Cervero F, Meyer R A, Campbell J N
Department of Neurosurgery, Johns Hopkins University, Baltimore, MDUSA Applied Physics Laboratory, Johns Hopkins University, Baltimore, MDUSA Department of Physiology, University of Bristol Medical School, BristolUK.
Pain. 1994 Jul;58(1):21-28. doi: 10.1016/0304-3959(94)90181-3.
Substantial evidence suggests that the hyperalgesia to mechanical stimuli that occurs in an area of uninjured skin surrounding a site of injury (area of secondary hyperalgesia) arises from activity in low-threshold mechanoreceptors (LTMs). In this study, we have investigated if activity in mechanically sensitive nociceptors also contributes to this secondary hyperalgesia. It is known that all woollen fabrics excite LTMs, but that only the prickly ones activate mechanically sensitive nociceptors. Therefore, we have conducted a psychophysical study using a range of prickly and non-prickly woollen fabrics applied to normal and hyperalgesic skin to assess the roles of LTMs and nociceptors in secondary hyperalgesia. We have studied in 10 normal volunteers the sensations of fabric-evoked prickle and pain in normal and hyperalgesic skin. Secondary hyperalgesia was produced by intradermal injection of capsaicin (25 micrograms) into the volar skin of the forearm. Five woollen fabrics (2 non-prickly, 2 prickly and 1 intermediate) were presented, in a blind manner, to the skin before and after the capsaicin injection. The sensation of fabric-evoked prickle was not changed in hyperalgesic skin. On the other hand, little if any pain was evoked by the fabrics when applied to normal skin, but substantial pain was produced by all fabrics when applied to hyperalgesic skin. The pain ratings were graded with the ratings of prickle so that fabrics that evoked the greatest prickle also evoked significantly more pain. The magnitude of pain increased linearly with prickle sensation; the slope of this regression function increased substantially in hyperalgesic skin.(ABSTRACT TRUNCATED AT 250 WORDS)
大量证据表明，在损伤部位周围未受伤皮肤区域（继发性痛觉过敏区）出现的对机械刺激的痛觉过敏源于低阈值机械感受器（LTMs）的活动。在本研究中，我们调查了机械敏感伤害感受器的活动是否也导致这种继发性痛觉过敏。已知所有羊毛织物都会刺激LTMs，但只有带刺的羊毛织物会激活机械敏感伤害感受器。因此，我们进行了一项心理物理学研究，使用一系列带刺和不带刺的羊毛织物分别应用于正常皮肤和痛觉过敏皮肤，以评估LTMs和伤害感受器在继发性痛觉过敏中的作用。我们研究了10名正常志愿者在正常皮肤和痛觉过敏皮肤中对织物诱发的刺痛和疼痛的感觉。通过将辣椒素（25微克）皮内注射到前臂掌侧皮肤来产生继发性痛觉过敏。在注射辣椒素前后，以盲法将五种羊毛织物（2种不带刺、2种带刺和1种中等程度带刺）分别应用于皮肤。在痛觉过敏皮肤中，织物诱发的刺痛感觉没有改变。另一方面，当应用于正常皮肤时，织物几乎不会引起疼痛，但当应用于痛觉过敏皮肤时，所有织物都会产生明显疼痛。疼痛评分与刺痛评分分级，因此诱发最大刺痛的织物也会引起明显更多的疼痛。疼痛程度随刺痛感觉呈线性增加；这种回归函数的斜率在痛觉过敏皮肤中显著增加。（摘要截短于250字）
