The effect of maternal experiences on spatial learning and hippocampal neural plasticity

2019 Fiscal Year Final Research Report

• Project/Area Number: 16K08531
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Environmental physiology(including physical medicine and nutritional physiology)
• Research Institution: St. Marianna University School of Medicine
• Principal Investigator: Nagatani Miyako 聖マリアンナ医科大学, 医学部, 准教授 (20450611)
• Co-Investigator(Kenkyū-buntansha): 福島 篤 聖マリアンナ医科大学, 医学部, 講師 (10442716)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: 妊娠 / 出産 / 子育て / 海馬 / AMPA

Outline of Final Research Achievements

To distinguish the role of each maternal event in the development of working memory, we established four experimental groups of nulliparity control, nulliparity with experience of rearing foster pups, primiparity without the rearing experience, and primiparity with all maternal events of pregnancy, delivery, lactation and rearing. Those rats were subjected to the Y-maze test for spatial learning assessments. We then used a protocol to induce LTP by using a whole-cell recording to pair low-frequency synaptic stimulation with a depolarizing voltage-clamp pulse. The present study revealed that primiparity showed a higher % induction of LTP level, RI, AMPA/NMDA ratio and the score of spatial learning than the nullparity control. However, there was no significant difference in the expression of 14-3-3 protein between the four groups. Taken together, reproductive experience could change the subunit composition of synaptic AMPA receptors leading to improved spatial learning.

Free Research Field

行動神経内分泌

Academic Significance and Societal Importance of the Research Achievements

授乳期以降のラットを用いた研究は、報告が少なく、エストロジェン濃度変動に依存しAMPA受容体の構成に変化がみられることから、性周期を明確にした研究を行っている点、AMPA受容体に関する研究は、雄性ラットの研究が主で、経産ラットを用いた研究はないという点から学術的意義がある。生殖イベント全ての経験が顕著に可塑的変化をもたらし、経産ラットの空間学習の成績と海馬内のAMPA受容体のサブユニット構成の変化に14-3-3proteinは関与が低いことを示唆する結果となった。これらの結果は、少子化、子供への虐待問題を抱えている日本では、科学以外の場で注目されることも予想され、社会的にも意義ある研究である。