Tx3-4 a toxin from the venom of spider Phoneutria nigriventer blocks calcium channels associated with exocytosis
- 作者：Cé ; lio José ; de Castro Junior ; Ana Cristina N. Pinheiro ; Cristina Guatimosim ; Marta N. Cordeiro ; Aless ; ra H. Souza ; Michael Richardson ; Marco A. Romano-Silva ; Marco Antô ; nio M. Prado ; Marc
- 关键词：Phoneutria toxin ; Calcium channels ; Exocytosis ; Synaptosomes ; ω ; -CgTX MVIIC ; ω ; -CgTX GVIA ; ω ; -Aga IVA
- 刊名：Neuroscience Letters
- 出版年：2008
- 期刊代码：52_03043940
- 类别：neu
- 出版时间：11 July 2008
- 卷：439
- 期：2
- 页码：170-172
- 文件大小：203 K
摘要
The purpose of the present work was to investigate the pharmacological action of a calcium channel-blocking toxin from the venom of the spider Phonetic nigriventer, Tx3-4 on calcium channels coupled to exocytosis of synaptic vesicles. Tx3-4 blocked KCl-induced exocytosis of synaptic vesicles with an IC50 of 1.1 nM. To investigate whether the target of Tx3-4 overlaps with known calcium channels that mediate calcium entry and exocytosis, we used ω-toxins that interact selectively with neuronal calcium channels. The results indicate that the main population of voltage-sensitive calcium channels altered by Tx3-4 is P/Q calcium channels. In conclusion, Tx3-4 is a potent inhibitor of calcium channels involved in the KCl-induced exocytosis of synaptic vesicles in brain cortical synaptosomes.