Activation of Drosophila Sodium Channels Promotes Modification by Deltamethrin: Reductions in Affinity Caused by Knock-down Resistance Mutations

摘要: kdr and super-kdr are mutations in houseflies other insects that confer 30- 500-fold resistance to the pyrethroid deltamethrin. They correspond single (L1014F) double (L1014F+M918T) segment IIS6 linker II(S4–S5) of Na channels. We expressed Drosophila para channels with without these characterized their modification by All wild-type can be modified <10 nM deltamethrin, but high affinity binding requires channel opening: (a) is promoted more trains brief depolarizations than a long depolarization, (b) voltage dependence parallels opening, (c) toxin II from Anemonia sulcata , which slows inactivation. The reduce opening enhancing closed-state In addition, for open 20- 100-fold, respectively. Deltamethrin inhibits closing time remain once drug has bound. effectively number deltamethrin sites per two one. Thus, both potency efficacy insecticide action.