Results: 1) E2 or P prolonded AP duration (APD20, APD50, APD90 and APD), RPT and DPT, slowed down the maximal rate of rise of phase 0(Vmax), decreased the action potential amplitude(APA).

• 结果:1)E_2与P单独作用均可使家兔窦房结细胞动作电位时程(APD_(20)、APD_(50)、APD_(90)、APD)延长,动作电位幅度(APA)及0期最大除极速率(V_(max))明显降低,0期除极时间(DPT)延长。