刺激大鼠海马后PAG、NRM和脊髓背角5-HT的变化

目的:探讨刺激大鼠海马后导水管周围灰质(Periaqueductal central gray matter,PAG)、中缝大核(Nucleusraphes magnus,NRM)和脊髓背角5-HT的变化,分析海马在镇痛中的作用机制。方法:健康成年Wistar大鼠40只,随机分为4组。A组:正常对照组;B组:疼痛组;C组:谷氨酸钠组;D组:生理盐水组。四组动物均于2小时后处死,常规灌注冰冻连续切片,采用SABC免疫组化和计算机图像分析技术,检测PAG、NRM5-HT神经元阳性细胞个数及光密度及脊髓背角5-HT阳性纤维及终未的积分光密度等均值。结果:疼痛刺激后,PAG、NRM、脊髓背角内5-HT水平较正常显著增高(P<0.05),谷氨酸钠组则较疼痛组进一步增加。结论:海马兴奋后,激活内源性镇痛系统,使5-HT大量释放,参与镇痛。

Change of PAG, NRM and dosal horn 5-HT after stimulating hippocampus in rats

Objective:To study the changes of 5-HT in (Periaqueductal central gray matter PAG) ,Nucleus raphes maguns in brain stem and drosal horn of spinal cord after stimulation of hippocampus and to investigate the mechanism of hip-pocampal analgesia. Methods ;Fourty adult wistar rats (healthy) were randomly divided into 4 groups:(a)Normal group; (b)Pain group; (c)Sodium glutamate group; (d)Normal saline group. After 2h all rats were executed and perfused. Sections were made for SABC immunohistochemistry,then proceeded by computerized image analyzer. The number and optic densities of 5-HT positive cells were measured. Results: After pain stimulation, the level of 5-HT in PAG and NRM and dorsal horn increased compare with normal level (P<0.05). After injection of sodium glutamate 5-HT positive cells in PAG and NRM obviously increased than that of pain group;5-HT positives fibres and termial at dorsal horn of spinal cord increased. Conclusion: When neurons of hippocampus become excited, the endogenous analgesia system can be activated releasing 5-HT. Hippocampus participates in analgesia.