胆碱酯酶抑制剂对胆碱能突触传递的差异性作用

DISTINCTIVE ACTIONS OF CHOLINESTERASE INHIBITORS ON CHOLINERGIC SYNAPTIC TRANSMISSION

应用细胞内记录技术，观察了毒扁豆碱（Ｐｈｙｓ）和石杉碱甲（Ｈｕｐ－Ａ）对离休蟾蜍椎旁神经节胆碱能传递的影响。发现Ｐｈｙｓ或Ｈｕｐ－Ａ１μｍｏｌ／Ｌ升高节前神经刺激诱发的顺行动作电位（ＡＰ）发放率。Ｐｈｙｓ５０～１００μｍｏｌ／Ｌ同时抑制顺行ＡＰ及外源性ＡＣＨ电位（ｎ＝６），但Ｈｕｐ－Ａ ５０～３００μｍｏｌ／Ｌ不仅更加强烈、快速、持久地增大突触性及ＡＣｈ电位（ｎ＝２１），并在６２％的细胞使单次节前刺激诱发长时程去极化反应，结果表明，不同胆碱酯酶抑制剂对胆碱能传递有不同的药理和毒理学作用。

The effcets of physostigmine(phys)and huperzine A(Hup-A)on the cholinergic transmission of isolated toad paravertebral ganglia were studied by intracellular reeording tcehniques.It was found that the evoked rate of orthodromie aetion potential by preganglionie stimulation was increased by either phys or Hup-A 1 μmol/L superfusion. At high concentration of 500-100μmol/L,phys depressed both the synaptie and exogenous ACh-induced responses(n=6).However, Hup-A50-300 μmol/L exhibited not only a faster,stronger and longer enhancement of both synaptic responses and ACh-induced potential(n=21),but also an facilitation of the gencration of long-lasting depolarization clieited by single prcganglionic stimulation in 62% cells. The results suggested that the distinctive pharmacologieal and toxicological actions on the cholinergic synaptic transmission or sympathetic ganglia were presented by different cholinesterase inhibitors.