The Effect of Tanshinone on L-type Calcium Current in Hypertrophic Myocardium
摘要
ObjectiveMyocardial hypertrophy is the high risk factor for heart failure, arrhythmia and sudden death.It has been demonstrated that Tanshinone could effectively inhibit the onset of myocardial hypertrophy, but the effect of Tanshinone on the electrophysiological abnormality in cellular membrane of hypertrophic myocardium is unknown.Methods The hypertrophic cardiomyocytes were isolated from hypertrophied left ventricles in 1K1C rats.Captopril(25 mg/kg by gavage) and or Tanshinone(10 mg/kg IP) were administered for 8 weeks after the 1K1C model being established for 6 weeks.By using patch clamp and intra-cellular calcium survey technique, the effect of Tanshinone and captopril on the action potential duration, L-type calcium current (I Ca,L) and intra-cellular calcium ion concentration in cellular membrane was investigated.ResultsTanshinone markedly shortens the prolongated action potential duration in hypertrophied myocytes (P0.001), decreases membrane capacity and peak amplitude of I Ca,L (P0.001). Moreover, Tanshinone significantly reduces intra-cellular calcium ion concentration, with no effect on the density of I Ca,L.ConclusionTanshinone not only reverses the myocardial hypertrophy, but also reduces calcium influx and shorten action potential duration which are beneficial to prevent arrhythmia.