Hashmi Javeria A, Davis Karen D
Division of Brain, Imaging and Behaviour - Systems Neuroscience, Toronto Western Research Institute, University Health Network, Toronto, Ont., Canada M5T 2S8 Institute of Medical Science, University of Toronto, Canada Department of Surgery, University of Toronto, Canada.
Pain. 2009 Oct;145(3):350-357. doi: 10.1016/j.pain.2009.07.002. Epub 2009 Jul 25.
It is not clear how males and females cope with pain over time and how sensory and emotional qualities fluctuate from moment to moment, although studies of pain at discrete time points suggest that women are more pain sensitive than men. Therefore, we developed a new broader-based pain model that incorporates a temporally continuous assessment of multiple pain dimensions across sensory and affective dimensions, and normalized peak pain intensity to unmask sex differences that may otherwise be confounded by inter-individual variability in pain sensitivity. We obtained continuous ratings of pain, burning, sharp, stinging, cutting, and annoyance evoked by repeated prolonged noxious heat stimuli in 32 subjects. Strikingly, females reported more pain than males at the outset of the first exposure to pain, but then experienced less pain and annoyance than males as a painful stimulus was sustained and with repeated stimulation. Patterns of pain and annoyance attenuation in women resembled the attenuation of sharp, stinging and cutting sensations, whereas patterns of pain and annoyance in men resembled burning sensations. Taken together, these data demonstrate a prominent sex difference in the time course of pain. Notably only females demonstrate adaptation and habituation that allow them to experience less pain over time. These findings suggest a sexual dichotomy in mechanisms underlying pain intensity and annoyance that could involve specific quality-linked mechanisms. Importantly, temporal processing of pain differs between males and females when adjusted for sex differences in pain sensitivity. Our findings provide insight into sex differences in tonic and possibly chronic pains.
目前尚不清楚男性和女性如何长期应对疼痛，以及感觉和情绪特质如何随时间波动，尽管在离散时间点进行的疼痛研究表明女性比男性对疼痛更敏感。因此，我们开发了一种新的更广泛的疼痛模型，该模型纳入了对感觉和情感维度上多个疼痛维度的时间连续评估，并对峰值疼痛强度进行了标准化，以揭示可能因个体疼痛敏感性差异而混淆的性别差异。我们对32名受试者在重复长时间有害热刺激下引起的疼痛、灼痛、刺痛、切割痛和烦恼进行了连续评分。令人惊讶的是，在首次接触疼痛时，女性报告的疼痛比男性多，但随着疼痛刺激的持续和重复刺激，女性随后经历的疼痛和烦恼比男性少。女性的疼痛和烦恼减轻模式类似于尖锐、刺痛和切割感的减轻，而男性的疼痛和烦恼模式类似于灼痛。综上所述，这些数据表明在疼痛的时间进程中存在显著的性别差异。值得注意的是，只有女性表现出适应和习惯化，使她们随着时间的推移经历更少的疼痛。这些发现表明在疼痛强度和烦恼背后的机制存在性别二分法，这可能涉及特定的质量相关机制。重要的是，在调整了疼痛敏感性的性别差异后，男性和女性在疼痛的时间处理上存在差异。我们的发现为紧张性疼痛和可能的慢性疼痛中的性别差异提供了见解。
