Positive emotions and enriched environment reduce pain through the epigenetic modifications in the central nervous system

2014 Fiscal Year Final Research Report

• Project/Area Number: 24390151
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Pain science
• Research Institution: Wakayama Medical University
• Principal Investigator: SENBA Emiko 和歌山県立医科大学, 医学部, 博士研究員 (00135691)
• Co-Investigator(Kenkyū-buntansha): NARITA Minoru 星薬科大学, 薬学部, 教授 (40318613) ; MURAKAMI Kazuo 公益財団法人国際科学振興財団, その他部局等, その他 (70110517) ; HORI Miyo 公益財団法人国際科学振興財団, その他部局等, 研究員 (90399329)
• Co-Investigator(Renkei-kenkyūsha): KAMI Kstsuya 和歌山県立医科大学, 医学部, 博士研究員 (20204612)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 陽性情動 / マイクロアレイ / 扁桃体 / α-受容体 / 神経障害性疼痛 / 運動療法 / エピジェネティクス / 睡眠障害

Outline of Final Research Achievements

The microarray technique revealed that many genes were up- and down-regulated, especially in amygdala after 4 weeks of tickling stimulation. For example, arufa-adrenergic receptor gene and miR-375-3p were changed in the amygdala of isolated rats, while those in tickled rats were restored, indicating that positive emotions elicited by tickling can reduce stress responses. Treadmill running for 5 days after the partial sciatic nerve ligation significantly improved pain behaviors of neuropathic pain model mice. We revealed that epigenetic mechanisms such as acetylation of H3K9 in activated microglia in the dorsal horn are involved in the exercise-induced hypoalgesia. To clarify the role of VTA dopaminergic neurons on pain threshold, we performed an optogenetic assay by injecting AAV-channelrhodopsin-2 into the VTA of cre-tyrosine hydrolase mice. We found that brain reward system plays a role in the regulation of pain threshold in pathological conditions, such as neuropathic pain state.

Free Research Field

神経解剖学、神経科学、疼痛学