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目的研究酪氨酸激酶抑制剂染料木黄酮(GST)对豚鼠结肠平滑肌细胞L型钙通道电流的作用。方法木瓜蛋白酶法分离单个豚鼠结肠平滑肌细胞,应用全细胞式膜片钳技术记录L型钙通道电流。结果 GST(10 ~100μmo·lL-1)浓度依赖性地阻断L型钙通道电流,其作用可被洗脱,半数有效抑制浓度为(39.9±3.6)μmol·L-1。GST可使L型钙通道的稳态失活曲线向超极化方向左移约10 mV(P<0.01),对其斜率没有影响。GST的无活性拟似物大豆异黄酮对L型钙通道电流的作用明显小于GST。酪氨酸磷酸酶抑制剂原钒酸钠可阻断GST对钙通道电流的抑制作用。结论 GST可通过酪氨酸激酶途径抑制豚鼠结肠平滑肌L型钙通道。
Objective To investigate the effect of genistein (GST), a tyrosine kinase inhibitor, on L-type calcium current in guinea pig colon smooth muscle cells. Methods Single guinea pig colon smooth muscle cells were isolated by papain. Whole - cell patch clamp technique was used to record the L - type calcium current. Results GST (10-100μmol · L-1) blocked the L-type calcium current in a concentration-dependent manner. The effect of GST was eluted at a concentration of (39.9 ± 3.6) μmol·L-1. GST can shift the steady-state inactivation curve of L-type calcium channel to the left by about 10 mV (P <0.01) towards hyperpolarization without affecting its slope. GST inactive analogues soy isoflavones on the L-type calcium channel current was significantly less than the GST. Tyrosine phosphatase inhibitor sodium orthovanadate blocks the inhibitory effect of GST on calcium channel currents. Conclusion GST can inhibit the L-type calcium channel of guinea pig colonic smooth muscle through the tyrosine kinase pathway.