Mohammadian P, Andersen O K, Arendt-Nielsen L
Center for Sensory-Motor-Interaction (SMI), Laboratory for Experimental Pain Research, Aalborg University, Aalborg, Denmark.
Brain Res. 1998 May 4;792(1):1-9. doi: 10.1016/s0006-8993(97)01478-9.
The aim of the present study was to investigate local vascular and sensory changes and their correlation in order to obtain a better understanding of the mechanisms of allodynia, hyperalgesia and vascular changes following tissue inflammation induced by repetitive application of capsaicin cream. This type of application was utilized as a controlled model of inflammation which was altered in intensity due to its repetitive applicability. Ten healthy volunteers participated in two experiments separated by at least five days. Each experiment consisted of a baseline session followed by five additional sessions. Before these sessions either 1.5 g capsaicin (1%) or placebo cream was applied to the volar site of the forearm for 15 min. The areas of stroking allodynia and pin-prick hyperalgesia were mapped and the intensity of spontaneous pain (VAS) was assessed after each application of the cream. In addition, the visible flare, temperature (IR-Thermography), and blood- flow (Laser-Doppler) were measured. The first application of capsaicin was perceived as painful; it induced both secondary hyperalgesia and allodynia. Compared to placebo, the first application of capsaicin cream also resulted in an increased blood-flow, elevated temperature and visible flare. The highest values of these sensory and vascular parameters were reached after the third application. A direct correlation between visible flare, secondary mechanical hyperalgesia and allodynia following repetitive application of capsaicin indicates that both common central and peripheral mechanisms were involved in these changes.
本研究的目的是调查局部血管和感觉变化及其相关性，以便更好地理解反复涂抹辣椒素乳膏诱导组织炎症后发生的异常性疼痛、痛觉过敏和血管变化的机制。这种涂抹方式被用作一种可控的炎症模型，因其可重复性而使炎症强度发生改变。十名健康志愿者参与了两项至少间隔五天的实验。每项实验包括一个基线期，随后还有五个阶段。在这些阶段之前，将1.5克辣椒素（1%）或安慰剂乳膏涂抹在前臂掌侧部位15分钟。在每次涂抹乳膏后，绘制轻触诱发的异常性疼痛区域和针刺诱发的痛觉过敏区域，并评估自发疼痛的强度（视觉模拟评分法）。此外，还测量了可见的红斑、温度（红外热成像）和血流（激光多普勒）。首次涂抹辣椒素时受试者感到疼痛；它诱发了继发性痛觉过敏和异常性疼痛。与安慰剂相比，首次涂抹辣椒素乳膏还导致血流增加、温度升高和可见红斑。在第三次涂抹后，这些感觉和血管参数达到最高值。反复涂抹辣椒素后可见红斑、继发性机械性痛觉过敏和异常性疼痛之间的直接相关性表明，这些变化涉及共同的中枢和外周机制。
