Institute for Environmental and Gender Specific Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Tomioka, Urayasu, Chiba 279-0021, Japan.
Acta Derm Venereol. 2017 Aug 31;97(8):928-933. doi: 10.2340/00015555-2704.
The pathogenesis of psoriatic itch is poorly understood. The aim of this study was to investigate the involvement of opioid receptors in scratching behaviour of imiquimod-induced psoriasis-like dermatitis model mice. Topical application of 5% imiquimod cream to the rostral back skin of mice induced antihistamine-resistant scratching behaviour. The expression of µ-opioid receptor (MOR) protein increased in the epidermis, dorsal root ganglia (DRG) and spinal cord of imiquimod-treated mice. In contrast, the expression of κ-opioid receptor (KOR) protein decreased in the DRG and spinal cord of imiquimod-treated mice, and was undetectable in the epidermis of both groups. Topical or intraperitoneal administration of the MOR antagonist naloxone and oral administration of the centrally acting KOR agonist ICI-199,441 inhibited scratching behaviour, whereas oral administration of the peri-pherally-selective KOR agonist asimadoline did not. These results suggest that peripheral and central MOR and central KOR may be involved in the modulation of scratching behaviour in imiquimod-treated mice.
银屑病瘙痒的发病机制尚不清楚。本研究旨在探讨阿片受体在咪喹莫特诱导的银屑病样皮炎模型小鼠搔抓行为中的作用。将 5%咪喹莫特乳膏涂于小鼠头背部皮肤可诱导抗组胺药抵抗性搔抓行为。咪喹莫特处理组小鼠表皮、背根神经节（DRG）和脊髓中 μ-阿片受体（MOR）蛋白表达增加。相反，咪喹莫特处理组小鼠 DRG 和脊髓中 κ-阿片受体（KOR）蛋白表达减少，两组小鼠表皮均无法检测到 KOR 蛋白表达。MOR 拮抗剂纳洛酮的局部或腹腔给药和中枢作用 KOR 激动剂 ICI-199,441 的口服给药均可抑制搔抓行为，而外周选择性 KOR 激动剂阿斯马多林的口服给药则没有。这些结果表明，外周和中枢 MOR 和中枢 KOR 可能参与了咪喹莫特处理小鼠搔抓行为的调节。
