摘要
为了观察内源性抗伤害性系统在外周炎症诱发的镜像痛中的作用,本研究在大鼠一侧足底皮下注射完全弗氏佐剂(CFA),在损伤位点诱发出持续1～72h的热痛敏和机械性异常痛觉;CFA注射后1～24h在对侧诱发出机械异常痛觉,即镜像痛。为了进一步探讨内源性抗伤害系统对镜像痛的调节作用,用三个剂量(0.2μg,2μg,20μg)的内吗啡肽2(EM2)以及20μg的EM1分别在CFA注射前10min经鞘内给药。结果显示三个剂量的EM2均可明显反转CFA诱发的镜像机械阈值降低,而EM1对此没有作用。上述结果提示来源于内源性抗伤害性系统的EM2,而不是EM1,在脊髓阶段可能对外周组织炎症诱发的镜像机械异常痛觉发挥抑制性作用。
The present investigation was designed to study, whether endogenous antinociceptive system is effective on mirror-image pain induced by peripheral inflammation. After Complete Freund's adjuvant (CFA) was subcutaneously injected into one hindpaw, besides heat hyperalgesia and mechanical allodynia from 1 h to 72 h at the injured site, contralateral mechanical allodynia was also induced at 1 h and significantly lasted for 24 h after injection, which was called mirror-image pain. To explore the effects of endogenous antinociceptive system on mirror-image pain, endomorphin (EM) 2 was intrathecally administered at doses of 0.2 μg, 2 μg, 20 μg and EM1 was given at the maximum dose of 20 μg by the same way, respectively, 10 min prior to CFA injection. The present results showed that three doses of EM2 could reverse the decreased contralateral mechanical threshold from 48.03±9.07 mN (pre-treatment with vehicle) to ~200.49±53.68 mN, 247.63±49.43 mN and 250.57±55.34 mN (pre-treatments with EM2), respectively, but not in a significantly dose-dependent manner. On the other hand, intrathecal pre-treatment with EM1, the contralateral mechanical threshold was 51.24±12.59 mN after CFA injection, which was similar to that pre-treatment with vehicle. It indicates that spinal EM1 did not have remarkable effect on mirror-image pain behavior. The present results provide evidence for that spinal EM2, but not EM1, mainly originated from the endogenous antinociceptive system might play an inhibitory role in mirror-image mechanical allodynia induced by peripheral tissue inflammation.
出处
《神经解剖学杂志》
CAS
CSCD
北大核心
2005年第3期299-304,共6页
Chinese Journal of Neuroanatomy
基金
国家重点基础研究规划"脑功能和重大疾病的基础研究"(G1999054004)
国家自然科学基金(No.30370458)资助项目
关键词
脊髓
内吗啡肽
外周炎症
镜像痛
剂量
内源性抗伤害性系统
mirror-image pain, endomorphin 2, endogenous antinociceptive system, Inflammation pain, rat
