This fraction and the ethanol extract from green tea were also able to induce the expression of hyperpolarizationactivated cyclic nucleotide-gated channel 4 (HCN4), the important factor for automatic beating of SAN, but insignificantly (P > ). In conclusion, neonatal cardiomyocytes were isolated and suitable for use as a model for screening of pacemaker cell transduction effects of potential candidates. From this study, the garlic ethyl acetate fraction presented as the most promising nominee for further neonatal cardiomyocyte transdifferentiating effects. | Primary study for possible transdifferentiation effects of several Vietnamese plant extracts on isolated rat neonatal cardiomyocytes