Department of Pharmacology, Toho University Faculty of Pharmaceutical Sciences, Funabashi, Chiba 274-8510, Japan.
Eur J Pharmacol. 2010 Dec 15;649(1-3):263-7. doi: 10.1016/j.ejphar.2010.09.014. Epub 2010 Sep 19.
The effect of S(+)-efonidipine on sinus node action potential and calcium channel α-subunits was examined. The slope of the phase 4 depolarization of isolated rabbit sinus node tissue was significantly reduced by S(+)-efonidipine (1 μM), slightly reduced by nifedipine (1 μM), but was not affected by R(-)-efonidipine. S(+)-efonidipine (1 μM), inhibited the expressed Ca(V)1.2, Ca(V)1.3 and Ca(V)3.1 channel currents by 75.7%, 75.3% and 94.0%, nifedipine 84.0%, 43.2% and 14.9%, and R(-)-efonidipine 30.0%, 19.6% and 92.8%, respectively. Thus, the prolongation of the phase 4 depolarization of the rabbit sinus node by S(+)-efonidipine may be explained by blockade of the Ca(V)1.3 channel current.
研究了 S(+)-efonidipine 对窦房结动作电位和钙通道 α 亚基的影响。S(+)-efonidipine（1μM）显著降低了分离的兔窦房结组织 4 期去极化的斜率，硝苯地平（1μM）略有降低，但 R(-)-efonidipine 无影响。S(+)-efonidipine（1μM）抑制表达的 Ca(V)1.2、Ca(V)1.3 和 Ca(V)3.1 通道电流分别为 75.7%、75.3%和 94.0%，硝苯地平 84.0%、43.2%和 14.9%，而 R(-)-efonidipine 分别为 30.0%、19.6%和 92.8%。因此，S(+)-efonidipine 延长兔窦房结 4 期去极化可能是通过阻断 Ca(V)1.3 通道电流来解释的。
