Rukwied R, Heyer G
Department of Dermatology, University of Erlangen-Nürnberg, Germany.
Arch Dermatol Res. 1998 Apr;290(4):198-204. doi: 10.1007/s004030050290.
We analysed vasoreactions and sensations of atopic eczema (AE) patients and healthy controls after intracutaneous (i.c.) injection of vasoactive intestinal polypeptide (VIP) and acetylcholine (ACh). Blood flow was measured by laser Doppler flowmetry (LDF). Plasma extravasation and flare size were evaluated planimetrically, and sensations were recorded using visual analog scales. Three groups of subjects (controls, AE patients suffering from acute eczema and AE patients during a symptom-free period) were investigated. We administered VIP separately at concentrations of 1.5 x 10(-7), 1.5 x 10(-6) and 1.5 x 10(-5) M and in combination with ACh (5.5 x 10(-6) M) into the volar forearm of the subjects. Both substances led to an increase in LDF measurements and induced a wheal and flare reaction. Blood flow was elevated as a function of dose after a single VIP application in all groups. Compared with healthy controls, a significant increase in blood flow was measured after combined VIP and ACh administration in AE patients suffering from acute AE, whereas flare area and plasma extravasation were significantly reduced after single VIP and combined VIP and ACh injections, respectively. In all groups, VIP induced dose-dependent pruritus. Compared with a control stimulus (0.9% sodium chloride and ACh), combined injections of VIP and ACh had no additional effect on the magnitude of the sensation. In AE patients, the intensity was similar to that experienced by the control subjects, but the quality of sensation was different: ACh induced pain in the control subjects, pruritus in AE patients, and a mixture of pain and itching in AE patients showing no symptoms. Our results suggest that VIP- and ACh-induced skin reactions and the quality of the sensations depend on the activity of the atopic eczema. Confirming our former studies, AE patients develop a different quality of sensation after ACh administration and also after administration of VIP combined with ACh. Therefore, we suggest that ACh might be involved in the pathomechanisms of pruritus in AE.
我们分析了特应性皮炎（AE）患者和健康对照者在皮内（i.c.）注射血管活性肠肽（VIP）和乙酰胆碱（ACh）后的血管反应和感觉。通过激光多普勒血流仪（LDF）测量血流量。采用平面测量法评估血浆外渗和红斑大小，并使用视觉模拟量表记录感觉。对三组受试者（对照组、患有急性湿疹的AE患者和无症状期的AE患者）进行了研究。我们将浓度分别为1.5×10⁻⁷、1.5×10⁻⁶和1.5×10⁻⁵ M的VIP单独以及与ACh（5.5×10⁻⁶ M）联合注射到受试者的掌侧前臂。两种物质均导致LDF测量值增加，并诱发风团和红斑反应。在所有组中，单次注射VIP后血流量随剂量增加而升高。与健康对照相比，在患有急性AE的AE患者中，联合注射VIP和ACh后测量到血流量显著增加，而单次注射VIP以及联合注射VIP和ACh后，红斑面积和血浆外渗分别显著减少。在所有组中，VIP均诱发剂量依赖性瘙痒。与对照刺激（0.9%氯化钠和ACh）相比，联合注射VIP和ACh对感觉强度没有额外影响。在AE患者中，强度与对照受试者相似，但感觉性质不同：ACh在对照受试者中诱发疼痛，在AE患者中诱发瘙痒，而在无症状的AE患者中诱发疼痛和瘙痒的混合感觉。我们的结果表明，VIP和ACh诱导的皮肤反应以及感觉性质取决于特应性皮炎的活动情况。证实我们之前的研究，AE患者在注射ACh后以及注射VIP与ACh联合制剂后会产生不同性质的感觉。因此，我们认为ACh可能参与了AE瘙痒的发病机制。
