血管紧张素Ⅱ及牛磺酸对体外培养乳鼠肥大心肌细胞心律失常发生的作用

在培养72h的乳鼠心肌细胞,血管紧张素Ⅱ(angiotensinⅡ,AgnⅡ)1,10,100和1000nmol·L^-1时,可浓度依赖性地增加细胞搏动频率;而牛磺酸5,10和20mmol·L^-1不影响心肌细胞搏动频率,但能浓度依赖性地拮抗AngⅡ100nmol·L^-1加快心肌细胞搏动频率的作用。AngⅡ100nmol·L^-1连续作用7d引起的培养乳鼠肥大心肌细胞搏动频率加快,动作电位APA升高,APD₅₀和APD90延长,SCL缩短;哇巴因50nmol·L^-1诱发的心肌细胞搏动节律失常发生率高于常规培养组。牛磺酸20mmol·L^-1可抑制AngⅡ引起的上述改变,并降低哇巴因诱发的心律失常发生率。

EFFECT OF ANGIOTENSIN AND TAURINE ON ARRHYTHMIA IN CULTURED NEONATAL RAT HYPERTROPHIC HEART MYOCYTES

Angiotensin (Ang)Ⅱ(1,10,100 and 1000nmol·L^-1)was found to increasespontaneous contractile frequency dose-dependently in neonatal rat cardiac myocytes cultured for 3 d.After exposure to Ang Ⅱ(100 nmol·L^-1)for 7 d,neonatal rat heart cells became hypertrophy withincreased frequency ,elevated APA ,prolonged ADP₅₀ and ADP₉₀ ,and shortened SCL.Addition ofouabian(Oua) 50 nmol·L^-1 to the hypertrophic myocytes caused more frequent arrhythmia.Taurine(20 mmol·L^-1)was shown to inhibit these changes induced by Ang Ⅱ.These results suggest thatAng Ⅱ can increase autorhythmicity as well as sensibility to Oua in cultured catdiac myocytes.Theseeffects might be related to the promotion of Ca²⁺ influx.