鞘内注射士的宁对丙泊酚镇痛作用的影响

Effects of intrathecal administration of strychnine on propofol induced antinociception

目的 探讨脊髓甘氨酸受体与丙泊酚镇痛作用的关系。方法 以热板法和扭体法测小鼠痛阈的变化 ,观察鞘内注射 (it)不同剂量士的宁对丙泊酚小鼠痛阈的影响。结果 丙泊酚 12 5mg·kg-1腹腔注射 (ip)对小鼠热板法痛阈 (painthresholdinhot platetest,HPPT)无影响 (P >0 0 5 ) ,2 5、5 0mg·kg-1可使小鼠HPPT增加 (P <0 0 5 ) ;丙泊酚 5mg·kg-1静脉注射 (iv)对小鼠扭体次数无影响 (P >0 0 5 ) ,7 5、10mg·kg-1iv可使小鼠扭体次数减少 (P <0 0 5 )。士的宁0 2 5 μgit对丙泊酚小鼠 (5 0mg·kg-1,ip)HPPT无影响 (P>0 0 5 ) ;0 5、0 75、1 0 μgit均可减少丙泊酚小鼠的HPPT(P <0 0 5 )。士的宁 0 2 5、0 5、0 75、1 0 μgit对丙泊酚小鼠 (10mg·kg-1,iv)扭体次数均无影响 (P >0 0 5 )。结论 丙泊酚在热板法和扭体法中产生不同的镇痛作用 ,前者可能与脊髓甘氨酸受体有关 。

AIM To investigate the role of spinal glycine receptor in the antinociceptive propoties of propofol. METHODS Hot-plate test and acetic acid-induced writhing test were used to measure the nociceptive thresholds of mice. The effects of intrathecal administration (it) of glycine receptor antagonists-strychnine on the propofol induced antinociception were observed. RESULTS There were no significant changes in the pain threshold in hot-plate test (HPPT) of mice before and after intraperitoneal administration (ip) of 10% intralipid. Compared with intralipid group, propofol 12.5 mg·kg -1 (ip) had no effect on the HPPT of mice (P>0.05),but the HPPT was dose-dependently increased in 25 and 50 mg·kg -1 groups(P<0.05). Compared with intralipid group, propofol 5 mg·kg -1 (intravenous,iv) had no effects on the writhing times of mice; in contrast, propofol 7.5 and 10 mg·kg -1 (iv) decreased the writhing times significantly (P<0.05).Stychnine 0.25 μg (it) had no effect on the HPPT of propofol-treated mice (P>0.05); on the contrary ,strychnine 0.5,0.75,1.0 μg(it) decreased the HPPT of propofol-treated mice as doses increased(P<0.05).No significant differences were observed on the writhing times of propofol-treated mice after strychinine intrathecal administration at different doses,compared with aCSF administered intrathecally in propofol-treated mice (P>0.05). CONCLUSION Propofol can induce antinociception in hot-plate test and acetic acid-induced writhing test of mice. Spinal glycine receptors may play a role in propofol's antinociceptive properties in hot-plate test of mice.