Role of antipruritus and analgesia through TRPV1 channel

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K09033
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Pain science
• Research Institution: Shimane University
• Principal Investigator: Imamachi Noritaka 島根大学, 学術研究院医学・看護学系, 准教授 (40325048)
• Co-Investigator(Kenkyū-buntansha): 齊藤 洋司 島根大学, 学術研究院医学・看護学系, 教授 (50162243)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: TRPV1 / Itch / Opioid

Outline of Final Research Achievements

TRPV1 not only is activated by multiple stimuli but also is involved with histamine-induced itch.The effects of TRPV1 on morphine-induced itch are unknown.We examined the effects of intrathecal administration of TRPV1 antagonist on morphine-induced itch, body temperature, and antinociception for mice.SB366791 dose-dependently reduced the scratching behavior induced by the administration of morphine. SB366791 and the morphine + SB366791 groups did not manifest an increase in body temperature. Antinociceptive effects were observed to occur dose-dependently for morphine but not for SB366791. Compared with morphine alone, the administration of morphine + SB366791 did not reduce significant antinociceptive effects.We propose that an intrathecal TRPV1 antagonist, SB366791, reduced morphine-induced itch without causing hyperthermia and did not suppress morphine-induced antinociception for mice.

Free Research Field

麻酔科学

Academic Significance and Societal Importance of the Research Achievements

TRPV1拮抗薬は新しい鎮痛薬として期待されてきたが、TRPV1拮抗薬を全身投与すると高体温となるため、現在のところ臨床応用されていない。今回われわれは、極少量のTRPV1拮抗薬を髄腔内に投与する手法で未だに治療法が確立されていないモルヒネによる痒みに有効であるかを調べた。結果として極少量のTRPV1拮抗薬の髄腔内投与であれば高体温を生ずることなくモルヒネの鎮痛効果に影響を与えずにモルヒネによる痒みを抑える可能性を示した。この方法は今後のモルヒネによる痒みを治療する方法の一つとして学術的意義
があると考えられる。