Neural circuit mechanisms underlying sex differences in pain perception

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K15345
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 48020:Physiology-related
• Research Institution: Saitama University (2023); Tokyo Women's Medical University (2021-2022)
• Principal Investigator: Kanaya Moeko 埼玉大学, 研究機構, 助教 (00759805)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 性差 / 免疫 / ミクログリア / マウス / 脊髄

Outline of Final Research Achievements

It is known that there are sex differences in the regulation of pain. The pathway for pain transmission include the lateral and medial pain systems, with the latter responsible for the emotional component of pain. The purpose of this study is to elucidate the functional sex differences in immune cells and the effects of sex steroids in male and female mice. The experimental method involved inducing chronic pain in mice after administering sex steroids. Allodynia, which is the perception of non-painful stimuli as pain, was evaluated, and anxiety states were also assessed. As the results, it suggested that both estrogen in female mice and testosterone in male mice are involved in the control of chronic pain. However, it is unlikely that the increase in anxiety states is a primary cause of chronic pain in this model for either sex. Currently, we are analyzing immune related gene expression in brain regions to further investigate the relationship between chronic pain and sex differences.

Free Research Field

神経内分泌学

Academic Significance and Societal Importance of the Research Achievements

痛みの除去や減弱はいつの時代も人類の課題である。痛みの性差の研究においては、従来より雌雄特異的な性ステロイドの影響が調べられていたが、その効果には相反するものも多い。今後の研究の展開として、痛みの伝導路を構成する神経核限定的な性ステロイドの影響を調べる必要がある。現状では、ターゲットとすべき脳領域は確定していないが、本研究で用いた性ステロイドの影響を受ける慢性疼痛モデルを使用してその点を明らかにしていくことが可能であると考えられる。