雌酮对蟾蜍神经-肌接头传递的影响

Effects of Estrone on Transmission at Neuromuscular Junction of the Toad *

在蟾蜍离体坐骨神经－缝匠肌制备的肌细胞终板进行细胞内记录，研究了雌酮对神经－肌接头传递的影响。结果表明：雌酮（１０－４ｍｏｌ／Ｌ）加于浸浴液能增加１０μｇ筒箭毒处理组和１０ｍｍｏｌ／ＬＭｇＣｌ２处理组制备的终板电位振幅，但前者的增加更显著；雌酮加入浸浴液３０分钟后引起小终板电位的振幅和频率明显增加，但波形不改变，静息膜电位也不改变。这些结果提示，雌酮能增加神经－肌接头传递，且主要通过突触前机理的作用。

The effects of estrone on neuromuscular transmission were studied intracellularly at the muscle fiber endplate in isolated sciatic nerve sartorius muscle preparations of the toad(Bufo bufo gargarizans) in vitro. The results showed that estrone (10 -4 mol/L), added to bath medium, caused an increase in amplitudes of endplate potentials (EPP) both in 10μg tubocurarine treated and 10mmol/L MgCl 2 treated preparations, but the increase was more prominent in the former, and that estrone, 30 min after being added to bath medium, caused clear increase both in frequency and amplitude of miniature endplate potentials (MEPP), but the wave form of MEPP remained unchanged and the resting membrane potentials were also unchanged. These results suggest that estrone can increase neuromuscular transmission, which seems to involve primarily the presynaptic mechanism.