海南捕鸟蛛毒素-IV对大鼠背根神经节细胞钠通道的抑制影响(英文)  

Inhibition of Sodium Channels in Rat Dorsal Root Ganglion Neurons by Hainantoxin-IV, a Novel Spider Toxin

作　　者：肖玉成[1] 梁宋平[1] 

机构地区：[1]湖南师范大学生命科学学院,长沙410081

出　　处：《生物化学与生物物理学报》2003年第1期82-85,共4页

基　　金：国家自然科学基金重大项目资助 (No .30 170 193 )~~

摘　　要：海南捕鸟蛛毒素 IV(HNTX IV)是从中国捕鸟蛛Seleconosmiahainana粗毒中分离得到的一种肽类神经毒素 ,在成年大鼠背根神经节 (DRG)细胞上观察了该毒素对电压门控钠通道的影响。在全细胞膜片钳条件下 ,HNTX IV能明显抑制哺乳动物神经性河豚毒敏感型 (TTX S)钠电流 ,但不影响河豚毒不敏感型 (TTX R)钠电流。HNTX IV对DRG细胞TTX S钠电流的抑制作用具有浓度依从性 ,其有效半抑制浓度 (IC50 )为 44 .6nmol/L。该毒素不影响DRG钠电流的激活与失活时间特征 ,但能导致钠通道的半数稳态失活电压向超极化方向漂移约 10 .1mV。结果表明HNTX IV是一种新型的蜘蛛毒素 ,其影响电压门控钠通道的机制可能有别于那些结合于通道位点 3来延缓钠电流失活时间特征的蜘蛛毒素如δ 澳洲漏斗网蛛毒素、μ 美洲漏斗网蛛毒素I VI等。The effects of Hainantoxin-IV (HNTX-IV), a neurotoxic peptide isolated from the venom of the Chinese bird spider Seleconosmia hainana, on the adult rat dorsal root ganglion (DRG) neurons were investigated. Using the whole-cell patch-clamp technique HNTX-IV inhibited mammal neural TTX-sensitive (TTX-S) sodium currents evidently but the toxin failed to affect TTX-resistant (TTX-R) ones. The inhibition of HNTX-IV is dose-dependent with the IC 50 value of 44.6 nmol/L. The toxin didn’t affect the activation and inactivation kinetics of sodium currents, but it caused a 10.1 mV hyperpolarizing shift in the voltage midpoint of steady-state sodium channel inactivation on DRG neurons. The results indicated that HNTX-IV, a novel spider toxin, maybe alternate voltage-gated sodium channels through a mechanism distinct from other spider toxins such as δ-ACTXs, μ-agatoxins I-VI which targeted the receptor site 3 to slow the inactivation kinetics of sodium currents.

关 键 词：蜘蛛毒素 钠电流 全细胞膜片钳 海南捕鸟蛛毒素-Ⅳ 大鼠 背根神经节细胞 钠通道 抑制 

分 类 号：Q591[生物学—生物化学]