OBJECTIVE To investigate the relationship between acupoint sensitization on the body surface and neuronal intrinsic excitability of the medium- and small-size dorsal root ganglion (DRG) neurons from the perspective of ion channel kinetics in mice with gastric ulcer. METHODS Male C57BL/6J mice were randomly divided into control (n=32) and model groups (n=34). The gastric ulcer model was established by injection of 60% glacial acetic acid (0.2 mL/100 g) into the gastric wall muscle layer and submucosa near the pylorus in the minor curvature of the stomach. In contrast, the same dose of normal saline was injected in the same way in the control group. Six days after modeling, Evans blue (EB) solution was injected into the mouse's tail vein for observing the number and distribution of the exudation blue spots on the body surface. Histopathological changes of the gastric tissue were observed by H.E. staining. Then, whole-cell membrane currents and intrinsic excitability of medium- and small-size neurons in the spinal T9-T11 DRGs were measured by in vitro electrophysiology combining with biocytin-ABC method. RESULTS In the control group, EB exudation blue spots were not obvious, while in the model group, the blue spots on the body surface were densely distributed in the area of spinal T9-T11 segments, the epigastric region, and the skin around "Zhongwan" (CV12) and "Huaroumen" (ST24) regions, and near the surgical incision region. Compared with the control group, the model group had a high level of eosinophilic infiltrates in the submucosa of gastric tissues, severe gastric fossa structure damage, gastric fundus gland dilation and other pathological manifestations. The number of exudation blue spots was proportional to the degree of inflammatory reaction in the stomach. In comparison with the control group, the spike discharges of type II of medium-size DRG neurons in T9-T11 segments were decreased, and the current of whole-cell membrane was increased, basic intensity was decreased (P<0.05), discharge frequency and discharge number were increased (P<0.01,P<0.000 1); while the discharges of type I small-size DRG neurons were decreased, those of type II neurons increased, the whole-cell membrane current was decreased, and discharge frequency and discharge number were decreased (P<0.01, P<0.000 1). CONCLUSION Both the medium- and small-size DRG neurons from the spinal T9-T11 segments involve in gastric ulcer-induced acupoint sensitization via their different spike discharge activities. And intrinsic excitability of these DRG neurons can not only dynamically encode the plasticity of acupoint sensitization, but also can help us understand the neural mechanism of acupoint sensitization induced by visceral injury.

中文翻译：

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从背根神经节神经元兴奋性角度研究胃溃疡小鼠穴位致敏机制[J].

目的从离子通道动力学角度探讨胃溃疡小鼠体表穴位致敏与中小背根神经节(DRG)神经元内在兴奋性的关系。方法雄性C57BL/6J小鼠随机分为对照组（n=32）和模型组（n=34）。将60%冰醋酸（0.2 mL/100 g）注射到胃小弯处靠近幽门的胃壁肌层和黏膜下层建立胃溃疡模型。相比之下，对照组以相同的方式注射相同剂量的生理盐水。造模后第6天，将伊文思蓝（EB）溶液注入小鼠尾静脉，观察体表渗出蓝点的数量和分布。HE染色观察胃组织的组织病理学变化。然后，通过体外电生理学结合生物胞素-ABC 方法测量脊髓 T9-T11 DRG 中中小神经元的全细胞膜电流和内在兴奋性。结果对照组EB渗出性蓝斑不明显,而模型组体表蓝斑密集分布于脊柱T9~T11节段、上腹及“中万”周围皮肤。 " (CV12) 和 "花肉门" (ST24) 区域，以及靠近手术切口区域。与对照组相比，模型组胃组织粘膜下层嗜酸性粒细胞大量浸润，胃窝结构严重破坏，胃底腺体扩张等病理表现。渗出蓝点的数量与胃内炎症反应的程度成正比。与对照组比较，T9~T11节段中型DRG神经元II型棘波放电减少，全细胞膜电流增加，基本强度降低（P<0.05），放电频率出院次数增加(P<0.01,P<0.000 1)；I型小型DRG神经元放电减少，II型神经元放电增加，全细胞膜电流降低，放电频率和放电次数减少（P<0.01，P<0.000 1）。结论脊髓T9-T11节段的中小尺寸DRG神经元均通过不同的棘波放电活动参与胃溃疡诱发的穴位致敏。而这些DRG神经元的内在兴奋性不仅可以动态编码穴位致敏的可塑性，还可以帮助我们了解内脏损伤引起穴位致敏的神经机制。