摘要
应用角叉菜胶后肢局部致炎作为炎症痛的实验动物模型，通过在细胞内记录技术，观察和分析了猫脊髓背根节Aβ神经元的自发放电特性和诱因。结果表明炎症痛导致猫背根节有自发放电的Aβ神经元数明显增加，并表现为持续高频、簇状和不规则等多种型式的放电；在炎症痛不同时程（4和12h），静息膜电位有一定程度的去极化；大多数有自发放电活动的神经元（91％）对外周机械性刺激表现为兴奋反应，其中有部分神经元（9％）同时具有兴奋性和抑制性感受野。胞体给予TTX能阻断这种自发放电；切断外周神经干能使这种自发放电消失，而切断其背根不影响这种自发放电活动。提示炎症痛猫背根节Aβ神经元的兴奋性增强与炎症部位持续性痛的存在相关，可能是炎症性触诱发痛（Allodynia）形成的基础。
In this experiment inflammation by subcutaneous injection of carrageenan into cat hindpaw was used as an inflammatory pain model. The spontaneous firing of the Ac neuron was analyzed by means of the intracellular recording in dorsal root ganglion (DRG) in normal and inflamed cat. The main findings were as follows. (1)The percentage of number of spontaneous firing neurons was significantly increased in inflamed cat than in normal cat, mainly characterized with long-lasting high frequency discharges,bursting and irregular firings in inflamed cat while in normal cat mainly with low frequency regular firings. (2)The resting membrane potential of the DRG Ac neurons showed the depolarizing response at the different time course arter the injection of carrageenan. (3)The majority of neurons recorded was excited by the mechanical stimulation of receptive field, and some were inhibited. (4)The spontaneous discharges of the Ac neurons were blocked by the administration of TTX (2 mol). (5)These spontaneous firings were also blocked by the cut of the Peripheral nerve innervating the inflammatory tissue, but not affected by the cut of the dorsal roots and its related dorsal roots of the other DRGs. Our results strongly suggest that carrageenan-induced inflammatory pain increased the excitability of the DRG neurons, and that the spontaneous firing of the Ac neurons was originated from the peripheral inflammatory tissue,which could be involved in the allodynia of the inflammatory pain.
关键词
背根神经节
自发放电
炎症痛
触诱发痛
dorsal root ganglion intracellular recording spontaneous firing inflammatory pain carrageenan allodynia
