Willer J C, Roby A, Le Bars D
Brain. 1984 Dec;107 ( Pt 4):1095-112. doi: 10.1093/brain/107.4.1095.
The nociceptive flexion reflex (RIII reflex) and the concurrent subjective pain score elicited by right sural nerve stimulation at random intensities were studied in 10 healthy volunteers. A close relationship was found between the recruitment curves of the reflex and the pain score as a function of stimulus intensity. As a consequence, the threshold of the RIII reflex (Tr) and of pain sensation (Tp) were found to be almost identical (mean: 9.8 and 11.3 mA, respectively). Similarly, the threshold for obtaining a maximal reflex response (Tmr) was found to be very close to that for intolerable pain (Tip): 33.5 and 35.1 mA, respectively. These four parameters were studied before and during the immersion of the left hand into a heated thermoregulated waterbath at various temperatures (from 40 to 47.5 degrees C). While nonnociceptive temperatures (40 to 44 degrees C) were without effect, higher conditioning temperatures induced an increase in the four thresholds. In addition, a highly significant linear relationship was observed between the increase in these thresholds and the intensity of the conditioning stimulus in the 44 to 47.5 degrees C range. These four parameters were also studied before and during three other nociceptive conditioning stimuli: immersion of the left hand into a 6 degrees C waterbath, 10 watts muscular exercise of the left hand performed under ischaemia and a painful (5.5 kg/cm2) pinch applied on the nasal septum. These three conditioning situations induced a very significant increase of the four thresholds considered in this study with the greatest being observed during nociceptive cold applied to the left hand. During all the conditioning situations, variations in Tr and Tp as well as in Tmr and Tip were found to be linearly related. This indicates a close relationship between the effects of the conditioning nociceptive stimuli on the reflex and the related pain sensation. These results suggest that the modulation of pain by heterotopic nociceptive stimuli can be explained at least in part by a depression in the transmission of nociceptive messages at the spinal level. They are discussed with reference to the counterirritation phenomena and common features with 'diffuse noxious inhibitory controls' (DNIC) are underlined.
在10名健康志愿者中，研究了随机强度刺激右侧腓肠神经所诱发的伤害性屈曲反射（RIII反射）及同时出现的主观疼痛评分。发现反射的募集曲线与作为刺激强度函数的疼痛评分之间存在密切关系。因此，发现RIII反射阈值（Tr）和痛觉阈值（Tp）几乎相同（平均值分别为9.8和11.3毫安）。同样，发现获得最大反射反应的阈值（Tmr）与难以忍受的疼痛阈值（Tip）非常接近：分别为33.5和35.1毫安。在左手浸入不同温度（40至47.5摄氏度）的恒温热水浴之前和过程中，对这四个参数进行了研究。当处于非伤害性温度（40至44摄氏度）时无影响，而较高的预处理温度会导致这四个阈值升高。此外，在44至47.5摄氏度范围内，观察到这些阈值的升高与预处理刺激强度之间存在高度显著的线性关系。在另外三种伤害性预处理刺激之前和过程中，也对这四个参数进行了研究：左手浸入6摄氏度的水浴中、左手在缺血状态下进行10瓦的肌肉运动以及对鼻中隔施加疼痛性（5.5千克/平方厘米）挤压。这三种预处理情况导致本研究中所考虑的四个阈值显著升高，其中在左手受到伤害性冷刺激时升高最为明显。在所有预处理情况下，发现Tr和Tp以及Tmr和Tip的变化呈线性相关。这表明预处理伤害性刺激对反射和相关痛觉的影响之间存在密切关系。这些结果表明，异位伤害性刺激对疼痛的调节至少部分可以通过脊髓水平伤害性信息传递的抑制来解释。结合对抗刺激现象对其进行了讨论，并强调了与“弥漫性伤害性抑制控制”（DNIC）的共同特征。
