Naliboff Bruce D, Berman Steve, Suyenobu Brandall, Labus Jennifer S, Chang Lin, Stains Jean, Mandelkern Mark A, Mayer Emeran A
Center for Neurovisceral Sciences and Women's Health, Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.
Gastroenterology. 2006 Aug;131(2):352-65. doi: 10.1053/j.gastro.2006.05.014.
BACKGROUND & AIMS: Symptom-related fears and associated hypervigilance toward visceral stimuli may play a role in central pain amplification and irritable bowel syndrome (IBS) pathophysiology. Repeated stimulus exposure leads to decreased salience of threat and reduction of hypervigilance. We sought to evaluate hypervigilance in IBS visceral hypersensitivity and associated brain activity.
Twenty IBS patients (14 female; moderate to severe symptoms) and 14 healthy controls participated in symptom and rectal distention assessments 6 times over 12 months. In a subset of 12 IBS patients, H2 15O-positron emission tomography images were obtained during baseline, rectal distentions, and anticipation of an aversive distention during the first and last session. Statistical parametric mapping (SPM99) was used to identify areas and networks activated during each session as well as those with differential activation across the 2 sessions.
Perceptual ratings of the rectal inflations normalized over 12 months, whereas IBS symptom severity did not. There were no sex-related differences in these response patterns. Stable activation of the central pain matrix was observed over 12 months, and activity in limbic, paralimbic, and pontine regions decreased. During the anticipation condition, there were significant decreases in amygdala, dorsal anterior cingulate cortex, and dorsal brainstem activation at 12 months. Covariance analysis supported the hypothesis of changes in an arousal network including limbic, pontine, and cortical areas underlying the decreased perception seen over the multiple stimulations.
In IBS patients, repeated exposure to experimental aversive visceral stimuli results in the habituation of visceral perception and central arousal, despite stable activation of networks processing visceral pain and its anticipation.
与症状相关的恐惧以及对内脏刺激的相关过度警觉可能在中枢性疼痛放大和肠易激综合征（IBS）的病理生理学中起作用。反复暴露于刺激会导致威胁显著性降低和过度警觉性降低。我们试图评估IBS内脏超敏反应中的过度警觉性及相关脑活动。
20例IBS患者（14例女性；中度至重度症状）和14名健康对照者在12个月内接受了6次症状和直肠扩张评估。在12例IBS患者的一个亚组中，在基线、直肠扩张以及第一次和最后一次评估期间预期厌恶扩张时，获取了H2 15O-正电子发射断层扫描图像。使用统计参数映射（SPM99）来识别每次评估期间激活的区域和网络，以及在两次评估中具有差异激活的区域和网络。
直肠扩张的感知评分在12个月内恢复正常，而IBS症状严重程度未恢复正常。这些反应模式不存在性别相关差异。在12个月内观察到中枢疼痛矩阵的稳定激活，边缘系统、边缘旁系统和脑桥区域的活动减少。在预期状态下，12个月时杏仁核、背侧前扣带回皮质和背侧脑干的激活显著减少。协方差分析支持了觉醒网络变化的假设，该网络包括在多次刺激后观察到的感知降低背后的边缘系统、脑桥和皮质区域。
在IBS患者中，尽管处理内脏疼痛及其预期的网络稳定激活，但反复暴露于实验性厌恶内脏刺激会导致内脏感知和中枢觉醒的习惯化。
