Effects of <i>Leonurine</i> on L-Type Calcium Channel in Rat Ventricular Myocytes

Abstract

Leonurine (Leo) is a special alkaloid principle of Herba leonuri that has recently been suggested to improve cardiovascular functions. To date, there is no direct ionic evidence of Leo on regulating calcium channels in the heart. In the present study, we examined the effects of Leo on action potentials and membrane currents recorded from isolated rat ventricular myocytes with the whole-cell patch clamp technique. Leo 100 µM shortened the action potential duration in a dose-dependent manner. Leo up to 200 µM had no significant effect on the Na current (I Na ) and K current (I K ). However, Leo depressed the L-type Ca 2 current (I Ca,L ). In the presence of 20 and 100 µM Leo, the current density was decreased and the voltage at half maximal inactivation V 0.5 shift to more negative potential. The recovery time constant was also delayed. In addition, the transcription and protein expression levels of L-type calcium channel (Ca v1.2 ) in primary cultured neonatal myocytes from Sprague-Dawley rats were reduced by Leo treatment in a dose-dependent fashion as assessed by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot assays. We conclude that Leo inhibits L-type calcium channels in cardiomyocytes.

Leonurine pretreatment protects the heart from myocardial ischemia-reperfusion injury

“…Previous studies have demonstrated that SCM-198 ameliorates atherosclerosis, inhibits osteoclastogenesis, and prevents osteoporosis. 32–34 Consistent with the previous studies, 35,36 our findings demonstrated that SCM-198 could increase the heart rate, ±dp/dt max , Vpm, and L0. In vivo , we observed that SCM-198 reduced the infarct size, which was recognized to be one of the frequently used clinical end-points to predict clinical outcomes.…”

Leonurine, a Potential Agent of Traditional Chinese Medicine: Recent Updates and Future Perspectives

“…Xin et al [9] found that leonurine could reduce I Ca,L , and the LTCCα 1C subunit down-regulation might contribute to altered calcium handling in leonurine-treated cardiomyocytes. Leonurine at 100 μM shortened the action potential duration in a dose-dependent manner.…”