氯胺酮的镇痛作用与脊髓NMDA受体的关系

目的观察氯胺酮的镇痛作用与N-甲基-D-天冬氨酸（NMDA）受体的关系,为提高氯胺酮的临床麻醉质量提供依据。方法160只小鼠随机分成扭体法和热板法两大组。每大组再分为两中组：空白组和氯胺酮组。每中组再分为4小组,每组10只。空白组直接分别鞘内注射人工脑脊液或不同浓度的NMDA;氯胺酮组均腹腔注射氯胺酮20mg·kg^-1,5min后分别鞘内注射人工脑脊液或不同浓度的NMDA,在热板、扭体实验中,观察NMDA对氯胺酮热板法痛阈及扭体次数的影响。结果单用NMDA对小鼠热板法痛阈及扭体次数无明显影响。但NMDA可增加氯胺酮小鼠的扭体次数（P〈0.05）,缩短其热板法的痛阈（P〈0.01）。结论NMDA鞘内注射能拮抗氯胺酮的镇痛作用,提示脊髓NMDA受体可能参与氯胺酮的镇痛作用。

The Relationship Between Analgesia Effect of Ketamine and Spinal NMDA Receptors

Aim To explore the relationship between the analgesic effect of Ketamine and NMDA receptors in order to improve the clinical anesthesic effect of Ketamine.Methods 160 mice were randomly divided into 2 groups(hot-plategroup and writhing test group).Each group contained 2 medium groups(comparison group and Ketamine group).Moreover,each medium group contained 4 small groups of 10 mice.The comparison group was intrathecally injected with ACSF or different concentrations of NMDA;the Ketamine group was also intrathecally injec ted with the same substance 5min after injection of Ketamine The effect of NMDA on pain threshold in hot-plate and writhing times in the mice injected with ketamine was observed.Results NMDA didn't affect the pain threshold and the writhing times in hot-plate,but could increase the writhing times(P<0.05)and shorten the pain threshold of the mice injected with Ketamine.Conclusion NMDA intrathecal injection can resist the analgesic effect of Ketamine,and spinal NMDA receptors can mediate the effect of Ketamine.