Inhibitory effects of dauricine on early afterdepolarizations and L-type calcium current

Canadian Journal of Physiology and Pharmacology
Qiang-Ni LiuFan-Dian Zeng

Abstract

We have previously reported that dauricine exerted antiarrhythmic effects on various experimental arrhythmias. To further clarify its mechanism, the effects of dauricine on action potential duration (APD), early afterdepolarizations (EADs), triangulation, which is defined as the repolarization time from APD at 30% level (APD30) to APD at 90% level (APD90), and L-type calcium current (I(Ca-L)) were studied using standard microelectrode techniques on rabbit papillary muscles and whole-cell patch clamp techniques on single myocytes isolated from rabbits by enzymatic digestion, respectively. Cardiac hypertrophy was induced by coarctating the abdominal aorta of rabbits. The results showed that in papillary muscles of hypertrophied rabbits, 1 micromol/L dofetilide, a selective IKr blocker, prolonged APD50 and APD90 and induced EADs (4/6, p < 0.01) with hypokalemia ([K+]o = 2.7 mmol/L). Dauricine inhibited EADs (p < 0.01) and shortened the prolonged APD (p < 0.01). In single myocytes, dauricine also inhibited EADs induced by dofetilide, hypokalemia, and hypomagnesaemia. Dauricine decreased the triangulation and reduced the peak amplitude of I(Ca-L) at all potentials tested. Dauricine shifted the steady-state activation curves to the r...Continue Reading

References

Mar 1, 2000·Journal of Cardiovascular Electrophysiology·L EckardtM Borggrefe
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Feb 28, 2007·Clinical and Experimental Pharmacology & Physiology·Zhi-Jiang HuangYin Dai

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Citations

Sep 17, 2011·Journal of Ethnopharmacology·Jing ZhaoShuangqing Peng
Mar 8, 2012·Molecules : a Journal of Synthetic Chemistry and Natural Product Chemistry·Bo ZhaoLian-Jun Guo
Jul 17, 2020·Journal of Traditional and Complementary Medicine·Ahmad BeikHamid Najafipour

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