Neurology Unit, Ospedale Pediatrico Bambino Gesú, IRCCS, Piazza di Sant'Onofrio, 4, 00165 Rome, Italy; Center for Sensory-Motor Interaction, Aalborg University, Fredrik Bajers Vej 7D-3, 9220 Aalborg, Denmark.
Department of Neurology, Don Carlo Gnocchi Onlus Foundation, Via Alfonso Capecelatro, 66, 20148 Milan, Italy.
Clin Neurophysiol. 2018 May;129(5):920-925. doi: 10.1016/j.clinph.2018.02.004. Epub 2018 Feb 24.
To investigate the mechanism subtending the analgesic effect of high frequency non-painful somatosensory stimulation.
Laser evoked potentials (LEPs) and laser-pain rating were obtained from healthy subjects to stimulation of different parts of the body. LEPs were recorded at baseline and during non-painful electrical stimulation of the superficial branch of the right radial nerve (RRES).
RRES reduced N2/P2 LEP amplitude to right radial (F = 82.4, p < 0.001), left radial (F = 22.2, p < 0.001), and right ulnar (F = 7.2, p = 0.008) stimulation, while the N2/P2 amplitude to left ulnar territory stimulation remained unchanged (F = 3.6, p = 0.07). The laser-pain rating was reduced by RRES to bilateral radial territory stimulation (p < 0.05). In a control experiment, laser-pain rating and LEPs to left foot stimulation were not modified by RRES (p > 0.05).
Our study confirms that the non-nociceptive afferents dampen the nociceptive input. The spatial pattern of this interaction suggests that, when conditioning higher frequency non-painful stimulation is used, the inhibition takes place at the spinal cord.
Our experimental design reproduces what happens when non-painful somatosensory stimuli are used to reduce pain, such as rubbing a wound or during transcutaneous electrical nerve stimulation. Therefore, in these situations the analgesia is likely to occur at the spinal cord level.
探究高频非痛觉躯体感觉刺激产生镇痛作用的机制。
对健康受试者进行激光诱发反应（LEP）和激光疼痛评分，以刺激身体的不同部位。在基线时和对右侧桡神经浅支（RRES）进行无痛电刺激时记录 LEP。
RRES 降低了对右侧桡骨（F=82.4，p<0.001）、左侧桡骨（F=22.2，p<0.001）和右侧尺骨（F=7.2，p=0.008）刺激的 N2/P2 LEP 振幅，而左侧尺骨刺激的 N2/P2 振幅不变（F=3.6，p=0.07）。RRES 降低了双侧桡骨刺激的激光疼痛评分（p<0.05）。在对照实验中，RRES 对左侧足部刺激的激光疼痛评分和 LEP 没有改变（p>0.05）。
本研究证实，非伤害性传入神经抑制伤害性传入。这种相互作用的空间模式表明，当使用条件高频无痛刺激时，抑制发生在脊髓。
我们的实验设计再现了使用非痛觉躯体感觉刺激来减轻疼痛（如摩擦伤口或经皮电神经刺激）时所发生的情况。因此，在这些情况下，疼痛缓解可能发生在脊髓水平。
