洛士辛对豚鼠心室肌细胞L型钙通道的作用

EFFECTS OF LOTUSINE ON L-TYPE CALCIUM CURRENTS IN GUINEA PIG VENTRICULAR CELLS

采用膜片钳技术 ,研究Lot对单个豚鼠心室细胞L型钙通道电流 (ICa -L)的影响。Lot1～ 2 0 0 μmol/L浓度依赖性地增加ICa -L幅值 ,EC50 为 38μmol/L ,Lot30 μmol/L使最大峰值电流增加 6 0 %。其促钙作用无明显使用依赖性 ,略促进钙通道电流激活 ,显著地减少钙电流的稳态失活。表明Lot增加L型钙电流作用主要与减少钙电流的稳态失活有关。

Lotusine (Lot), a pure alkaloid extracted from the green seed embry of Nelumbo nucifera Gaertn, was shown to possess positive inotropic effect on myocardium. In this paper, patch clamp techniques were used to study the effects of Lot on L-type calcium currents (ICa-L) in single ventricular myocyte of guinea pig. In whole cell recording mode, Lot 1～200 μmol·L -1 could does-dependently increase the amplitude of ICa-L with ED50 of 38μmol·L -1 and the increment of the peak ICa-L by 60%, but without the change of the potential of the maximum ICa-L . It was found that the effect of Lot possessed use-dependent. Lot 30μmol·L -1 slightly encouraged L-type calcium channel activation. Moreover, it significantly decreased the channel deactivation. The results suggested that the main manner of enhancement of L-type calcuim current of Lot may be related to delay of L-type calcium channel inactive.