Increased placebo analgesia over time in irritable bowel syndrome (IBS) patients is associated with desire and expectation but not endogenous opioid mechanisms
Increased placebo analgesia over time in irritable bowel syndrome (IBS) patients is associated with desire and expectation but not endogenous opioid mechanisms
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DOI：
10.1016/j.pain.2005.03.014
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发表时间：
2005-06-01
期刊：
影响因子：
7.4
通讯作者：
Price, DD
中科院分区：
文献类型：
--
作者：
Vase, L;Robinson, ME;Price, DD
进行了一项研究，以确定预期疼痛水平的变化是否会影响患者缓解疼痛的愿望。或焦虑有助于随着时间的推移增加安慰剂止痛剂，以及确定IBS患者的安慰剂止痛效果是否与内源性阿片类药物机制有关。对2 6例IBS患者进行了直肠刺激(35或55 mm Hg30 S)，并在自然史(NH)、直肠安慰剂(RP)和直肠利多卡因(RL)条件下进行了测试。在所有情况下，16名患者静脉注射生理盐水(以测试安慰剂效应)，10名患者静脉注射纳洛酮(以测试安慰剂效应的纳洛酮拮抗作用)。患者在NH发作后2分钟和22分钟分别对预期疼痛程度、缓解疼痛的愿望和焦虑程度进行评分。反相。和RL条件，他们每隔5分钟评定一次实际疼痛强度，持续40分钟。有一个巨大而显著的安慰剂效应(W<；0.001)，随着时间的推移而增加。预期疼痛水平、对疼痛缓解的渴望和焦虑的评级随着时间的推移而下降，并在最后半个疗程中导致安慰剂和利多卡因反应的更大差异。这些变化表明，负面情绪的减少可能是安慰剂效果的核心。心理调节因子(欲望)之间无显著差异。生理盐水组和纳洛酮组的预期、焦虑)或安慰剂效应，表明在这个临床相关的范例中，心理介质和安慰剂止痛效应都与内源性阿片类药物无关。(C)2005年国际疼痛研究协会。爱思唯尔出版，版权所有。
A study was conducted to determine whether changes in expected pain levels, desire for pain relief. or anxiety contribute to an increase in placebo analgesia over time as well as to determine whether placebo analgesic effects of IBS patients are related to endogenous opioid mechanisms. Twenty-six women with IBS were exposed to rectal stimulation (35 or 55 mmHg for 30 s) and tested under natural history (NH), rectal placebo (RP) and rectal lidocaine (RL) conditions. During all conditions, 16 patients were given saline intravenously (to test for a placebo effect) and 10 patients were given naloxone intravenously (to test naloxone antagonism of the placebo effect) on a double blind basis. Patients rated expected pain level, desire for pain relief and anxiety at 2 and 22 min after the onset of NH. RP. and RL conditions and they rated actual pain intensity at 5-min intervals for 40 min. There was a large and significant placebo effect W < 0.001) that increased over time. Ratings of expected pain levels, desire for pain relief and anxiety decreased over time and contributed to more variance in placebo and lidocaine responses during the last half of the session. These changes suggest that a reduction in negative emotions may be central to placebo effects. There was no significant difference between psychological mediators (desire. expectation, anxiety) or the placebo effect in the saline and naloxone groups, indicating that neither the psychological mediators nor the placebo analgesic effect were associated with endogenous opioids in this clinically related paradigm. (c) 2005 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.