Itch mediators, such as histamine, 5-hydroxytryptamine (5-HT), substance P, leukotrienes B4, platelet activating factor, can induce a dose-dependent scratching behavior in rodents.

• 组胺、5-羟色胺、P物质、白三烯B4和血小板激活因子等致痒介质均可使啮齿动物出现剂量依赖性搔抓行为。