氯胺酮通过NO通路介导的抗伤害作用与抑制脊髓P物质受体研究

目的:观察氯胺酮(Ket)通过一氧化氮(NO)通路介导的抗伤害作用与脊髓P物质(SP)受体的关系及可能机制。方法:通过行为学实验、免疫组织化学技术和分光光度法,记录鞘内注射SP和/或腹腔注射Ket,热板法实验观察小鼠舔后足反应的潜伏期、甲醛实验玉相和域相小鼠舔足时间、脊髓Fos免疫样(FLI)阳性神经元数量和一氧化氮合酶(NOS)活性及NO产量的变化。结果:热板法实验:Ket 20 mg/kg和30 mg/kg腹腔注射可使小鼠热板法痛阈增加(P<0.05~P<0.01),SP 0.5 ng鞘内注射后15 min和20 min均可减少Ket小鼠热板法痛阈(P<0.01和P<0.05)。甲醛实验:Ket 30 mg/kg腹腔注射可减少小鼠舔足时间(P<0.01),鞘内注射SP 0.5 ng可增加Ket小鼠2个时相舔足时间(P<0.01和P<0.05)。对照组小鼠两侧脊髓背角对称分布少量FLI阳性神经元,甲醛注射侧脊髓背角FLI阳性神经元明显高于对照组(P<0.01),腹腔注射Ket显著减少注射侧脊髓背角FLI阳性神经元的数量(P<0.01),而鞘内注射SP可明显对抗Ket对甲醛注射侧脊髓背角FLI阳性神经元的抑制(P<0.01)。Ket均可抑制脊髓NOS活性和NO水平(P<0.05),鞘内注射SP可显著对抗Ket对NOS活性和NO的抑制(P<0.05)。结论:Ket抗伤害作用与抑制脊髓SP受体有关,这可能通过NO通路介导。

Study of the relationship between the antinociception of ketamine mediated by nitric oxide pathway and inhibiting substance P receptors in the spinal cord

Objective:To investigate the relationship between the antinociception of ketamine(Ket) mediated by nitric oxide(NO) pathway and inhibiting substance P ( SP ) receptor in the spinal cord, and its possible mechanism. Methods:The SP of intrathecal injection and/or Ket of intraperitoneal injection were recorded using behavioral experiment, immunohistochemical staining and spectrophotometry. The incubation period of licking foot reaction in mice and licking time in phaseⅠand phaseⅡmice were detected using hot-plate test and using formaldehyde experiment, respectively. The changes of the number of Fos-like immunoreactive ( FLI ) positive cells,nitric oxide synthase ( NOS ) activity and NO content were measured. Results:In hot-plate test, the 20 mg/kg and 30 mg/kg of Ket of intraperitoneal injection could increase the pain threshold in the hot-plate test( HPPT) of mice( P<0. 05 to P<0. 01),the 0. 5 ng of SP of intrathecal injection after 5 min and 20 min could decrease the HPPT of ketamine-treated mice(P<0. 01 and P<0. 05). In formalin test,the 30 mg/kg of Ket of intraperitoneal injection could decrease the licking time of mice(P<0. 01),the 0. 5 ng of SP of intrathecal injection could increase the licking time of mice in two stages(P<0. 05 to P<0. 01). In control group,the few FLI positive cells were symmetrical distribution on both sides of spinal dorsal horn,the FLI positive cells on both sides of spinal dorsal horn injected by formalin were significantly higher than that in control group(P<0. 01). The FLI positive cells on both sides of spinal dorsal horn injected by intraperitoneal Ket significantly decreased(P<0. 01),the 0. 5 ng of SP of intrathecal injection could significantly inhibit FLI positive cells on both sides of spinal dorsal horn injected by formalin(P<0. 01). Ket could inhibit the copy paste in spinal cord(P<0. 05),and the SP of intrathecal injection can counter copy paste caused by Ket(P<0. 05). Conclusions:The antinociception of Ket is correlation with the inhibiting of SP receptor,which may be mediated by NO pathway.