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新生大鼠脊髓薄片中的运动神经元对腹外侧索刺激的反应

汪萌芽

皖南医学院细胞电生理研究室. 安徽,芜湖(241001)

摘要

大鼠腹外侧索刺激可在80％的运动神经元(MN)诱发去极化反应(EPSP)。在静息电位水平EPSP的潜伏期、达峰时间、幅度、半衰时间和时程分别为1. 2±0.2ms、2.6±0.4ms、13±3mV、5.3±1.6ms和31±8ms。EPSP呈等级性和膜电位依赖性, 平均翻转电位为-8mV, 潜伏期在0.1 —5Hz频率的刺激时相对恒定, 刺激频率>20Hz时EPSP变小或被取消。EPSP在低钙高镁溶液中被阻抑但在无镁溶液中增强。犬尿烯酸(0.5—1mmol/L)可逆地阻断EPSP, 但氯胺酮(50—100μmol/L)仅部分抑制之。结果表明腹外侧索中的下行纤维可能释放兴奋性氨基酸而激活MN。

关键词： 脊髓; 运动神经元; 下行激活; 突触反应; 细胞内记录

Responses of motoneurons to ventrolateral funiculus stimulation in neonate rat spinal cord slices

Wang Mengya

Cell Electrophysiology Laboratory, Wannan Medical College. Wuhu,Anhui

Abstract

In more than 80% MNs, depolarization potentials with latency of 1.2±0.2 ms could be evoked by focal stimulaton of ventrolateral funiculus. when recorded at resting potential of -70±6mv, the time -to -peak, amplitde, half-decay time and duration of EPSPs to suprathreshold stimuli were respectively,2.6±0.4 ms, 13±8 ms.The EPSPs was observed in spite of varying stimulus frequency from 0.1 to5 Hz.Up on increasing stimuation requency>20Hz, EPSPs began to decrease and finally disappeared.In 3 MNs tested, the mean reversal potential of ESPs was -8mV.Loca/high Mg solution consistently attenuated but Mg-free solution enhanced the EPSPs.EPSPs were reversibly depressed by kynurenic acid and partially inhibited by ketamine.

Key words: Spianl cord;Motoneurons;Descending activation;Synaptic response;Glutamate

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引用本文：

汪萌芽. 新生大鼠脊髓薄片中的运动神经元对腹外侧索刺激的反应[J]. 生理学报 1994; 46 (2): .

Wang Mengya. Responses of motoneurons to ventrolateral funiculus stimulation in neonate rat spinal cord slices. Acta Physiol Sin 1994; 46 (2): (in Chinese with English abstract).