Center for Neuroplasticity and Pain (CNAP), SMI, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark.
Eur J Pain. 2019 Aug;23(7):1390-1396. doi: 10.1002/ejp.1408. Epub 2019 May 23.
Pro-nociceptive and anti-nociceptive mechanisms are commonly assessed in clinical and experimental pain studies, but their potential interaction is not well understood.
Investigate the effect of conditioning pain modulation (CPM) on temporal summation of pain (TSP).
Twenty healthy participants underwent cuff algometry assessment on the lower legs to establish the pressure pain tolerance threshold (PTT). For the TSP assessment, ten stimuli at the level of the PTT were delivered by computerised cuff inflations (1-s stimulation, 1-s break) while participants rated pain intensity on a 10-cm electronic visual analogue scale (VAS). This TSP paradigm was then repeated with a simultaneous conditioning stimulus induced by a cuff on the contralateral leg, inflated to a constant pressure corresponding to 30% (mild), 70% (moderate) or 100% (severe) of the PTT. These were assessed in a randomised order, with a fifteen-minute break between tests. A final TSP test without conditioning was reassessed at the end (post-recording).
An interaction between stimuli (1-10) and repetition (p < 0.05) was found for VAS scores. VAS scores for the first stimulus were decreased during 30%, 70%, and 100% conditioning intensities, compared to baseline and post-recordings (p < 0.05). There was a significant increase in TSP during conditioning (p < 0.05). There were no significant differences between baseline and post-recordings for any stimuli (p > 0.05).
The current study indicates that mild to severe stimuli administered by cuff algometry does not modulate summation effect of temporal summation of pain, which could indicate that pain facilitatory mechanisms are more potent compared with pain inhibitory mechanisms.
Current knowledge on the interaction effect of pro and anti-nociceptive paradigms are the lacking. The current study indicates that conditioning pain modulation does not modulate the summation effect of temporal summation of pain, when evaluated by computerized pressure algometry. This finding was independent of the mild, moderate and severe painful conditioning intensities.
在临床和实验性疼痛研究中，通常会评估伤害性和抗伤害性机制，但它们之间的潜在相互作用尚不清楚。
研究条件性疼痛调制（CPM）对疼痛时间总和（TSP）的影响。
20 名健康参与者在小腿上进行袖带测痛评估，以确定压力疼痛耐受阈值（PTT）。在 TSP 评估中，通过计算机控制的袖带充气（1 秒刺激，1 秒休息），在参与者的 PTT 水平上施加 10 次刺激，同时他们使用 10 厘米长的电子视觉模拟量表（VAS）评估疼痛强度。然后，在对侧腿部用袖带施加一个恒定压力的同时刺激，该压力对应于 PTT 的 30%（轻度）、70%（中度）或 100%（重度），重复这个 TSP 范式。这些刺激以随机顺序进行评估，两次测试之间休息 15 分钟。在最后（记录后），重新评估没有条件刺激的最终 TSP 测试。
在 VAS 评分中发现了刺激（1-10）和重复（p<0.05）之间的相互作用。与基线和记录后相比，在 30%、70%和 100%的条件强度下，第一个刺激的 VAS 评分降低（p<0.05）。在条件作用期间，TSP 显著增加（p<0.05）。对于任何刺激，在基线和记录后之间都没有显著差异（p>0.05）。
本研究表明，袖带测痛法给予的轻度至重度刺激不会调节疼痛时间总和的总和效应，这可能表明疼痛促进机制比疼痛抑制机制更有效。
目前缺乏关于伤害性和抗伤害性范式相互作用效果的知识。本研究表明，通过计算机化压力测痛评估，条件性疼痛调制不会调节疼痛时间总和的总和效应，无论轻度、中度和重度疼痛的条件强度如何。
