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离体运动神经元对腹外侧索刺激的突触反应特征

汪萌芽, 沈锷

皖南医学院细胞电生理研究室. 上海, 芜湖 241001；中国科学院上海脑研究所. 上海 200031

摘要

应用新生大鼠脊髓薄片运动神经元(MN)细胞内记录技术，对电刺激腹外侧索(VLF)诱发的突触反应进行了电生理特征分析。结果在28个测试的MN中，22个(80％)有兴奋性突触后电位(VLF-EPSP)反应，其中2个跟随在抑制性突触反应之后，6个还对单或串刺激产生慢EPSP反应；VLF－EPSP的潜伏期频数分布呈峰坡性偏态；同-MN的VLF－EPSP与腹根EPSP间有典型的空间总和。VLF－EPSP的幅度随膜超极化而增大，随膜去极化而减小，但背根或腹根刺激诱发的EPSP幅度在膜电位改变时无明显变化。提示VLF中的下行纤维可能与MN的胞体或近端树突形成突触，而背根或腹根中传入纤维与MN的远端树突联系。药理学分析表明，VLF－EPSP可能是由谷氨酸主要激活非NMDA受体而介导的。

关键词： 运动神经元; 兴奋性突触后电位; 下行激活; 腹外侧索; 脊髓; 大鼠

Characteristics of synaptic responses of motoneurons to ventrolateral funiculus stimulation in vitro

Wang Mengya, Shen E

Cell Electrophysiology Laboratory, Wannan Medical College. Wuhu 241001, Shanghai, China；Shanghai Brain Research Institute, Chinese Academy of Science. Shanghai 200031, China

Abstract

By using the intracellular recording techniques, the electrophysiological character-istics of fast excitatory postsynaptic potentials (EPSP) evoked by ventrolateral funiculus (VLF) stimulation were analyzed in neonate rat motoneurons (MN) of spinal cord slices.The incidences of VLF-EPSPs was 80% (n = 28 ), among which 2 is preceded by inhibitory postsynaptic potential and 6 followed by slow EPSPs. Considering the distribution skewness of VLF-EPSP latency histogram, it was suggested that short- and long-latency EPSPs correspond respectively to mono- and poly-synaptic transmission respectively. The possible neurotransmitters mediating VLF-EPSPs were excitatory amino acids and non-NMDA receptors were critically involved in these synaptic transmissions,for both VLF-EPSP and glutamate-induced response were similary and almost completely abolished by kynurenic acid and DNQX. Typical spatial summation of VLF-EPSPs and EPSPs evoked by ventral root stimulation were observed in the same recorded MNs.

Key words: Motoneurons;Excitatory postsynaptic potentials;Descending activation;Ventrolateral funiculus;Spinal cord;Rat

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引用本文：

汪萌芽, 沈锷. 离体运动神经元对腹外侧索刺激的突触反应特征[J]. 生理学报 1997; 49 (6): .

Wang Mengya, Shen E. Characteristics of synaptic responses of motoneurons to ventrolateral funiculus stimulation in vitro. Acta Physiol Sin 1997; 49 (6): (in Chinese with English abstract).