Functional interaction of brain-gut hormones on reservoir function of the stomach

2022 Fiscal Year Final Research Report

• Project/Area Number: 18K11099
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 59040:Nutrition science and health science-related
• Research Institution: Okayama University
• Principal Investigator: Kobashi Motoi 岡山大学, 医歯薬学域, 准教授 (80161967)
• Co-Investigator(Kenkyū-buntansha): 島谷 祐一 東京都市大学, 理工学部, 准教授 (20154263) ; 藤田 雅子 岡山大学, 医歯薬学域, 助手 (40156881)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Keywords: オキシトシン / 胃 / 摂食 / 延髄 / 最後野 / 孤束核 / 迷走神経

Outline of Final Research Achievements

The effects of anorectic substances oxytocin on the motility of the stomach were examined using anesthetized rats. The fourth ventricular administration of oxytocin increased intragastric pressure (IGP) in the forestomach. Conversely, the administration of oxytocin suppressed phasic contractions of the distal stomach. The oxytocin response in the forestomach was not observed after bilateral cervical vagotomy. A microinjection of oxytocin into the area postrema (AP) and/or medial nucleus of the nucleus tractus solitarius (mNTS) induced a rapid and large increase in IGP in the forestomach. Prior injection of an oxytocin receptor antagonist into both the AP and mNTS attenuated the oxytocin response. These results indicate that oxytocin acts on the AP and/or mNTS to increase IGP in the forestomach via vagal preganglionic neurons. The oxytocin-response tends to enlarge after the administration of orexin-1 receptor antagonist. Orexin might mediate the oxytocin-response of the forestomach.

Free Research Field

口腔生理学

Academic Significance and Societal Importance of the Research Achievements

本研究で示されたように、食欲抑制物質オキシトシンは胃近位部内圧を上昇させ、遠位部の律動収縮を減弱した。胃の収縮応答におけるこれらの特徴は、食欲抑制物質に共通していると考えられる。過去の嚥下および食欲促進物質投与の研究結果と合わせると、摂食行動の 3 つの相、すなわち、空腹、嚥下、および満腹に沿って変化する胃近位部と遠位部の運動の組み合わせパターンは動物の摂食状態を評価する重要な指標となり、摂食関連ペプチドの機能を判断する重要な指標となりうる。これら基礎的研究結果は、様々な病因で摂食障害を生じている患者の機能を改善するtherapyの開発・評価に役立つ。