1. The actions of a chromatographically identified extract of the marine dinoflagellate Ostreopsis lenticularis, named ostreotoxin-3 (OTX-3), were studied on frog isolated neuromuscular preparations. 2. OTX-3 (1-10 microg ml(-1)) applied to cutaneous pectoris nerve-muscle preparations depolarized skeletal muscle fibres and caused spontaneous contractions. The depolarization was neither reversed by prolonged washing nor by (+)-tubocurarine. 3. OTX-3 decreased the amplitude of miniature end plate potentials (m.e.p.ps) but did not affect their frequency. 4. Extracellular recording of compound action potentials revealed that OTX-3 affected neither excitability nor conduction along intramuscular nerve branches. 5. End-plate potentials (e.p.ps) elicited by nerve stimulation were reduced in amplitude by OTX-3 and even showed reversed polarity in junctions deeply depolarized by the toxin. 6. Membrane depolarization induced by OTX-3 was decreased about 70% in muscles pretreated for 30 min with 10 microM tetrodotoxin. In contrast, muscles pretreated with 5 microM mu-conotoxin GIIIA were completely insensitive to OTX-3-induced depolarization. 7. OTX-3 did not affect e.p.p. amplitude and the quantal content of e.p.ps in junctions in which muscle depolarization was abolished by mu-conotoxin GIIIA. 8. OTX-3 is a novel type of sodium-channel activating toxin that discriminates between nerve and skeletal muscle membranes.

译文

1.在蛙类分离的神经肌肉制剂上研究了一种色谱鉴定的海洋鞭毛鞭毛骨癣菌提取物,称为ostreotoxin-3(OTX-3)的作用。 2.将OTX-3(1-10 microg ml(-1))应用于皮肤胸大肌神经肌肉制剂可使骨骼肌纤维去极化并引起自发性收缩。长时间洗涤或()-微管尿素均不能逆转去极化作用。 3. OTX-3减小了微型端板电位的幅度(m.e.p.ps),但不影响其频率。 4.复合动作电位的细胞外记录显示,OTX-3既不影响兴奋性也不影响沿肌内神经分支的传导。 5.神经刺激引起的终板电位(e.p.ps)被OTX-3降低,甚至在毒素深层去极化的连接处显示相反的极性。 6.在用10 microM河豚毒素预处理30分钟的肌肉中,由OTX-3诱导的膜去极化减少了约70%。相反,用5 microM mu-conotoxin GIIIA预处理的肌肉对OTX-3诱导的去极化完全不敏感。 7. OTX-3不会影响e.p.p. mu-conotoxin GIIIA消除了肌肉去极化的连接处的振幅和e.p.ps的含量。 8. OTX-3是一种新型的钠通道激活毒素,可区分神经膜和骨骼肌膜。

+1
+2
100研值 100研值 ¥99课程
检索文献一次
下载文献一次

去下载>

成功解锁2个技能,为你点赞

《SCI写作十大必备语法》
解决你的SCI语法难题!

技能熟练度+1

视频课《玩转文献检索》
让你成为检索达人!

恭喜完成新手挑战

手机微信扫一扫,添加好友领取

免费领《Endnote文献管理工具+教程》

微信扫码, 免费领取

手机登录

获取验证码
登录