Elucidation of the neural mechanism of multimodal analgesia in brainstem spinal cord preparations isolated from neonatal rats

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K18478
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 56020:Orthopedics-related
• Research Institution: Showa University
• Principal Investigator: Tsuzawa Kayo 昭和大学, 医学部, 兼任講師 (70796367)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: アセトアミノフェン / カンナビノイド受容体 / 新生児ラット

Outline of Final Research Achievements

We investigated about the analgesic effect of acetaminophen by evaluating the ventral root reflex response induced by stimulation of the dorsal root in in vitro preparations of rat spinal cord. We analyzed the effects of AM404 and cannabinoid receptor antagonist AM251 on reflex responses in lumbar spinal cord preparations from newborn rats and found that the amplitude of the slow ventral root potential after administration of AM404 was not significantly changed, whereas AM251 significantly increased the amplitude. Administration of the cannabinoid receptor 1 agonist WIN55,212-2 did not significantly affect the reflex response. We suggest that endogenous cannabinoids in the spinal cord are involved in the antinociceptive mechanism through suppressive effects.

Free Research Field

神経生理学

Academic Significance and Societal Importance of the Research Achievements

本研究では、ラットの(脳幹－)脊髄標本というin vitro実験系を用いて、下行性疼痛抑制系を含めたアセトアミノフェンの作用機構における、特にカンナビノイド受容体の役割に注目してその役割を明らかにする。この実験系は主に延髄呼吸中枢の研究に使用されてきたが、複雑な機能的神経回路の神経生理学的・神経薬理学的な研究に極めて有用であり，これまで多くの重要な知見が得られている。鎮痛制御の神経機構の解明においても優れた実験モデルとして考えられており、本研究の成果は新しい鎮痛制御系の開発につながることが期待される。