当归A_3部位对心肌生理特性和动作电位的影响

目的　研究A3 部位对离体心肌生理特性和心室乳头肌动作电位的影响。方法　采用常规离体器官实验法记录右房自搏频率、心肌收缩力和功能性不应期 ;采用标准细胞内微电极技术记录动作电位 (AP)。结果　A3 部位 (10～ 16 0mg·L-1)能显著抑制右心房的自搏频率 ,16 0mg·L-1时可使右心房停搏 ;它剂量依赖性地降低左心房的收缩力 ,IC50 为5 2 3mg·L-1;它还明显延长功能性不应期 (FRP) ,10 0mg·L-1时 ,使FRP从给药前的 10 6ms延长至 130ms ;A3 部位剂量依赖性地降低动作电位振幅 (APA) ,缩短复极 2 0 %时程 (APD2 0 )和复极 90 %时程 (APD90 ) ,对静息电位 (RP)无影响。结论　当归A3 部位对心肌生理特性和动作电位的作用可能与其阻Ca2 + 、Na+ 内流和促K+ 外流有关

Effects of A3 site from Angelica naphtha on myocardial physiological properties and action potentials

AIM To study the effects of A 3 site (components), extracted from Angelica naphtha (total oil),on physiological properties of isolated rat atrium and action potential of isolated guinea pig ventricular papillary muscles. METHODS Spontaneous beats, contractile force and functional refractory period(FRP) of isolated atrial muscle were recorded according to the regular methods. Standard microelectrode intracellular recording technique was used to record action potential(AP) of ventricular papillary muscles. RESULTS A 3 site(10～160 mg·L -1 ) dramatically inhibited spontaneous beats of isolated rat right atrium and made beats stop with 160 mg·L -1 . A 3 site concentration dependently reduced contractile force of isolated rat left atrium induced by electrostimulating, with the IC 50 value of 52 3 mg·L -1 . A 3 site(40～100 mg·L -1 ) obviously prolonged FRP. The FRP was prolonged from 106 ms (as control) to 130 ms at final concentration of 100 mg·L -1 . A 3 site decreased action potential amplitude (APA), shortened 20%APD(APD 20 ) and 90%APD(APD 90 ), but had no significant effect on RP of AP. CONCLUSION The mechanism of these effects of A 3 site on myocardial physiological properties and action potential was probably associated with blocking the influx of Ca 2+ and Na +, promoting K + outflux.