Aviram Joshua, Shochat Tamar, Pud Dorit
Faculty of Social Welfare and Health Sciences, University of Haifa, Haifa, Israel.
Pain Med. 2015 Jun;16(6):1137-44. doi: 10.1111/pme.12665. Epub 2014 Dec 28.
Several physiological processes exhibit 24-hour oscillations termed circadian rhythms. Despite numerous investigations on the circadian dynamics of pain perception, findings related to this issue remain inconsistent. This study aimed to assess the effect of time-of-day on multimodal experimental pain perception in healthy males, including "static" and "dynamic" quantitative sensory tests.
A random order tests were performed in the morning, afternoon and evening.
Forty-eight healthy males (25.9 ± 4.7 years old).
Three different pain modalities i) mechanical (pain threshold, tolerance, and intensity), ii) heat (pain threshold and intensity), iii) cold (pain threshold measured in °C and in seconds and cold pain tolerance and intensity) utilizing nine "static" pain parameters, and two "dynamic" pain paradigms i) temporal summation and ii) conditioned pain modulation were assessed in each session.
Pain scores varied significantly in six pain parameters during the day. Specifically, lower pain scores were found in the morning for cold pain threshold (in seconds and in °C), cold pain intensity, cold pain tolerance, heat pain threshold and intensity. There were no significant diurnal differences in the mechanical evoked pain parameters or in either of the "dynamic" pain paradigms.
Thermal pain scores varies during the day and morning seems to be the time-of-day most insensitive to pain. Also, dynamic tests and the mechanical pain model are not appropriate for detecting diurnal variability in pain. The results of this study may be partially explained by a potential analgesic effect of some hormones known to have diurnal variation (e.g., melatonin and cortisol).
多种生理过程呈现出被称为昼夜节律的24小时振荡。尽管对疼痛感知的昼夜动态进行了大量研究，但与此问题相关的研究结果仍不一致。本研究旨在评估一天中的不同时间对健康男性多模式实验性疼痛感知的影响，包括“静态”和“动态”定量感觉测试。
在上午、下午和晚上进行随机顺序测试。
48名健康男性（25.9±4.7岁）。
在每次测试中，利用九个“静态”疼痛参数评估三种不同的疼痛模式：i）机械性（疼痛阈值、耐受性和强度），ii）热（疼痛阈值和强度），iii）冷（以摄氏度和秒为单位测量的疼痛阈值以及冷痛耐受性和强度），以及两种“动态”疼痛范式：i）时间总和和ii）条件性疼痛调制。
一天中六个疼痛参数的疼痛评分有显著差异。具体而言，上午的冷痛阈值（以秒和摄氏度为单位）、冷痛强度、冷痛耐受性、热痛阈值和强度的疼痛评分较低。机械诱发疼痛参数或任何一种“动态”疼痛范式均无显著的昼夜差异。
热痛评分在一天中有所变化，上午似乎是一天中对疼痛最不敏感的时间。此外，动态测试和机械性疼痛模型不适用于检测疼痛的昼夜变化。本研究结果可能部分归因于某些已知具有昼夜变化的激素（如褪黑素和皮质醇）的潜在镇痛作用。
