细胞外钾离子对KV4.3通道失活动力学的影响

Effects of External K^+ on KV4.3 Inactivation Kinetics

观察细胞外钾离子对KV4.3通道失活动力学的影响。用电压钳技术研究非洲爪蟾卵母细胞中表达的KV4.3通道在细胞外正常浓度(2mmol/L)钾离子([K+]O)和高浓度(98mmol/L)时的通道电流。结果:与2mmol/L[K+]O的作用相比较,98mmol/L[K+]O加速了KV4.3通道的开放状态失活,并有加快关闭状态失活的趋势,同时减慢失活后恢复,但对KV4.3稳态失活无明显作用。结论:在正常生理条件下,KV4.3通道失活主要由开放状态失活所主导。

To explore the effects of external K^＋ （ [ K^＋ ] o ） on KV4.3 inactivation kinetics, KV4.3 currents expressed in Xenopus oocytes were recorded and analyzed in 2 and 98 mmol/L [ K^＋ ] o with voltage-clamp technique. Results ： Comparing with the results derived in 2 mmol/L [ K^＋ ] o, open-state inactivation became faster, recovery from inactivation slowed and the closed state-inactivation tended to accelerate, but no change could be found with the steadystate inactivation in 98 mmol/L [ K^ ＋ ]0. Conclusions - KV4.3 iinactivates predominantly by the inactivation of the open state under the physiological conditions.