摘要
经阳离子交换和反相HPLC柱层析从海南捕鸟蛛 (Seleconosmiahainana)粗毒中分离到 1种新的神经毒素 ,命名为海南捕鸟蛛毒素 -Ⅴ (Hainantoxin Ⅴ ,HNTX Ⅴ ) ,MALDI TOF质谱鉴定分子量为 396 9 5Da。在全细胞记录膜片钳模式下 ,HNTX Ⅴ对成年大鼠背根神经节 (DRG)细胞河豚毒敏感型 (TTX S)钠电流有抑制作用 ,但对河豚毒不敏感型 (TTX R)钠电流无明显影响。HNTX Ⅴ对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 4 6 8nmol/L。HNTX Ⅴ不影响TTX S钠电流的激活相和失活相 ,对钠通道的激活阈值和最大激活电压也无明显改变 ,表明HNTX Ⅴ影响钠通道的作用机制明显有别于δ ACTXs等蜘蛛毒素。推测HNTX Ⅴ很可能类似于河豚毒、Saxitoxin和 μ conotoxins ,同样作用于钠通道的位点S1。
By means of ion exchange chromatograph and reverse phase HPLC, a new neurotoxin, named as Hainantoxin Ⅴ (HNTX Ⅴ), was isolated from the venom of the spider Seleconosmia hainana . The molecular weight of HNTX Ⅴ was 3?969 5 Da measured by MALDI TOF mass analysis. Under whole cell patch clamp mode, HNTX Ⅴ could inhibit the tetrodotoxin sensitive (TTX S) sodium currents while it had no significant effect on tetrodotoxin resistant (TTX R) ones on the dorsal root ganglion (DRG) neuron of adult rats. The inhibition of TTX S sodium currents by HNTX Ⅴ was concentrate dependent with the IC 50 value of 46 8 nmol/L. The toxin did not effect the active and inactive time course of currents and did not have the effect on the active threshold of sodium channels and the voltage of peak inward current either, indicating that HNTX Ⅴ inhibited mammalian voltage gated sodium channels through a novel mechanism distinct from other spider toxins such as δ ACTXs. We suggested that HNTX Ⅴ maybe target the site 1 of sodium channels in a similar manner to TTX, Saxitoxin and μ conotoxins.
基金
国家自然科学基金资助项目 (3 93 70 15 2 )~~
