Watanabe S, Kakigi R, Hoshiyama M, Kitamura Y, Koyama S, Shimojo M
Department of Integrative Physiology, National Institute for Physiological Sciences, Aichi, Japan.
J Neurol Sci. 1996 Jan;135(1):68-73. doi: 10.1016/0022-510x(95)00253-x.
By means of somatosensory evoked brain potentials following painful CO2 laser stimulation (pain SEPs) and a pain visual analogue scale (VAS), we investigated changes in pain perception caused by noxious cooling of the skin in normal subjects. Pain SEPs were recorded from scalp electrodes following laser stimulation applied to the leg under various conditions as follows: (1) control (without any interference); (2) 46 degrees C foot (dipping the foot ipsilateral to the stimulated leg in hot water at 46 degrees C); (3) 0 degrees C foot (dipping the foot ipsilateral to the stimulated leg in ice water at 0 degrees C); and (4) 0 degrees C hand (dipping the hand contralateral to the stimulated leg in ice water at 0 degrees C). Marked decreases in amplitude of pain SEPs and VAS were observed under all conditions as compared with the control (P < 0.001); the degree of pain relief was significantly correlated with changes in pain SEPs. These changes were greatest in the '0 degrees C hand' condition, followed in decreasing order by '0 degrees C foot' and '46 degrees C foot', and there was a significant difference between '0 degrees C hand' and the '46 degrees C foot' condition. We considered that the decrease in pain is due to the diffuse noxious inhibitory control (DNIC). The reason why the degree of pain relief in '0 degrees C foot' condition was less than that in '0 degrees C hand' condition is unclear, but some particular spatial summation of two kinds of nociceptive impulses mediated by the same pathway might take place.
通过疼痛性二氧化碳激光刺激后的体感诱发电位（疼痛SEP）和疼痛视觉模拟量表（VAS），我们研究了正常受试者皮肤有害性冷却引起的疼痛感知变化。在以下各种条件下，对腿部进行激光刺激后，从头皮电极记录疼痛SEP：（1）对照（无任何干扰）；（2）46℃足部（将受刺激腿同侧的脚浸入46℃热水中）；（3）0℃足部（将受刺激腿同侧的脚浸入0℃冰水中）；（4）0℃手部（将受刺激腿对侧的手浸入0℃冰水中）。与对照相比，在所有条件下均观察到疼痛SEP和VAS幅度显著降低（P<0.001）；疼痛缓解程度与疼痛SEP的变化显著相关。这些变化在“手部0℃”条件下最大，其次按降序排列为“足部0℃”和“足部46℃”，“手部0℃”和“足部46℃”条件之间存在显著差异。我们认为疼痛减轻是由于弥漫性有害抑制控制（DNIC）。“足部0℃”条件下疼痛缓解程度低于“手部0℃”条件的原因尚不清楚，但可能发生了由同一通路介导的两种伤害性冲动的某种特定空间总和。
