ALTERED PAIN REGULATORY SYSTEMS IN CHRONIC CLINICAL PAIN

心血管相关的抗痛觉作用（由内源性阿片介导）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的内源性阿片水平可能存在缺陷，尽管对这些缺陷的功能影响知之甚少。本研究将：1)研究慢性疼痛患者静息血压（BP）、急性疼痛敏感性和临床疼痛之间的关系；2)研究疼痛患者与正常人在这种血压/疼痛关系中内源性阿片介导程度的差异。30例慢性疼痛患者和30例健康正常人分别接受一次安慰剂组和一次纳洛酮类阿片阻断组的实验室缺血性疼痛刺激（随机、平衡顺序）。在两个疗程中，血压将在静息基线上测定，并在整个治疗过程中定期测定。疼痛患者也会在给药前后评估他们的临床疼痛。与之前的研究一样，我们预计正常患者的静息血压与急性疼痛敏感性之间会显示出显著的正相关，而纳洛酮至少会部分消除这种正相关。预计疼痛患者的静息血压与临床疼痛和急性疼痛敏感性之间的相关性不大或正相关，并且对阿片类药物阻断无反应。

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 normal patients 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.