Alterations in Endogenous Opioid Functional Measures in Chronic Back Pain
Alterations in Endogenous Opioid Functional Measures in Chronic Back Pain
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DOI：
10.1523/jneurosci.1400-13.2013
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发表时间：
2013-09-11
影响因子：
5.3
通讯作者：
Zubieta, Jon-Kar
中科院分区：
文献类型：
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作者：
Martikainen, Ilkka K.;Pecina, Marta;Zubieta, Jon-Kar
在许多慢性疼痛综合征中缺乏一致的终末器官异常，导致寻找可能解释其临床表现和病程的适应不良的CNS机制。在这里，我们讨论了大脑区域μ阿片受体介导的神经传递，疼痛调节的最佳公认的机制之一，在人类受试者的慢性背痛的作用。我们使用μ阿片受体选择性放射性配体[C-11]卡芬太尼和正电子发射断层扫描，比较了16名慢性非特异性背痛（CNBP）患者和16名年龄和性别匹配的健康对照受试者在基线、疼痛预期期间和中度持续疼痛时体内μ阿片受体的可用性。我们发现CNBP患者的丘脑μ阿片受体可用性基线增加，与先前研究的诊断为纤维肌痛的患者样本相反。在疼痛预期和持续疼痛挑战期间，CNBP患者与其对照样本相比，激活该神经递质系统的能力显示出区域性降低，进一步与临床疼痛和情感状态评级相关。我们的研究结果表明，在不同疼痛条件下，内源性阿片系统功能测量的异质性，以及CNBP中受体可用性和内源性阿片功能的改变与这些患者的临床表现以及阿片类镇痛药对μ阿片受体的影响有关。
The absence of consistent end organ abnormalities in many chronic pain syndromes has led to a search for maladaptive CNS mechanisms that may explain their clinical presentations and course. Here, we addressed the role of brain regional mu-opioid receptor-mediated neurotransmission, one of the best recognized mechanisms of pain regulation, in chronic back pain in human subjects. We compared mu-opioid receptor availability in vivo at baseline, during pain expectation, and with moderate levels of sustained pain in 16 patients with chronic nonspecific back pain (CNBP) and in 16 age- and gender-matched healthy control subjects, using the mu-opioid receptor-selective radioligand [C-11]carfentanil and positron emission tomography. We found that CNBP patients showed baseline increases in thalamic mu-opioid receptor availability, contrary to a previously studied sample of patients diagnosed with fibromyalgia. During both pain expectation and sustained pain challenges, CNBP patients showed regional reductions in the capacity to activate this neurotransmitter system compared with their control sample, further associated with clinical pain and affective state ratings. Our results demonstrate heterogeneity in endogenous opioid system functional measures across pain conditions, and alterations in both receptor availability and endogenous opioid function in CNBP that are relevant to the clinical presentation of these patients and the effects of opioid analgesics on mu-opioid receptors.