【摘要】 目的:研究内吗啡肽-1(EM-1)的镇痛作用。方法:采用电刺激鼠尾-嘶叫法、扭体法、佐剂性关节炎以及神经源性疼痛等多种疼痛模型,观察腹腔注射EM-1的镇痛作用,并和脊髓蛛网膜下腔注射和侧脑室注射EM-1的镇痛作用进行比较。结果:1)EM-1能剂量依赖地提高大鼠电刺激鼠尾-嘶叫法的痛阈;能抑制醋酸引起的小鼠扭体反应;在佐剂性关节炎所致的炎症性痛觉过敏及坐骨神经部分结扎所引起的神经源性痛觉过敏中,EM-1也有镇痛作用。2)中枢给EM-1的镇痛作用比外周给药出现得较快,而且较强。3)阿片受体拮抗剂纳洛酮能翻转EM-1的镇痛作用;μ-阿片受体选择性拮抗剂cyprodime也能翻转EM-1的镇痛作用;反复给予EM-1,其镇痛效应逐渐减弱,即产生耐受。结论:EM-1具有确切的镇痛作用,其镇痛作用由中枢μ阿片受体介导。更多还原

【Abstract】 AIM: To study the analgesic effect of endomorphin-1 ( EM-1). METHODS: The experiment was performed in rats and mice to study the analgesic effect of intraperi-(oneal ( ip) injection of EM-1 with tail stimulation-vocalization test, writhing test, adjuvant arthritis, and neuropathic pain model and to compare it with the analgesic effects produced by intracerebroventricular ( icv) and intrathecal (it) administrations. RESULTS: 1) EM-1 raised the pain threshold dose-dependently in tail stimulation-vocalization test in rats and inhibited the writhing responses induced by ip acetic acid in mice. EM-1 also decreased the hyperalgesia in both adjuvant arthritis and neuropathic pain model. 2) The analgesic effect induced by central (icv and it) administration of EM-1 was faster and more powerful than that induced by peripheral (ip) administration. 3) The analgesic effect of EM-1 was reversed by naloxone (opioid receptor antagonist) , as well as by cyprodime (μ-opioid receptor selective antagonist). Repeated administrations of EM-1 induced tolerance. CONCLUSION: EM-1 had a definite analgesic effect and the analgesic effect of EM-1 was mediated by central μ-opioid receptor.更多还原