances, pregnenolone and androstenedione excreted from the male abdominal gland (AG) were revealed to exert a female-attracting activity and a considerable electro-olfactogram (EOG) response in the vomeronasal epithelium in the sexually developed female newts, Cynops pyrrhogaster. When subthreshold amount of the steroids was applied together with female attracting peptide sodefrin secreted from AG, the EOG response was markedly elevated as compared with the response to sodefrin alone.　PRL was known to induce migration to water, in which courtship and oviposition take place. Intracerebroventricular administration of anti-newt prolactin receptor antibody　blocked spontaneously the preference of aquatic over terrestrial habitats, suggesting that endogenous PRL enhances the preference by acting centrally through the PRL receptors localized in the brain area. The exposure of male attracting peptide, imorin, to the newts enhanced the male courtship behavior effectively.

Free Research Field

行動内分泌学

Academic Significance and Societal Importance of the Research Achievements

本研究は我々がアカハライモリで発見した両生類で初の性フェロモン、脊椎動物で初めてのペプチドフェロモンについて、その作用機序を行動学的、電気生理学的、組織学的手法を用いて探った。これまでの我々による生殖行動発現の内分泌調節の詳細な研究成果に基づくと、フェロモン刺激により活性化される神経回路が同時にホルモンにより調整される可能性が考えられる。その神経回路の存在を探り当て、組織・単一ニューロンレベルで解明しようとする研究は本研究をおいて国内外に例を見ない。本研究は、この点において生殖生理学において先駆的な立場にあるといえる。