The Effect of Benzyltetrahydropalmatine (BTHP) on Action Potentials and the Two Components of Delayed Rectifying Potassium Currents in Guinea Pig Ventricular Myocytes

摘要

The effects of BTHP on Ca~2+ -independent action potential and the two compo- nents of delayed rectifier potassium currents were studied din guinea pig single ventricular myocytes 143±16 ms to 184±21 ms (P＜0.01, n=5) without affecting either the RP or APA, and the APD pro- longing effects of BTHP were independent of extracellular Ca~2+. BTHP inhibited both I_kr(IC_50=7.9 μmol·L~-1) and I_ks(IC=22.4 μmol·L~-1) in a concentration-dependent fashion. The results demon- strated that BTHP had no obvious selectivity for I_kr and I_ks.