2－氯－4－溴－α－甲基肉桂酸钠盐对蟾蜍神经肌接头兴奋传递的影响

The Effects of 2-Chloro-4-Bromo-α-Methylcinnamic Acid on the Neuromuscular Transmission of Toad

在蟾蜍坐骨神经－缝匠肌标本上进行细胞内记录，观察２－氯－４－溴－α－甲基肉桂酸钠盐三个浓度组对神经肌接头电活动的影响。０．１ｍｍｏｌ／Ｌ对肌细胞静息膜电位和终板电位无影响；１ｍｍｏｌ／Ｌ对肌细胞静息电位也没有影响，但使终板电位从１．８８±０．２９ｍＶ减小到０．２６±０．０６ｍＶ（ｎ＝８，ｐ＜０．０１），双脉冲易化作用减弱，甚至抑制；１Ｏｍｍｏｌ／Ｌ使终板电位完全消失，使肌细胞静息膜电位从８２．１３±１．０５ｍＶ降至４８．６３±１．７６ｍＶ（ｎ＝８）。结果表明２－氯－４－溴－α－甲基肉桂酸钠盐对蟾蜍神经肌肉接头传递有阻遏作用，其阻遏作用可能主要是通过突触前机理。

The effects of 2-chloro-4-bromo-α-methylinnamic and sobium(SC1001Na)on neuro-muscular transmission were tested by means of intra-cellular recordings in isolated sciatic nerve-sartoriuspreparations of toad. The results were:(1) at a con-centration of 0.1mmol/L、SC 1001 Na had no effect onend-plate potential(EPP );at a concentration of 1mmol/L, SC1001 Na reduced the amplitude of theEPP significantly,and the paired-pulse facilitation wasalso decreased :at a concentration of 10mmol /L,SC1001 Na blocked the EPP completely;(2)the 0.1mmol/L and 1mmol/L groups of drug had no effect onthe resting potential of the toad muscle fibers ; theresting potential was reduced significantly bySC1001Na at the concentration of 10mmol/L,the ac-tion of 10mmol/L drug was irreversible. These resultssuggest that SC1001 Na may block the neuromusculartransmission of toad.and the blocking effect might bemainly due to a presynaptic mechanism.