关附甲素对实验性心律失常和心肌收缩性的影响

关附甲素(GFA)浓度为20～3oμg·ml^-1时,可以降低无K⁺高Ca²⁺液灌流离体大鼠心脏诱发VT和VF的发生率。清醒大鼠ivGFA2.5～10mg·kg^-1,可依剂量性显著增加北草乌头碱引起室性早搏的用量。清醒犬ivGFA10mg·kg^-1,可逆转哇巴因引起VT,并对麻醉犬(10～20mg·kg^-1),由ACh诱发房颤有明显的抑制作用。GFA10mg·kg^-1iv可明显减慢麻醉犬或清醒犬心率,对心肌收缩性(V_max和V_pm)只有轻度而短暂的抑制,但对左室收缩压,心搏量和心输出量无明显影响。

EFFECTS OF GUAN-FU BASE A ON EXPERIMENTAL CARDIAC ARRHYTHMIAS AND MYOCAKDIAL CONTRACTILITY

Guan-fu base A(GFA)is a terpenoid alkaloid isolated from the tuber of Aconitumcoreanum in our institute. GFA(20～30mg·L^-1) reduced the ventricular tachycardia(VT)andventricular fibrillation(VF) rate induced by K⁺-free and high Ca²⁺ solution in Langendorf heart ofrats. Pretreatment of conscious rats with GFA 2.5～10 mg· kg^-1 iv, increased the amount ofbeiwutine necessary to preduce arrhythmias. Ouabain-induced VT in conscious dogs was reverted tosinus rhythm in 1～2min by iv GFA 9～10 mg· kg^-1. GFA 10～20 mg·kg^-1 iv was also foundto be effective in protecting anesthetized dogs from atrial fibrillation induced by topical application of ACh. GFA 10 mg·kg^-1 iv obviously decreased heart rate and prolonged the P-R interval,but slightlyaffected the myocardial contractility in anesthetized dog GFA showed no obvious effect on strokevolume and cardiac output in conscious dogs.In conclusion, GFA showed therapeutic and prophylactic effect on different models ofexperimental arrhythmias without causing marked effect on myocardial contractility.