Abstract:

The effects of cyhalothrin on the delayed rectifier potassium current in the central neurons of Helicoverpa armigera were studied using the patch clamp technique for the first time. The results showed that before application of cyhalothrin, 81% and 39% cells were activated at -30 mV and -40 mV (n=21), respectively. In 15 min after cyhalothrin (10^-5 mmol/L) application, 63% and 38% cells were activated at -40 mV and -50 mV (n=8), respectively. The amplitude of the current decreased significantly after application of cyhalothrin and the inhibition percentage reached 37.7% in 1 min (n=19). After the application, activation curve shifted to the negative direction and the value of V_h changed significantly, but the k value did not change remarkably. In conclusion, the results suggest that under the action of cyhalothrin, the potassium channels can be activated more easily and current amplitude can be inhibited significantly, this is related to the nervous insensitivity，and potassium channels of Helicoverpa armigera central neurons are the action targets of pyrethroid insecticides.

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Key words: Helicoverpa armigera, potassium channel, cyhalothrin, patch clamp, neurons, nerve sensitivity