Effect ofα-Allocryptopine on Delayed Afterdepolarizations and Triggered Activities in Mice Cardiomyocytes Treated with Isoproterenol

Objective . To investigate the effect of α -allocryptopine (ALL) on delayed afterdepolarization (DAD) incidence and triggered activity (TA) in mice administered isoproterenol (ISO). Methods . Mouse ventricular myocytes were isolated. And the cellular electrophysiological properties of ventricular myocytes were investigated. Results . We found that the incidences of DADs and TA in mouse myocytes were increased by ISO treatment. In sharp contrast, triggered arrhythmia events were rarely observed in myocytes with 10 μ M ALL treatment. Transient inward current (Iti) was reduced significantly with ALL treatment, which contributed to DAD-related triggered arrhythmia. Compared to Iso-treated group, the L-type calcium current (ICa,L) densities were decreased after exposure to ALL, along with slower activation, quicker inactivation, and longer time constant of recovery from inactivation kinetics. Conclusion . There is less triggered arrhythmia events in ventricular myocytes treated with ALL. This effect may be associated with the inhibition ofItiandICa,L.