Enhancement of experimental pruritus and mechanically evoked dysesthesiae with local anesthesia.
Enhancement of experimental pruritus and mechanically evoked dysesthesiae with local anesthesia.
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DOI：
10.1080/08990229970357
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发表时间：
1999
影响因子：
0.9
通讯作者：
P. Atanassoff;S. Brull;Jun-Ming Zhang;K. W. Greenquist;David G. Silverman;R. LaMotte
中科院分区：
文献类型：
--
作者：
P. Atanassoff;S. Brull;Jun-Ming Zhang;K. W. Greenquist;David G. Silverman;R. LaMotte
疼痛减轻瘙痒--一种众所周知的抓挠皮肤的效果。组胺引起的实验性瘙痒有时伴有继发性疼痛。本研究探讨了消除这种疼痛的影响，通过局部麻醉，瘙痒和增强机械诱发的瘙痒和疼痛后发生的皮内注射组胺。在10名人类受试者中，前臂掌侧注射20微升2%氯普鲁卡因（实验组）或20微升生理盐水（对照组）。将10微升组胺注射到每个水泡中，并估计所得瘙痒程度。绘制了三个皮肤区域的边界，在这些区域内，对水泡周围皮肤的机械刺激引起异常感觉（感觉迟钝）：感觉异常，定义为无害的抚摸引起的瘙痒，以及痛觉过敏和感觉过敏，其特征分别为用细尖细丝刺破皮肤引起的疼痛增强和瘙痒增强。瘙痒的幅度和持续时间显着更大，感觉迟钝的面积显着更大的实验比对照arm. It假设，存在两类组胺敏感的初级传入神经元。一类是“过敏性”，介导瘙痒，而另一类是“抗过敏性”，引起组胺引起的瘙痒和感觉迟钝的中枢介导的减少。进一步表明，麻醉剂阻断了抗癫痫传入神经的放电，阻止了中枢抑制的发生，从而揭示了抗癫痫传入神经的作用。
Pain reduces itch-a commonly known effect of scratching the skin. Experimentally produced itch from histamine is sometimes accompanied by secondary sensations of pain. The present study investigated the effects of eliminating this pain, by means of a local anesthetic, on the itch and the enhanced mechanically evoked itch and pain that occur after an intradermal injection of histamine. In ten human subjects, the volar forearm was injected with either 20 microl of 2% chloroprocaine (experimental arm), or 20 microl of saline (control arm). Histamine 10 microl was injected into each bleb, and the resulting magnitude of itch estimated. The borders of three cutaneous areas were mapped within which mechanical stimulation of the skin surrounding the bleb elicited abnormal sensations (dysesthesiae): alloknesis, defined as itch evoked by innocuous stroking, and hyperalgesia and hyperknesis, characterized, respectively, by enhanced pain and enhanced itch evoked by pricking the skin with a fine tipped filament. The magnitude and duration of itch were significantly greater and the areas of dysesthesia significantly larger for the experimental than for the control arm. It is hypothesized that there exist two classes of histamine-sensitive primary afferent neurons. One class is "pruritic", and mediates itch whereas the other is "antipruritic", and evokes a centrally mediated reduction in histamine-evoked itch and dysesthesiae. It is further suggested that the anesthetic blocked the discharges of the antipruritic afferents, preventing the central inhibition from occurring and thereby unmasking the effects of the pruritic afferents.