Tuckett R P, Wei J Y
Brain Res. 1987 Jun 9;413(1):95-103. doi: 10.1016/0006-8993(87)90157-0.
Within the sampled population of cutaneous unmyelinated afferent neurons (n = 94), only the C-polymodal nociceptor population was reactive to the pruritogen cowhage. Of 62 C-polymodal neurons tested, 11 were unresponsive to cowhage. No C-polymodal neurons were more responsive to inactive, than to active, cowhage (n = 17) and all were responsive to mechanical (n = 62) stimuli and noxious heat (n = 24). The range of conduction velocities obtained by single-unit recording techniques was similar to that found by signal averaging the activity from larger strands of nerve. Hence, it is concluded that our recording technique was capable of recording from the smallest afferent fibers in a cutaneous nerve and it was unlikely that we would have missed finding a slowly conducting, pruritus-signaling neuron due to sampling bias. A search of slowly conducting afferents (n = 314) using electrocutaneous stimulation gave no evidence to suggest the existence of an unknown population of unmyelinated fibers that might signal pruritus. A number of alternative mechanisms by which the sensation of itch might be encoded were discussed, the most favored being the activation of a subset of the C-polymodal nociceptive population.
在采样的皮肤无髓传入神经元群体（n = 94）中，只有C类多模式伤害性感受器群体对致痒原刺蒴麻有反应。在测试的62个C类多模式神经元中，11个对刺蒴麻无反应。没有C类多模式神经元对失活的刺蒴麻比对活性刺蒴麻反应更强（n = 17），并且所有神经元都对机械刺激（n = 62）和有害热刺激（n = 24）有反应。通过单单位记录技术获得的传导速度范围与通过对较大神经束的活动进行信号平均所发现的范围相似。因此，可以得出结论，我们的记录技术能够记录皮肤神经中最小的传入纤维，并且由于采样偏差，我们不太可能错过发现一个传导缓慢的瘙痒信号神经元。使用皮肤电刺激对传导缓慢的传入纤维进行搜索（n = 314），没有证据表明存在可能发出瘙痒信号的未知无髓纤维群体。讨论了瘙痒感觉可能被编码的多种替代机制，最受青睐的是激活C类多模式伤害性感受器群体的一个子集。
