鞘内注射P物质拮抗氯胺酮的抗伤害作用

目的观察脊髓P物质对氯胺酮抗伤害作用的影响。方法在小鼠福尔马林实验中,结合行为学和Fos蛋白表达,观察鞘内注射(it)不同剂量的P物质对氯胺酮抗伤害作用的影响。结果氯胺酮20、30mg·kg-1ip可剂量依赖性地减少小鼠舔足时间(P<0.05)。P物质0.25、0.5ngit可增加注射氯胺酮小鼠舔足时间(P<0.05)。小鼠注射福尔马林后,注射侧脊髓背角Fos免疫样(Foslikeimmunoreactive,FLI)阳性神经元数量明显增加(P<0.01),预先给于氯胺酮30mg.kg-1ip可以明显减少脊髓背角FLI阳性神经元数量(P<0.01),而P物质0.5ngit能明显削弱氯胺酮对脊髓背角Fos表达的抑制(P<0.01)。结论鞘内注射P物质能拮抗脊髓水平氯胺酮抗伤害作用。

Effect of spinal substance P on the artinociceptive propoties of ketamine

Aim To investigate the effect of spinal substance P on the antinociceptive propoties of ketamine. Methods Using behaviors and Fos expression technique,the effects of intrathecal administration (it) of substance P of different dose on the ketamine induced antinociception were observed in the formalin test of mice. Results Compared with NS group, the amount of time that mice spent licking the injected paw was dose-dependently decreased in 20 and 30 mg·kg -1 groups(P<0.05). Substance P 0.25,0.5 ng (it) increased the amount of time that ketamine-treated mice spent licking the injected paw(P<0.05). Mice injected with formalin markedly increased the numbers of Fos-like immunoreactive (FLI) positive neurons in the spinal cord ipsilateral to the formalin-injected hind paw(P<0.01),ketamine 30 mg·kg -1 ip significantly decreased the numbers of FLI positive neurons in the spinal cord ipsilateral to the formalin-injected hind paw of mice(P<0.01),but substance P 0.5ng(it)markedly attenuate suppression of Fos activity of spinal cord of ketamine-treated mice(P<0.01). Conclusion Substance P, injected intrathecally, antagonizes the spinal antinociceptive effect of ketamine.