电针抗胃炎性痛对内脏感觉c-fos及NOS阳性神经元的影响

目的 :探讨大鼠内脏感觉传入系统c fos及NOS阳性神经元在胃炎性痛时的变化和电针抗胃炎性痛对其的影响。方法 :采用免疫组织化学方法和还原型辅酶Ⅱ显色方法 ,显示在生理条件、胃炎性痛及电针抗痛时c fos和NOS阳性神经元在结状神经节 (NG)、背根神经节 (DRG)、脊髓(SC)及孤束核 (NTS)的表达及其变化。结果 :胃炎性痛时大鼠NG、DRG、SC和NTS中NOS阳性成分有明显变化 ,而c fos的变化仅仅出现在NTS。电针抗胃痛时能调整各个部位NOS阳性成分的变化幅度及孤束核c fos的表达量。结论 :①NO可能参与将胃的伤害性信息向中枢传递 ,其上传途径可能主要是伴随迷走神经径路上行到达脑干的内脏感觉通路 ;②依据c fos在NTS和SC中表达的差异 ,推测在脊髓中可能存在着下行抑制性通路 ,在脊髓水平即对传入的内脏伤害性信息进行了整合 ,阻抑信息的上传 ;③电针参与对胃炎性痛的调节与迷走神经通路中的NO能神经有密切的关系。

Changes of c-fos and Nitric Oxide Synthase Activities in the Visceral Afferent Pathway during Gastric Inflammation Pain and following Electroacupuncture

Objective: To investigate changes of activities of c fos and nitric oxide synthase (NOS) in visceral afferent pathway during gastric experimental inflammation pain and following electroacupuncture (EA). Methods: A total of 30 SD rats were evenly randomized into control group, inflammatory pain group (model group) and EA group. Inflammatory pain model was generated by intragastric infusion of formaldehyde plus normal saline. “Zusanli" (ST 36) was punctured and stimulated electrically (1～5 V, 4～16 Hz) for 60 min. Immonohistochemical staining techniques were used to detect the activities of c fos and NOS in the nodose ganglion(NG), dorsal root ganglion(DRG), spinal cord(SC)and the nucleus of the solitary tract(NTS)during gastric inflammation pain and after EA. Results: In comparison with control group, the number of c fos immuno reaction (IR) positive neurons in NTS X of model group and EA group was significantly bigger ( P <0.01); while that of EA group was significantly smaller than that of model group ( P <0.01). No significant changes were found in SC of the 3 groups. The proportions of NOS positive (stronger and moderate positive) neurons of NG and DRG in model group were significantly lower than those of control group ( P <0.01), while those of NOS positive (stronger, moderate and weaker positive) neurons in NG and DRG of EA group were significantly higher than those of model group ( P <0.01). It shows that NO may be involved in the afferent process of gastric pain signals ascending to the brain stem by way of visceral sensory pathway along the vagus nerve, and EA may reduce pain induced expression of NOS and c fos.Conclusion: EA can resist gastric nociceptive stimulation generated increase of NOS and c fos activities. The descending inhibitory pathway existing in the spinal cord may check the ascending transmission of the visceral nociceptive information.