In vivo exposure of house flies to lethal concentrations of pyrethrum and cypermethrin greatly reduced binding of [3H]saxitoxin (STX) in nerve membrane preparations. The reduction in STX binding produced by cypermethrin was not concentration dependent, i.e., it did not increase as the concentration of cypermethrin was raised. Exposure of flies to lethal concentrations of diazinon or dieldrin also reduced STX binding, but to a lesser extent than with pyrethroids. Pyrethroids and other neuroexcitatory insecticides appear to cause an increased sodium ion influx, resulting in down-regulation of sodium channels. These results suggest that down-regulation of sodium channels is a consequence of intoxication by neuroexcitatory insecticides and that the reduction in STX binding is a consequence of a decrease in sodium channel density.
All Science Journal Classification (ASJC) codes
- Agronomy and Crop Science
- Health, Toxicology and Mutagenesis