N-甲基-D-天门冬氨酸对大鼠热痛阈的影响

EXPERIMENTAL STUDY ON THE EFFECTS OF INTRATHECAL ADMINISTRATION OF NMDA ON THE HEAT PAIN THRESHOLD IN RATS

目的 :观察鞘内应用N 甲基 D 天门冬氨酸 (NMDA)对大鼠热痛阈的影响。方法 :70只雌性SD大鼠随机分成 7组 ,A组为对照组 ,鞘内注射生理盐水 ,B组、C组、D组和E组分别为鞘内注射不同剂量的NMDA ,F组鞘内注射NMDA受体拮抗剂 5 甲基 二氢 丙环庚烯 亚胺马来酸(MK80 1) ,G组鞘内注射MK80 1,然后再注射NMDA。各组注射的容积均为 10 μl,每组动物在注药前后用热板测定热痛阈 ,并且计算出疼痛指数 (AI)。结果 :鞘内注射NMDA可以引起大鼠的痛阈降低 ,呈剂量依赖性地减小疼痛指数 ,MK80 1可显著地抑制这种变化。结论

Objective: To observe the effect of intrathecal administration of N-methyl-D-aspartic acid (NMDA) on hociceptive heat threshold in rats. Methods: Seventy SD female rats were randomly divided into seven groups with intrathecal administration of different doses of medicine. The rats in Group A received intrathecal injection of nomal saline as control. Different doses of NMDA were injected intrathecally in Group B, C, D and E. Intrathecal administration of MK801, an antagonist of NMDA receptor, was performed in Group F, while NMDA were injected following the intrathecal injection of MK801 in group G. The volume of administration for each group was 10μl. The hociceptive heat thresholds of rats in each group were measured with hot plate both before and after administration, with the analgesia index(AI) calculated. Results: Intrathecal administration of NMDA decreased the hociceptive threshold of rats, inducing the ascendance of analgesia index in a dose-dependent way. MK801 could inhibit such reaction significantly. Conclusion: Spinal NMDA system plays an important role in the development of hyperalgesia in rats.