Sarlani Eleni, Grace Edward G, Reynolds Mark A, Greenspan Joel D
University of Maryland Dental School, Baltimore, MD, USA.
Pain. 2004 May;109(1-2):115-23. doi: 10.1016/j.pain.2004.01.019.
Several studies demonstrate that women are more sensitive to experimental pain than men. In addition, women exhibit greater temporal summation of heat and mechanically evoked pain. Since temporal summation of pain is centrally mediated, its greater expression in women suggests a central nociceptive hyperexcitability relative to men. The purpose of this study was to pursue this theory, by further assessing sex differences in (1) temporal summation of mechanically evoked pain, and (2) aftersensations following repetitive noxious stimulation. Sixteen series of 10 repetitive, mildly noxious, mechanical stimuli were applied to the fingers of 25 women and 25 age-matched men. The subjects rated the pain intensity and unpleasantness caused by the first, fifth and tenth stimulus in the series, as well as their aftersensations 15 s and 1 min following the end of stimulation. Data were analyzed by three-way repeated-measures analysis of variance. Pain and unpleasantness ratings increased with repetition of stimulation (P<0.0001). Temporal summation of pain intensity and unpleasantness ratings were more pronounced in women than men (P<0.0001). In addition, significant temporal summation occurred only with 2 s interstimulus interval for men (P<0.0005) but with 2 and 5 s interstimulus interval for women (P<0.0001). Moreover, women provided greater ratings for the intensity and the unpleasantness of aftersensations (P<0.0005) and reported painful aftersensations at greater frequency (P<0.05) Greater temporal summation of pain and aftersensations in women suggests that their central processing of nociceptive input may be more easily upregulated into pathological hyperexcitability, possibly accounting for the higher prevalence of various chronic pain conditions among women.
多项研究表明,女性对实验性疼痛比男性更敏感。此外,女性在热痛和机械诱发疼痛的时间总和方面表现得更为明显。由于疼痛的时间总和是由中枢介导的,其在女性中更明显的表现表明相对于男性,女性存在中枢伤害性超兴奋性。本研究的目的是通过进一步评估(1)机械诱发疼痛的时间总和以及(2)重复性有害刺激后的后感觉中的性别差异来探究这一理论。对25名女性和25名年龄匹配的男性的手指施加了16组,每组10次重复性轻度有害机械刺激。受试者对每组中的第一次、第五次和第十次刺激所引起的疼痛强度和不愉快程度进行评分,以及在刺激结束后15秒和1分钟时对其后感觉进行评分。数据通过三因素重复测量方差分析进行分析。疼痛和不愉快评分随着刺激的重复而增加(P<0.0001)。女性在疼痛强度和不愉快评分的时间总和方面比男性更明显(P<0.0001)。此外,男性仅在刺激间隔为2秒时出现显著的时间总和(P<0.0005),而女性在刺激间隔为2秒和5秒时均出现显著的时间总和(P<0.0001)。此外,女性对后感觉的强度和不愉快程度给出了更高的评分(P<0.0005),并且报告疼痛后感觉的频率更高(P<0.05)。女性疼痛和后感觉的时间总和更明显,这表明她们对伤害性输入的中枢处理可能更容易上调为病理性超兴奋性,这可能解释了女性中各种慢性疼痛状况的患病率较高的原因。