Department of Clinical and Experimental Medicine, Translational Research Center for Gastrointestinal Diseases (TARGID), University of Leuven, Belgium Department of Neurosciences, Division of Experimental Neurology, Laboratory for Cognitive Neurology, University of Leuven, Belgium Department of Medical Diagnostic Sciences, Medical Imaging Research Center, University of Leuven, Belgium Department of Medical Diagnostic Sciences, Nuclear Medicine Section, University of Leuven, Belgium Faculty of Pharmaceutical Sciences, Laboratory for Radiopharmacy, University of Leuven, Belgium University Psychiatric Centre, Liaison Psychiatry, University Hospital Gasthuisberg, Leuven, Belgium.
Pain. 2013 Oct;154(10):2072-2077. doi: 10.1016/j.pain.2013.06.026. Epub 2013 Jun 20.
Opioidergic neurotransmission in the central nervous system is involved in somatic pain, but its role in visceral pain remains unknown. We aimed to quantify endogenous opioid release in the brain during sustained painful gastric distension. Therefore, 2 dynamic [11C]carfentanil positron emission tomography scans were performed in 20 healthy subjects during 2 conditions: sustained (20 minutes) painful proximal gastric balloon distension at predetermined individual discomfort threshold (PAIN) and no distension (NO PAIN), in counterbalanced order. Pain levels were assessed during scanning using visual analogue scales and after scanning using the McGill Pain Questionnaire. Emotional state was rated after scanning using the Positive and Negative Affect Schedule. Distribution volume ratios in 21 volumes of interest in the pain matrix were used to quantify endogenous opioid release. During the PAIN compared to the NO PAIN condition, volunteers reported a significantly higher increase in negative affect (5.50±1.29 versus 0.10±1.08, P=.0147) as well as higher pain ratings (sensory: 74.05±9.23 versus 1.50±0.95, P<.0001; affective: 91.42±8.13 versus 4.33±6.56, P<.0001). No difference in endogenous opioid release was demonstrated in any of the volumes of interest. Thus, contrary to its somatic counterpart, no opioid release is detected in the brain during sustained visceral pain, despite similar pain intensities. Endogenous opioids may play a less important role in visceral compared to somatic pain.
中枢神经系统中的阿片能神经传递参与躯体疼痛，但在内脏疼痛中其作用尚不清楚。我们旨在量化持续疼痛性胃扩张期间大脑中内源性阿片释放。因此，在 20 名健康受试者中进行了 2 种动态[11C]carfentanil 正电子发射断层扫描（PET）扫描，在 2 种条件下：在预定的个体不适阈值（PAIN）下持续（20 分钟）进行近端胃球囊扩张（PAIN）和不扩张（NO PAIN），以平衡方式进行。扫描过程中使用视觉模拟量表评估疼痛水平，扫描后使用 McGill 疼痛问卷进行评估。扫描后使用正性和负性情绪量表（PANAS）评估情绪状态。在疼痛矩阵的 21 个感兴趣容积中使用分布容积比来量化内源性阿片释放。与 NO PAIN 条件相比，志愿者在 PAIN 条件下报告的负性情绪明显增加（5.50±1.29 与 0.10±1.08，P=.0147），疼痛评分也更高（感觉：74.05±9.23 与 1.50±0.95，P<.0001；情感：91.42±8.13 与 4.33±6.56，P<.0001）。在任何感兴趣的容积中均未显示内源性阿片释放的差异。因此，与躯体疼痛相反，尽管疼痛强度相似，但在持续内脏疼痛期间大脑中未检测到阿片释放。内源性阿片类物质在内脏疼痛中的作用可能不如躯体疼痛重要。
