双复磷和酰胺磷定对梭曼中毒神经肌肉接头终板区持续性去极化的对抗作用

Antagonism of obidoxime and HI-6 against sustained depolarization in endplate area of neuromuscular junction intoxicated with soman

在大鼠的膈肌离体不均匀牵张肌肉标本（ＩＮＳＭＰ）上，肟类化合物双复磷（Ｏｂｉ）和酰胺磷定（ＨＩ－６）对正常神经肌肉接头（ＮＭＪ）具有轻度抑酶作用，在突触后抑制作用的浓度（１．０ｍｍｏｌ／ＬＯｂｉ和０．５，１．０ｍｍ０ｌ／ＬＨＩ－６）下可对抗梭曼致终板区持续性去极化（ＳＤ）的产生。冲洗药物后。Ｏｂｉ的对抗作用完全消失，ＨＩ－６的对抗作用不完全消失。表明Ｏｂｉ和ＨＩ－６主要以突触后抑制作用生理性地对抗梭曼中毒致ＳＤ的产生，其中ＨＩ－６有部分酶重活化作用。也进一步表明ＳＤ是梭曼中毒ＮＭＪ上主要电生理反应。

On selected endplates in isolated nonuhiform stretched muscle preparation(INSMP) of rat diaphragm,the antagonisms of obidoxime(Obi) and HI-6 against soman intoxication were investigated.The sustaineddepolarization(SD)in endplate area was induced when the phrenic nerve was repetitively stimulated 10 minutes af-ter 5.5μmol / L soman. During the prolonged plateau of SD,no EPPs could be evoked. Obi(0.01～1.0 mmol / L)and HI-6(0.01-1.0 mmol / L)could antagonize the occurrence of SD concentration dependently either by in-creasing the number of EPPs before SD and shortening the duration of SD by 70 % or by aborting SD with thereappearance of EPPs.SD restored completely after washing out Obi.SD restored incompletely after washing outHI-6. In the same drug concentration range,Obi and HI-6 have weak postsynaptic inhibiting and partialacetylcholinesterase inhibiting effects.It is suggested that Obi and HI-6 can antagonize the occurrence of SD bytheir postsynaptic inhibiting effect.HI-6 may have the ability of reactiating ACH E intoxicated by soman.