膈下迷走神经切断术对腹腔注射乙酸致内脏痛大鼠孤束核及胸髓中Fos蛋白表达的影响

目的 探讨迷走神经在内脏痛觉信息传入通路中的作用。方法 将SD大鼠随机分为5组：空白对照组，腹腔注射乙酸刺激组（内脏痛组）、腹腔注射牛理盐水组、迷走神经切断术后＋内脏痛组和假手术后＋内脏痛组（每组6只）。应用免疫组化染色方法，观察各组动物Fos在巾枢延髓孤束核及胸髓的表达。结果 免疫组化染色发现：腹腔注射乙酸刺激组较空白对照组和腹腔注射生理盐水组Fos阳性反应数日在中枢延髓孤束核及胸髓背角浅层表达明显增高；迷走神经切断术后内脏痛组Fos反应数目在孤束核的表达明显减少，而在胸髓背角浅层表达有所增加；假手术后＋内脏痛组与内脏痛组之间Fos表达无明显差异。结论 大鼠腹腔注射乙酸诱发内脏伤害性刺激信息主要是由迷走神经向延髓孤束核传递的，起主导作用；胸髓亦参与了该内脏伤害性刺激的信息传递。

Effects of subdiaphragamatic vagotomy on expression of Fos in the nucleus of the solitary tract and thoracicus spinal cord in visceral pain rats induced by intraperitoneal acetic acid

Objective To investigate the effects of the vagus nerve in afferent input pathway of visceral pain in rats Methods Thirty male SD rats were randomly divided into 5 groups: control group, saline group(NS), visceral pain model group(VP cacatic acid i.p.), subdiaphragamatic vagotomy plus VP group and sham operation plus visceral pain group, and each group has 6 rats. Immono-histochemical methods were used to detect the Fos expression in the nucleus of the solitary tract (NTS) and the Thoracicus spinal cord (TH) of rats.Results Fos-positive neurons were significantly found in NTS of medullary and the superficial layer of spinal cord dorsal horn after acetic acid(i.p.), compared with control group and NS group. Following subdiaphragamatic vagotomy plus acetic acid(i.p.) stimulation, the number of Fos-positive nuclei as greatly decreased in NTS, while the number of nuclei as increased in TH spinal cord. When pretreated with sham operation, there was slightly difference of Fos expression compared with VP group. Conclusion It is concluded that visceral pain input mainly via parasympathetic vagal afferents.