Studies on olfactory memory molecules to natal stream odors in the brain of salmon

2015 Fiscal Year Final Research Report

• Project/Area Number: 23380106
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Aquatic life science
• Research Institution: Hokkaido University
• Principal Investigator: UEDA Hiroshi 北海道大学, 北方生物圏フィールド科学センター, 特任教授 (00160177)
• Co-Investigator(Kenkyū-buntansha): IIGO Masayuki 宇都宮大学, 農学部, 教授 (10232109) ; AMANO Masafumi 北里大学, 海洋生命科学部, 教授 (10296428)
• Project Period (FY): 2011-04-01 – 2016-03-31
• Keywords: サケ / 母川記銘 / 母川回帰 / 嗅覚記憶 / NMDA受容体 / 甲状腺刺激ホルモン放出ホルモン / 生殖腺刺激ホルモン放出ホルモン / 嗅電図

Outline of Final Research Achievements

Olfactory memory formation during juvenile salmon imprinting migration and retrieval during adult homing migration were investigated. In the brain of hatchery-reared underyearling juvenile chum salmon (Oncorhynchus keta), thyrotropin-releasing hormone (TRH) gene expression increased immediately after release from a hatchery into the natal steam, and the expression of the essential NR1 subunit of the N-methyl-D-aspartate receptor increased during downstream migration. Gene expression of salmon gonadotropin-releasing hormone (sGnRH) and NR1 increased in the adult chum salmon brain during homing from the Bering Sea to the natal hatchery. Thyroid hormone treatment in juveniles enhanced NR1 gene activation, and GnRHa treatment in adults improved stream odor discrimination. Olfactory memory formation during juvenile downstream migration and retrieval during adult homing migration of chum salmon might be controlled by endocrine hormones and could be clarified using NR1 as a molecular marker.

Free Research Field

魚類生理学