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Effects of #beta#--cypermethrin on voltage-gated potassium channels in rat hippocampal CA3 neurons

Fu Zhiyan, Du Chunyun, Yao Yang, Liu Chaowei, Tian Yutao, He Bingjun, Zhang Tao, Yang Zhuo

College of Medicine,Nankai University.Tianjin 300071；China

Abstract

The effects of #beta#-cypermethrin （consisting of #alplha#-cypermethrin and #theta#-cypermethrin） on the transient outward potassium current （I_(A)） and delayed rectifier potassium current （I_(K)） in freshly dissociated hippocampal CA3 neurons of rats were studied using whole-cell patch-clamp technique. The results indicated that #alpha#-cypermethrin increased the value of I_(A) and #theta#-cypermethrin decreased the value of I_(A), though both of them shifted steady activation curve of I_(A) towards negative potential. #theta#-cypermethrin contributed to the inactivation of I_(A). The results also showed that #alpha#-cypermethrin and #theta#-cypermethrin decreased the value of I_(K), and shifted the steady state activation curve of I_(K) towards negative potential. Both #alpha#-cypermethrin and #theta#-cypermethrin had no obvious effects on the inactivation of I_(K). #theta#-cypermethrin prolonged recovery process of I_(K). These results imply that both transient outward potassium channels and delayed rectified potassium channels are the targets of #beta#-cypermethrin, which may explain the mechanism of toxical effects of #beta#-cypermethrin on mammalian neurons.

Key words: voltage-activated K~(+) current;patch-clamp technique;Neurons;cypermethrin

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Citing This Article：

Fu Zhiyan, Du Chunyun, Yao Yang, Liu Chaowei, Tian Yutao, He Bingjun, Zhang Tao, Yang Zhuo. Effects of #beta#--cypermethrin on voltage-gated potassium channels in rat hippocampal CA3 neurons. Acta Physiol Sin 2007; 59 (1): 63-70 (in Chinese with English abstract).