Department of Medicine, National University of Singapore, Singapore.
Neurogastroenterol Motil. 2011 Jul;23(7):e261-70. doi: 10.1111/j.1365-2982.2011.01734.x.
Sensory sensitization is one of the main pathophysiological hypotheses in functional gastrointestinal disorders (FGIDs). As sensitization may affect various sensory modalities, we aimed to develop a reproducible gastric pain model utilizing polymodal pathways for use in functional and other pain disorders.
In this double-blind, cross-over study 42 healthy subjects swallowed one capsule containing either capsaicin 0.5mg or nocebo every 15min until moderate pain (intensity >30 on 100mm visual analogue scale) was attained for at least 5min. Pain was rated every minute. Capsaicin titration was repeated thrice for reliability calculation.
Moderate pain in the upper abdomen was successfully achieved in 38 of 42 subjects (90%) with capsaicin titration and in one of 42 (2%) with nocebo. The median dosage required to induce moderate pain for at least 5min was two capsules (interquartile range 1-3) and the median gastric pain intensity was 47 (41-53). The median duration of moderate pain was 8min (5-12). Moderate pain was successfully reproduced with capsaicin in all subjects on study days 2 and 3, with an excellent Cronbach reliability coefficient of >0.8.
CONCLUSIONS & INFERENCES: Standardized gastric pain can be conveniently achieved in a majority of healthy subjects using a simple oral capsaicin titration, with minimal adverse events. The between-test reproducibility is high and nocebo responses are negligible. This technique stimulating a multimodal physiological pathway will be useful in the investigation of sensory changes in FGIDs, including functional dyspepsia.
感觉敏化是功能性胃肠病（FGIDs）的主要病理生理学假说之一。由于敏化可能影响各种感觉模态，我们旨在开发一种利用多模态途径的可重复胃疼痛模型，用于功能性和其他疼痛障碍。
在这项双盲、交叉研究中，42 名健康受试者每隔 15 分钟吞咽一粒含有辣椒素 0.5mg 或安慰剂的胶囊，直到至少 5 分钟出现中度疼痛（强度> 100mm 视觉模拟量表上的 30）。疼痛每一分钟评估一次。重复三次进行辣椒素滴定以计算可靠性。
在 42 名受试者中，有 38 名（90%）成功用辣椒素滴定法和 42 名中的 1 名（2%）用安慰剂滴定法实现了上腹部中度疼痛。诱发至少 5 分钟中度疼痛所需的中位剂量为两粒胶囊（四分位间距 1-3），中位胃疼痛强度为 47（41-53）。中度疼痛的中位持续时间为 8 分钟（5-12）。在研究第 2 和第 3 天，所有受试者均成功用辣椒素重现中度疼痛，Cronbach 可靠性系数>0.8，可靠性高。
使用简单的口服辣椒素滴定法，大多数健康受试者可以方便地获得标准化的胃疼痛，不良反应最小。测试间的重现性很高，安慰剂反应可忽略不计。这种刺激多模态生理途径的技术将有助于研究 FGIDs 中的感觉变化，包括功能性消化不良。
