Endocrinological function of tetrodotoxin in the brain of pufferfish

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K06225
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 40040:Aquatic life science-related
• Research Institution: Kitasato University
• Principal Investigator: Amano Masafumi 北里大学, 海洋生命科学部, 教授 (10296428)
• Co-Investigator(Kenkyū-buntansha): 阪倉 良孝 長崎大学, 水産・環境科学総合研究科(水産), 教授 (20325682) ; 高谷 智裕 長崎大学, 水産・環境科学総合研究科(水産), 教授 (90304972) ; 水澤 寛太 北里大学, 海洋生命科学部, 准教授 (70458743)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: フグ毒 / テトロドトキシン / 内分泌系 / 脳ホルモン

Outline of Final Research Achievements

Tetrodotoxin (TTX) is a potent neurotoxin in pufferfish and accumulates in pufferfish through the food chain. TTX was detected by LC/MS/MS method in the brain, liver, skin, and muscle of wild toxic marine pufferfish such as kusafugu, komonfugu, and okinawafugu. However, TTX was under detectable limit in the brain of non-toxic pufferfish such as yoritofugu, thereby indicating that wild toxic marine pufferfish generally accumulate TTX in the brain. TTX administered orally to the juveniles of hatchery-reared, non-toxic torafugu, decreased plasma cortisol concentrations, and mRNA expression of corticotropin-releasing hormone in the brain. Furthermore, under low salinity conditions, TTX administered orally to torafugu stimulated mRNA expression of prolactin-releasing peptide in the brain. In summary, these results indicate that the brain is the major organ accumulating TTX in the wild toxic marine pufferfish and that TTX in the brain regulates endocrinological function in pufferfish.

Free Research Field

水族生理学

Academic Significance and Societal Importance of the Research Achievements

フグ毒は食物連鎖でフグの体内（主に肝臓，皮膚）に蓄積することが知られている．本研究では，天然の有毒フグでは脳にもフグ毒が蓄積していることを明らかにした．さらに，無毒の養殖トラフグ稚魚にフグ毒を餌に混ぜて経口的に投与したところ，フグ毒はストレスに関与する脳内のホルモンの産生を抑制し，結果的に飼育下のストレス軽減に関わることがわかった．以上より，フグ毒はフグの脳内で内分泌系を制御することが示唆された．