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.