Physiological functions of slow muscle-type AChRs of zebrafish

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K15138
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 44050:Animal physiological chemistry, physiology and behavioral biology-related
• Research Institution: Jichi Medical University
• Principal Investigator: ZEMPO Buntaro 自治医科大学, 医学部, 講師 (90758541)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 筋収縮 / ニコチン性アセチルコリン受容体 / ゼブラフィッシュ / 神経筋接合部

Outline of Final Research Achievements

In the present study, we found that the slow muscle-type AChR shows much higher Ca2+ permeability than the fast muscle-type one.To analyze the physiological significance of the Ca2+ influx through AChRs of slow muscles, we generated a transgenic (Tg) zebrafish that expresses Ca2+ impermeable AChRs in its slow muscles. Loss of the Ca2+ permeability markedly decreased locomotor activities at 1-3 days post fertilization (dpf) stages. However, locomotor activities of the Tg line improved during development, and 5dpf Tg showed locomotor activities comparable to zebrafish that express wild-type (WT) AChRs in their slow muscles. These results suggest that Ca2+ influx through AChRs contributes to slow muscle contraction in early developmental stages.

Free Research Field

生理学

Academic Significance and Societal Importance of the Research Achievements

本研究の結果から、遅筋を介したCa2+流入は発生初期の遅筋のCa2+応答の持続に重要であり、これが失われることで運動機能が大きく低下することが示唆された。これにより、遅筋の収縮プロセスにおいてAChRを介したCa2+流入が重要であることが新たにわかった。従来の筋収縮機構のモデルに新たな知見が加わったといえる。遅筋のカルシウム透過性が収縮に重要であるという報告はこれまでにないものであり、筋収縮メカニズムの新たな仕組みの理解に繋がる成果が得られたと言える。