Elucidation of pathophysiology and development of new treatments for attention deficit hyperactivity disorder focusing on microglia

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K15882
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 52050:Embryonic medicine and pediatrics-related
• Research Institution: Ehime University
• Principal Investigator: Jogamoto Toshihiro 愛媛大学, 医学系研究科, 助教 (10781346)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: ADHD / 豊かな環境 / 最初期遺伝子 / 行動実験 / RNAseq / 養育環境

Outline of Final Research Achievements

Using Lister Hooded Rats (LHRs), we investigated the influence of the parenting environment on ADHD-like behaviors. LHRs (enriched environment group) were reared in an environment equipped with three wooden sheds, a running wheel, and three feeding stations, and the behaviors were compared with those of LHRs (control group) reared in regular cages. In the enriched environment group, the amount of activity decreased significantly on the third day in the open field test. In the control group, on the other hand, the amount of activity increased from the second day onward, and hyperactivity was observed. In a drop test, which measures inattention and impulsivity, those in the enriched environment fell about 10 percent of the time, compared to about 90 percent of those in the control group. It was shown that ADHD-like behaviors were ameliorated by rearing in an enriched environment (Cells 2022, 11, 3649).

Free Research Field

Pediatric Neurology

Academic Significance and Societal Importance of the Research Achievements

豊かな環境での飼育によりADHD様行動が改善し、その改善には前頭葉内側部の神経細胞活動の低下を伴っていることが判明した。しかし、前頭葉内側面は社会性に関わる重要な脳領域であり、この部位の神経細胞活動の低下が真に望ましい変化であるのか疑問が残る。実際、ADHD成人症例での社会的不適応は多動や不注意が問題というより、他者への配慮や他者の気持ちの理解の不足が原因と思われるケースが多い。そこで、毎日愛情を持ってLHRと遊び共に楽しく過ごす時間を持つ「愛情ある飼育(loving rearing; LR)」を行なっている。今後、養育環境における愛情の存在がLHRのADHD様行動を改善するか検討予定である。