Stanfa L C, Dickenson A H
Department of Pharmacology, University College, London, UK.
Neuroreport. 1994 Jan 12;5(4):469-72. doi: 10.1097/00001756-199401120-00025.
The antinociceptive potency of spinal morphine is enhanced in rats after carrageenan-induced inflammation. This electrophysiological study examines whether changes in alpha-2 adrenergic systems are responsible. Dorsal horn nociceptive neurones were recorded under halothane anaesthesia in normal animals and animals with carrageenan inflammation. There was a mild increase in potency of the selective alpha-2 adrenoceptor agonist dexmedetomidine following carrageenan (ED50 = 1 microgram). Intrathecal idazoxan (100 micrograms), an alpha-2 antagonist, produced a significant facilitation of the C-fibre evoked response in carrageenan-treated but not normal animals. However since neither idazoxan (100 micrograms) or atipamezole (50 micrograms, another antagonist) influenced the potency of spinal morphine, the increased alpha-2 adrenergic activity in inflammation does not contribute to the enhanced potency of spinal morphine.
角叉菜胶诱导的炎症反应后，大鼠脊髓吗啡的镇痛效力增强。本电生理研究探讨α-2肾上腺素能系统的变化是否与之有关。在氟烷麻醉下，记录正常动物和角叉菜胶诱导炎症动物的背角伤害性神经元。角叉菜胶处理后，选择性α-2肾上腺素能受体激动剂右美托咪定的效力轻度增加（半数有效量=1微克）。鞘内注射α-2拮抗剂咪唑克生（100微克），在角叉菜胶处理的动物而非正常动物中，显著促进了C纤维诱发反应。然而，由于咪唑克生（100微克）或阿替美唑（50微克，另一种拮抗剂）均未影响脊髓吗啡的效力，因此炎症中α-2肾上腺素能活性增加并非脊髓吗啡效力增强的原因。
