乙醇对蟾蜍神经-肌接头传递的影响

目的　研究乙醇对神经肌肉接头 (NMJ)兴奋传递的影响及可能机制。方法　用微电极细胞内记录的方法 ,在 2 0只成年蟾蜍的坐骨神经 -缝匠肌标本上研究乙醇对终板电位 (EPP)和微小终板电位 (MEPP)的影响。结果　乙醇可引起 EPP振幅改变 ,影响 NMJ的兴奋传递 ,而且其影响具有明显的量效依赖关系 ,适当浓度的乙醇能明显地增加 EPP振幅 ,促进 NMJ的兴奋传递。乙醇还可使 MEPP的频率增加 ,但对 MEPP的振幅无影响。结论　初步确定乙醇促进 NMJ兴奋传递的部位是在突触前 ,其机制是使突触前释放的递质的量子数增加

The Effects of Ethanol on Neuromuscular Junctions of Adult Toad

Objective To investigate the effects of ethanol on the transmission at the neuromuscular junctions(NMJ) and the possible mechanism thereby.Methods The effects of ethanol on the endplate potential(EPP) and miniature endplate potential(MEPP) of sciatic nerve sartorius muscle preparations of 20 adult toads(Bufo bufo gargarizans) were studied in vitro by means of intracellular microelectrode recording.Results Ethanol could cause the changes in EPP amplitude so as to influence the transmission at NMJ,and the effects apparently depended on the concentration of the ethanol. A proper concentration of ethanol could produce a significant increase in EPP amplitude and therefore facilitate the transmission at the NMJ.A proper concentration of ethanol also could produce a significant increase in MEPP frequency but had no influence on MEPP amplitude.Conclusion Ethanol can increase the quantal number of transmitters released from presynaptic part.That may be one of the reasons why ethanol can facilitate the transmission at the NMJ.