Antifibrillatory effect of berberine
Abstract
Berberine (Ber 1 mg/kg iv), a quaternary ammonium alkaloid, distinctly elevated the ventricular fibrillation threshold(159+/-41%) to electrical stimulation in anesthetized cats.
It increased the duration of action potential (APD) at 20% and 90% of repolization (APD20, APD90) and effective refractory period (ERP) of isolated guinea pig papillary muscles. These effects appeared 1 min after exposure to Ber and reached a steady state within 20 min. Ber prolonged APD90 and ERP by a maximum of 53+/-25% and 63+/-35%, respectively. EC50 was 22 microM. These effects were abolished after Ber was washed out with Tyrode’s solution in 30 min. Associated with the prolongation of APD and ERP, the isometric contractile force of the preparation was increased, but no changes in resting potential, amplitude and maximal upstake velocity of the action potential were seen in the presence of Ber.
Keywords:
It increased the duration of action potential (APD) at 20% and 90% of repolization (APD20, APD90) and effective refractory period (ERP) of isolated guinea pig papillary muscles. These effects appeared 1 min after exposure to Ber and reached a steady state within 20 min. Ber prolonged APD90 and ERP by a maximum of 53+/-25% and 63+/-35%, respectively. EC50 was 22 microM. These effects were abolished after Ber was washed out with Tyrode’s solution in 30 min. Associated with the prolongation of APD and ERP, the isometric contractile force of the preparation was increased, but no changes in resting potential, amplitude and maximal upstake velocity of the action potential were seen in the presence of Ber.