Deltamethrin: A neurophysiological study of the sites of action

Recent experiments on the mode of action of pyrethroids have indicated that those pyrethroids containing an α-cyano phenoxybenzyl group may act on GABA-mediated chloride channels. The crayfish stretch receptor neuron provides a useful preparation for examining the effects of pyrethroids on these channels and on sodium channels. The lowest concentration of deltamethrin to have an effect on sodium channels was 10⁻¹² M, but the response of the preparation to GABA appeared to be unaffected by concentrations of deltamethrin up to 10⁻⁷ M. Although 10⁻⁶ M deltamethrin had a slight effect on the GABA response of the dactyl abductor muscle, it appears that the majority of the effects of cyano pyrethroids in invertebrates could be accounted for solely by their action on sodium channels.