摘要
目的：进一步研究损伤初级感觉神经元交感感觉偶联作用的神经机制． 方法：利用背根节（ Ｄ Ｒ Ｇ）慢性压迫模型，采用离体灌流 Ｄ Ｒ Ｇ 和单纤维记录神经元的自发放电． 结果：当外源性去甲肾上腺素（ Ｎ Ｅ， １０ μｍ ｏｌ／ Ｌ）浸浴损伤 Ｄ Ｒ Ｇ 时，在９５ 个神经元中有 ８５ 个有自发放电的神经元产生明显反应． ８５ 个神经元中， ４４ 个呈现单纯兴奋效应； ２１ 个表现先兴奋后抑制效应； ６ 个出现兴奋抑制交替振荡现象； １４ 个表现抑制效应． Ｎ Ｅ对损伤神经元的兴奋作用可分别被哌唑嗪（５μｍ ｏｌ／ Ｌ）和育亨宾（１０ μｍ ｏｌ／ Ｌ）部分阻断． 用６羟多巴胺化学性交感神经切断和胍乙啶耗竭交感末梢后， Ｎ Ｅ 对损伤 Ｄ Ｒ Ｇ神经元放电频率最大增加百分数明显增加． 结论：在 Ｄ Ｒ Ｇ 慢性压迫模型上，损伤的 Ｄ Ｒ Ｇ 神经元存在肾上腺素能敏感性；α１ 和 α２ 肾上腺素受体参与兴奋性肾上腺素能敏感性；这种肾上腺素能敏感性不依赖于交感节后神经末梢的存在．
AIM: To further test, with the model of chronic compression of DRG (CCD), the plasticity and neuronal mechanism of sympathetic sensory coupling. METHODS: Spontaneous activity of single fibers was recorded extracellularly in vitro from teased dorsal root A fibers originating from injured neurons. RESULTS: Eighty five out of the 95 DRG neurons with spontaneous activity were adrenosensitive to exogenous norepinephrine (NE,10 μmol/L) applied around the injured DRGs. Among the 85 neurons, 44 showed excitation, 21 excitation followed by suppression, 6 alternation between excitation and suppression and 14 suppression. In addition, adrenosensitivity was observed in 15 silent myelinated fibers from injured DRGs. The excitatory effect of NE was partially blocked by α 1 and α 2 adrenoceptor antagonists yohimbine (10 μmol/L) or prazosin (5 μmol/L) respectively. Following chemical sympathectomy with 6 OHDA and depletion of sympathetic terminals with guanethidine the excitation of NE was significantly augmented. CONCLUSION: Direct injury to DRG neuronal soma will trigger adrenosensitivity and both α 1 and α 2 adrenoceptors were involved in the adrenosensitivity. Adrenosensitivity of injured DRG neurons is not dependent on postganglionic sympathetic terminals.
出处
《第四军医大学学报》
1999年第7期566-569,共4页
Journal of the Fourth Military Medical University
基金
国家自然科学基金
关键词
肾上腺素能
敏感性
背根节
周围神经损伤
adrenosensitivity
spontaneous activity
dorsal root ganglion
peripheral nerve injury
