Endogenous Anandamide and Cannabinoid Receptor-2 Contribute to Electroacupuncture Analgesia in Rats
Endogenous Anandamide and Cannabinoid Receptor-2 Contribute to Electroacupuncture Analgesia in Rats
复制标题
内源性 Anandamide 和大麻素受体 2 有助于大鼠电针镇痛
DOI：
10.1016/j.jpain.2008.12.012
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发表时间：
2009-07-01
期刊：
影响因子：
4
通讯作者：
Li, Man
中科院分区：
文献类型：
--
作者：
Chen, Lin;Zhang, Jing;Li, Man
针灸在临床上广泛用于治疗急慢性疼痛，但其作用机制尚不完全清楚。虽然内源性大麻素在动物模型和人类中参与了伤害感觉的调节，但它们在针灸镇痛中的作用尚未得到评估。在本报告中，我们在炎症性疼痛动物模型中确定了电针（EA）对皮肤组织中大麻胺水平的影响以及大麻素CB1和CB2受体在EA镇痛作用中的作用。采用大鼠后爪局部注射完全弗氏佐剂（CFA）诱导炎性疼痛。热痛觉过敏用辐射热刺激测试，机械异常痛用von Frey细丝量化。采用高效液相色谱法测定皮肤组织中黄麻胺的浓度。2 hz和100Hz电激作用于GB30和GB34，可显著降低CFA注射引起的热痛觉过敏和机械异常痛。与假手术组相比，EA显著提高了炎症皮肤组织中anandamide的水平。特异性CB2受体拮抗剂AM630局部预处理可显著减弱EA的抗伤感受作用，而选择性CB1受体拮抗剂AM251对EA的抗伤感受作用无显著影响。这些发现表明，EA增强了内源性anandamide从炎症组织的局部释放。外周CB2受体的激活有助于EA对炎症性疼痛的镇痛作用。观点：本研究表明，电针增加炎症性皮肤组织中anandamide水平，CB2受体参与了电针在炎症性疼痛大鼠模型中的镇痛作用。这一信息提高了我们对针灸镇痛作用机制的理解。(C) 2009年由美国疼痛学会出版
Acupuncture is widely used clinically to treat acute and chronic pain conditions, but the mechanisms underlying its effect are not fully understood. Although endocannabinoids are involved in modulation of nociception in animal models and in humans, their role in acupuncture analgesia has not been assessed. In this report, we determined the effect of electroacupuncture (EA) on the level of anandamide in the skin tissue and the role of cannabinoid CB1 and CB2 receptors in the analgesic effect of EA in an animal model of inflammatory pain. inflammatory pain was induced by local injection of complete Freund's adjuvant (CFA) into the hind paw of rats. Thermal hyperalgesia was tested with a radiant heat stimulus, and mechanical allodynia was quantified with von Frey filaments. The anandamide concentration in the skin tissue was measured by using high-performance liquid chromatography. EA, applied to GB30 and GB34, at 2 and 100Hz significantly reduced thermal hyperalgesia and mechanical allodynia induced by CFA injection. Compared with the sham group, EA significantly increased the anandamide level in the inflamed skin tissue. Local pretreatment with a specific CB2 receptor antagonist, AM630, significantly attenuated the antinociceptive effect of EA. However, the effect of EA was not significantly altered by AM251, a selective CB1 receptor antagonist. These findings suggest that EA potentiates the local release of endogenous anandamide from inflamed tissues. Activation of peripheral CB2 receptors contributes to the analgesic effect of EA on inflammatory pain.Perspective: This study shows that electroacupuncture increases the anandamide level in inflammatory skin tissues, and CB2 receptors contribute to the analgesic effect of electroacupuncture in a rat model of inflammatory pain. This information improves our understanding of the mechanisms involved in the analgesic effect of acupuncture. (C) 2009 by the American Pain Society