RESUMO
Objective To explore the effect of dronedaronel on hyperpolarization-activated cyclic-nucleotide-gated(HCN) channel expression by detecting the change of HCN channel mRNA and protein level before and after giving dronedarone in neonatal rat ventricular myocytes.Methods Neonatal rat ventricular myocytes were separated and digested by type Ⅱ collagenase,and then single ventricular myocytes were collected through differential sticking wall separation method.According to the concentrations (0.1,0.5,1.0,5.0,10.0,20.0 μmol/L of dronedaronel for treating myocytes for 48 h) and time(10 μmol/L of dronedaronel for treating myocytes for 1,6,12,24,48 h)the gradient grouping was conducted.The levels of HCN2 and HCN4 channel mRNA and protein level were determined by real-time PCR and Western blot.Results The HCN2 mRNA and HCN4 mRNA expression levels in concentration gradient group and time gradient group were lower than those in the control group(P＜0.05);compared with the control group,the protein level in the 10 umol/L dronedaronel treatment for 12 h group was significantly down-regulated(P＜ 0.01).Conclusion Dronedaronel could inhibit the expression of HCN2/HCN4 channel mRNA and protein,moreover its action shows the concentration dependency and reaches the maximum at 12 h after medication.
RESUMO
Alkaloid is one of the main antineoplastic activities in Chinese Herbal Medicine.There has been big progress on the mechanism of antitumor in natural alkaloids and their derivatives in recent years,especially focusing on the targets of hypoxia inducible factor 1,telomere,and topoisomerase.The new trends of these three targets have been reviewed in this paper.