Effects of Morphine and Time of Day on Pain and Beta-Endorphin
Effects of Morphine and Time of Day on Pain and Beta-Endorphin
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DOI：
10.1177/1099800403257166
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发表时间：
2003-10
影响因子：
2.5
通讯作者：
N. Rasmussen;L. Farr
中科院分区：
文献类型：
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作者：
N. Rasmussen;L. Farr
病人在一天中的某些时间比其他时间报告更多的疼痛，部分原因是身体的抑制性疼痛反应的时间变化。吗啡的镇痛效果随一天中的时间而变化，可能是由于药物对血浆β-内啡肽（BE）的抑制或增强作用。本实验旨在研究吗啡对疼痛诱发的BE反应的时间效应。将6组治疗小鼠（注射硫酸吗啡）和6组对照小鼠（注射生理盐水）以4小时间隔暴露于急性疼痛刺激，并收集血液。采用放射免疫法分析血浆BE。对照小鼠表现出强烈的昼夜节律BE反应节律，峰值在0000，最低点在1200，而接受吗啡的小鼠的BE反应则心律失常。接受吗啡的动物耐受伤害性刺激的时间更长，但镇痛随时间而变化。这些结果表明，吗啡消除了对疼痛的节律性BE反应，并且在一天中的所有时间都不能同等地抑制疼痛。吗啡剂量应滴定，以最大限度地发挥内源性疼痛控制系统，同时实现镇痛与减少剂量。
Clients report more pain at some times of day than at others due, in part, to the temporal variation of the body's inhibitory pain response. The analgesic effectiveness of morphine varies with the time of day, perhaps due to the inhibiting or enhancing effects of the drug on plasma beta-endorphin (BE). This experiment was designed to examine the timed effects of morphine on the pain-induced BE response. Six groups of treatment mice (injected with morphine sulfate) and 6 groups of control mice (injected with saline) were exposed to an acute pain stimulus at 4-h intervals, and blood was collected. Plasma BE was analyzed using radioimmunoassay. Control mice showed a robust cir-cadian BE-response rhythm with a peak at 0000 and a nadir at 1200, whereas the BE response of mice that received morphine was arrhythmic. Animals that received morphine tolerated the noxious stimulus longer, but the analgesia varied with time of day. These results indicate that morphine abolishes the rhythmic BE response to pain and does not inhibit pain equally at all times of day. Morphine doses should be titrated to maximize the endogenous pain control system while achieving analgesia with decreased dosages.