新斯的明引起大鼠神经肌接头突触后膜持续性去极化特点  

Characteristics of sustained depolarization of neuromuscular junction induced by neostigmine in rat

作　　者：李立君[1] 刘传缋[1] 

机构地区：[1]军事医学科学院毒物药物研究所,北京100850

出　　处：《中国药理学与毒理学杂志》2000年第4期273-277,共5页Chinese Journal of Pharmacology and Toxicology

摘　　要：采用大鼠膈肌不均匀牵张肌肉标本 ,观察可逆性胆碱酯酶抑制剂新斯的明引起神经肌接头突触后膜持续性去极化特点 .结果发现 ,新斯的明 ( 2 .5-5μmol· L-1)浴槽内给药引起的持续性去极化( SD)时程比压力给药 ( 1 mmol· L-1,32 k Pa,2 - 5s)时长 ,结果提示压力给药引起的 SD时程仅相当于浴槽内低浓度药物所引起者 .在本实验条件的多数情况下 ,压力给药引起 SD的平台期 ,复极期以及复极后的一段时间内出现频率显著增高的小终板电位 ( m EPP) ,并且这种高频率的 m EPP只伴随 SD的产生而出现 .而在浴槽内给予高浓度新斯的明引起的 SD过程中 ,m EPP显著减少 .结果提示 ,可逆性胆碱酯酶抑制剂新斯的明在低浓度时引起的 SD过程中 ,不仅突触后膜的烟碱受体并没有完全失敏 ,而且突触前膜自发释放 ACh显著增加 .The characteristics of sustained depolarization (SD) of neuromuscular junction induced by neostigmine in isolated non uniform stretched muscle preparation of rat diaphragm was studied. The results showed that the duration of SD induced by neostigmine(2.5-5 μmol·L -1 ) applied to the bath directly was longer than that applied to the bath through a pressure ejector(1 mmol·L -1 ,32 kPa, 2-5 s). In most cases of neostigmine applied through a pressure ejector, high frequency of miniature end plate potentials (mEPPs) appeared on the plateau of SD, at the repolarization phase of SD and a certain period after SD. Furthermore, the high frequency of mEPPs was appeared only after SD was produced. It is suggested that nicotinic acetylcholine receptors on post junctional membrane be not complete desensitization during SD, and acetylcholine releasing spontaneously from nerve terminal increase markedly in the presence of neostigmine applied through a pressure ejector.

关 键 词：新斯的明 持续性去极化 神经肌接头 电位测定法 

分 类 号：R96[医药卫生—药理学]