Older individuals have an elevated risk for chronic pain as half of all individuals over 65 years old have at least one chronic pain condition. Unfortunately, relevant assessment tools and recommendations for chronic pain management targeting older adults are lacking. This study explores changes in response to pain between young (2-3 months old) and geriatric (20-24 months old) ages using mice. Although cutaneous thresholds to brisk stimuli (von Frey and radiant heat assays) were not affected, behavioral responses to tonic stimuli (acetone and capsaicin assays) were more pronounced in geriatric animals. After nerve injury, geriatric mice present an altered neuropathic pain profile with hypersensitivity to mechanical stimuli but not acetone and an impairment in conditioned noxious stimuli avoidance. This altered behavioral response pattern was associated with an abnormal monoaminergic signature in the medial prefrontal cortex, suggesting decreased COMT function. We conclude that young and geriatric mice exhibit different behavioral and physiological responses to the experience of pain, suggesting that knowledge and practices must be adjusted for geriatric populations.

中文翻译：

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小鼠老年疼痛经历：完整的皮肤阈值但改变了对强直性和慢性疼痛的反应

老年人患慢性疼痛的风险较高，因为 65 岁以上的人中有一半至少患有一种慢性疼痛疾病。不幸的是，缺乏针对老年人的慢性疼痛管理的相关评估工具和建议。本研究使用小鼠探索了年轻（2-3 个月大）和老年（20-24 个月大）年龄之间对疼痛的反应变化。尽管对轻快刺激（von Frey 和辐射热测定）的皮肤阈值不受影响，但老年动物对强直刺激（丙酮和辣椒素测定）的行为反应更为明显。神经损伤后，老年小鼠表现出一种改变的神经性疼痛特征，对机械刺激而不是丙酮过敏，并且在避免条件性有害刺激方面受损。这种改变的行为反应模式与内侧前额叶皮层中异常的单胺能信号有关，表明 COMT 功能下降。我们得出结论，年轻和老年小鼠对疼痛经历表现出不同的行为和生理反应，这表明必须针对老年群体调整知识和实践。