关键词: 虎纹捕鸟蛛, 虎纹毒素-III, 美洲蜚蠊, 背侧不成对中间神经细胞, 钠离子通道 全细胞膜片钳技术

Abstract: Huwentoxin-III purified from the venom of the Chinese bird spider, Ornithoctonus huwena (Wang et al.), is an insect neurotoxic peptide. The effects of huwentoxin-III on neuronal voltage-gated ion channels were studied by using whole-cell patch clamp technique. Huwentoxin-III specifically inhibited voltage-gated sodium channels in dorsal unpaired median neurons of adult cockroach Periplaneta americana (IC50≈1.106 μmol/L) while having no evident effect on voltage-gated potassium channels. HWTX-III inhibited insect voltage-gated sodium channels through a novel mechanism distinctive from other spider toxins, did not affect the activation and inactivation kinetics, and not evidently shift the steady-state inactivation curve. Thus, its specificity and novel mechanism on insect neuronal voltage-gated sodium channels make it an interesting tool for investigating the multiple molecular forms of voltage-gated sodium channels and exploiting new and safe insecticides.

Key words: Ornithoctonus huwena, huwentoxin-III, Periplaneta americana, dorsal unpaired median neurons, sodium channel, whole-cell patch clamp technique