논문 상세보기
Modification of Insect Sodium Currents by a Pyrethroid Permethrin and Positive Cooperativity with Scorpion Toxins KCI 등재
피레스로이드계 살충제 퍼메트린이 Heliothis virescens 중추신경세포에 있는 나트륨채널에 작용하는 기작을 전기생리학적으로 연구
pp.117-128
본 연구는 피레스로이드계 살충제인 퍼메트린이 Heliothis virescens의 중추신경세포의 나트륨채널에 어떻게 작용하는 가를 전기생리학적으 로 관찰하였다. 퍼메트린은 나트륨채널의 꼬리전류(INa-tail)를 지속적으로 증가시켰으며 이러한 비정상적인 나트륨 전류증가가 나방류의 신경계에 과도한 흥분을 일으겨 살충작용을 하는 것으로 생각된다. 이러한 살충작용은 전갈독과 함께 사용했을때 약 8배의 증가가 있었음을 확인하였다. 전 갈독이 살충제의 독성을 강화하는 분자생리학적 기전연구가 계속되면 해충방제에 많은 기여를 할 것으로 생각된다.
In this study, we have examined pyrethroid actions on sodium channels in the pest insect Heliothis virescens. The synthetic pyrethroid permethrin increased steady-state sodium current in H. virescens central neurons and prolonged tail currents (INa-tail) due to extreme slowing of sodium channel deactivation. Prolongation of INa-tail was evident at permethrin concentrations as low as 60 nM, which modified ~1.7% of sodium channels and 10 μM permethrin modified about 30% of channels. The average time constant (τ1) of tail current decay was ~335 ms for permethrin-modified channels. These modified channels activated at more negative potentials and showed slower activation kinetics, and failed to inactivate. Permethrin modification of sodium channels was dramatically potentiated by the α scorpion toxin LqhαIT, showing positive cooperativity between two binding sites. The amplitude of the tail current induced by 0.3 μM permethrin was enhanced ~8-fold by LqhαIT (200 pM). Positive cooperativity was also observed between permethrin and the insect-specific scorpion toxin AaIT as 10 nM permethrin potentiated the shift of voltage dependence caused by AaIT (~2-fold).
초 록
Materials and Methods
Neurotoxins
Preparation of H. virescens central neurons
Whole-cell recordings of neuronal sodium currents
Results
Permethrin shifts voltage-dependent activation tomore negative potentials but slows sodium channelopening
The insect selective alpha-scorpion toxin LqhαITpotentiates permethrin action
Permethrin enhances the action of the scorpiontoxin AaIT
Discussion
Modification of H. virescens sodium channels bypermethrin
High selectivity of pyrethroids on insect sodiumchannels
Cooperative actions of pyrethroids and scorpiontoxins
Literature Cited
