Wahren Lis Karin, Torebjörk Erik, Jörum Ellen
Department of Clinical Neurophysiology, University Hospital, S-751 85 UppsalaSweden.
Pain. 1989 Sep;38(3):313-319. doi: 10.1016/0304-3959(89)90218-2.
Changes in thermal sensibility for warmth, cold, heat pain and cold pain during nerve compression block of impulse conduction in myelinated fibres were studied in 20 healthy subjects. When mainly unmyelinated fibres were conducting, after 30-36 min of nerve compression, the pain threshold, induced by cold stimulation, was shifted towards higher temperatures (from 19.1 degrees C to 22.8 degrees C, mean values). Furthermore, the sensation of cold pain became more unpleasant and had a hot burning rather than a cold quality. These results indicate that a change in central decoding of the afferent input has occurred, possibly due to lack of inhibition normally exerted by concomitant activation of myelinated fibres. Whereas dramatic changes in the sensation of cold pain were observed during the course of nerve compression, no alteration in heat pain threshold was seen. This implies that heat pain threshold in hairy skin is due to activation of C nociceptor fibres without any significant contribution from myelinated nociceptor fibres. Furthermore, no gating from heat-sensitive myelinated fibre input was evident on heat pain threshold.
在20名健康受试者中研究了有髓纤维冲动传导神经压迫阻滞期间热觉（温暖、寒冷）、热痛觉和冷痛觉的变化。当主要是无髓纤维传导时，在神经压迫30 - 36分钟后，冷刺激诱发的疼痛阈值向更高温度偏移（平均值从19.1摄氏度到22.8摄氏度）。此外，冷痛觉变得更令人不适，具有热灼感而非冷感。这些结果表明传入输入的中枢解码发生了变化，可能是由于缺乏有髓纤维同时激活通常所施加的抑制作用。虽然在神经压迫过程中观察到冷痛觉有显著变化，但热痛阈值未见改变。这意味着多毛皮肤的热痛阈值是由于C类伤害性感受器纤维的激活，有髓伤害性感受器纤维没有任何显著贡献。此外，热敏感有髓纤维输入对热痛阈值没有明显的闸门控制作用。
