ABSTRACT
AIM To study the effects of propafenone on Kv 4 2 and Kv4 3 potassium current. METHODS Whole cell patch clamp technique was used to record changes of Kv4 2 and Kv4 3 potassium currents. RESULTS ① Propafenone redu ced the amplitude of Kv4 2 and Kv4 3 currents, in a concentration-dependent, IC 50 was 10 3 and 71 ?mol?L -1 respectively. ② Propafenone inhibi ted Kv4 2 and Kv4 3 current inactivation, 10 ?mol?L -1 propafenone acce lerates Kv4 2 current inactivation constant from (38 9?2 1) ms to (9 9?1 8) ms; and shifted the steady state inactivation curves of Kv4 2 current to negative potentials. 100 ?mol?L -1 Propaf enone accelerates Kv4 3 current inactivation constant from (144 8?20 8) ms t o (18 5?2 8) ms; and shifted the steady state inactivation curves of Kv4 2 c urrent to negative potentials. ③ propafenone inhibited Kv4 2 and Kv4 3 curren t activation, 10 ?mol?L -1 propafenone shifted the steady state activati on curves of Kv4 2 current to negative potentials. 100 ?mol?L -1 propafe none shifted the steady state activation curves of Kv4 2 current to negative po tentials. CONCLUSION Propafenone, maybe, also exerts its effects via blocking Kv4 2 and Kv4 3 current to antiarrhythmia.