Synthesis and characterization of huwentoxin-Ⅳ,a neurotoxin inhibiting central neuronal sodium channels
会议名称：《第八届中国生物毒素学术研讨会》
会议日期：2007年
学科分类：0710[理学-生物学] 07[理学] 071006[理学-神经生物学]
关 键 词：spider toxin sodium channel whole-cell recording hippocampus
摘 要：Our previous work demonstrated that huwentoxin-Ⅳ was an inhibitor cystine knot peptide from Chinese tarantula Ornithoctonus huwena venom that blocked tetrodotoxin-sensitive voltage-gated sodium channels from mammalian sensory ***,the actions of the neurotoxin on central neuronal sodium channels remain *** this study,we chemically synthesized native huwentoxin-Ⅳ and found that sodium channel isoforms from rat hippocampus neurons were also sensitive to native and synthetic toxins,but the toxin binding affinity (IC50 .4 μM) was 12-fold lower than to peripheral *** blockade by huwentoxin-Ⅳ could be reversed by strong depolarization due to the dissociation of toxin-channel complex as observed for receptor site 3 ***,small unilamellar vesicles binding assays showed that in contrast to ProTx-Ⅱ from the tarantula Thrixopelma pruriens,huwentoxin-Ⅳ lacked the ability to partition into the negatively charged and neutral phospholipid bilayer of artificial *** findings indicated that huwentoxin-Ⅳ was a sodium channel antagonist preferentially targeting peripheral isoforms via a mechanism quite different from ProTx-Ⅱ.