ALTERED PAIN REGULATORY SYSTEMS IN CHRONIC CLINICAL PAIN

血管相关的抗伤害感受（由内源性阿片类物质介导）是健康个体适应急性疼痛的重要组成部分。先前的研究表明，慢性疼痛患者内源性阿片类物质水平可能存在缺陷，尽管对这些缺陷的功能影响知之甚少。 这项研究将：1）检查慢性疼痛患者的静息血压（BP）、急性疼痛敏感性和临床疼痛之间的关系，以及2）检查疼痛患者和正常人之间的这种BP/疼痛关系的内源性阿片样物质介导程度的差异。 30名慢性疼痛患者和30名健康正常人将接受一次安慰剂下的实验室缺血性疼痛刺激，一次纳洛酮阿片类药物阻断下的实验室缺血性疼痛刺激（随机化，平衡顺序）。 在这两个阶段中，将在静息基线时测定BP，并在整个方案期间定期测定。 疼痛患者还将在给药前后评定其临床疼痛。 与以前的工作一样，预计正常人将显示静息BP和急性疼痛敏感性之间的显著正相关性，这将至少部分地被纳洛酮消除。 疼痛患者预期表现出静息BP与临床疼痛和急性疼痛敏感性之间几乎没有相关性或正相关性，并且对阿片类药物阻滞无反应。

Cardiovascular-related antinociception (mediated by endogenous opioids) is an important component of adaptation to acute pain in healthy individuals. Previous research indicates possible deficits in endogenous opioid levels in chronic pain patients, although little is known about the functional effects of these deficits. This study will: 1) examine the relationship between resting blood pressure (BP), acute pain sensitivity, and clinical pain in chronic pain patients, and 2) examine differences in degree of endogenous opioid mediation of this BP/pain relationship between pain patients and normals. Thirty chronic pain patients and 30 healthy normals will undergo a laboratory ischemic pain stimulus once under placebo and once under opioid blockade with naloxone (randomized, counter-balanced order). In both sessions, BP will be determined at resting baseline, and periodically throughout the protocol. Pain patients will also rate their clinical pain before and after drug administration. As in previous work, it is expected that normals will display a significant positive correlation between resting BP and acute pain sensitivity, which will be at lease partially eliminated by naloxone. Pain patients are expected to demonstrate little correlation or a positive correlation between resting BP, and both clinical pain and acute pain sensitivity, and will be unresponsive to opioid blockade.