Finkel Julia C, Besch Virginia G, Hergen Adrienne, Kakareka John, Pohida Thomas, Melzer Jonathan M, Koziol Deloris, Wesley Robert, Quezado Zenaide M N
Department of Anesthesia and Surgical Services, National Institutes of Health Clinical Center, National Institutes of Health, Bethesda, MD 20892-1512, USA.
Anesthesiology. 2006 Aug;105(2):360-9. doi: 10.1097/00000542-200608000-00020.
Age-related changes in nociception have been extensively studied in the past decades. However, it remains unclear whether in addition to the increased incidence of chronic illness, age-related changes in nociception contribute to increased prevalence of pain in the elderly. Although a great deal of evidence suggests that nociception thresholds increase with aging, other studies yield disparate results. The aim of this investigation was to longitudinally determine the effect of aging on nociception.
The authors developed a nociception assay for mice using electrical stimuli at 2,000, 250, and 5 Hz that reportedly stimulate Abeta, Adelta, and C sensory nerve fibers, respectively. A system was designed to automate a method that elicits and detects pain-avoiding behavior in mice. Using a Latin square design, the authors measured current vocalization thresholds serially over the course of mice's life span.
For 2,000-Hz (Abeta), 250-Hz (Adelta), and 5-Hz (C) electrical stimuli, current vocalization thresholds first decreases and then increases with aging following a U-shaped pattern (P < 0.001). In addition, average current vocalization thresholds at youth and senescence are significantly higher than those at middle age for the 250-Hz (Adelta) and 5-Hz (C fiber) electrical stimulus (P < 0.05).
Using a novel and noninjurious nociception assay, the authors showed that over the life span of mice, current vocalization threshold to electrical stimuli changes in a U-shaped pattern. The findings support the notion that age-related changes in nociception are curvilinear, and to properly study and treat pain, the age of subjects should be considered.
在过去几十年中，已经对伤害感受方面与年龄相关的变化进行了广泛研究。然而，除了慢性病发病率增加之外，伤害感受方面与年龄相关的变化是否导致老年人疼痛患病率增加仍不清楚。尽管大量证据表明伤害感受阈值会随着年龄增长而升高，但其他研究得出了不同的结果。本研究的目的是纵向确定衰老对伤害感受的影响。
作者开发了一种针对小鼠的伤害感受测定方法，使用2000Hz、250Hz和5Hz的电刺激，据报道这些刺激分别刺激Aβ、Aδ和C感觉神经纤维。设计了一个系统来自动化一种引发并检测小鼠疼痛回避行为的方法。作者采用拉丁方设计，在小鼠寿命期间连续测量当前发声阈值。
对于2000Hz（Aβ）、250Hz（Aδ）和5Hz（C）电刺激，当前发声阈值随着衰老呈U形模式先降低后升高（P<0.001）。此外，对于250Hz（Aδ）和5Hz（C纤维）电刺激，青年期和衰老期的平均当前发声阈值显著高于中年期（P<0.05）。
作者使用一种新颖且无损伤的伤害感受测定方法表明，在小鼠寿命期间，对电刺激的当前发声阈值呈U形模式变化。这些发现支持了伤害感受方面与年龄相关的变化是曲线变化的观点，并且为了正确研究和治疗疼痛，应该考虑受试者的年龄。
