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本实验用全细胞膜片钳技术观察三羟异黄酮(genistein,GST)对豚鼠心室肌细胞L-钙通道电流(ICa、L)的影响。结果如下:(1)GST(10、50、100 μmol/L)可浓度依赖性地降低ICa,L(n=6,P<0.01)。GST的非活性结构类似物daidzein(100μmol/L),在同一浓度范围对ICa,L没有影响(n=5,P>0.05)。(2)GST使I-V曲线上移,但对ICa,L的电压依赖特征和最大激活电压无明显影响。(3)GST对ICa,L的激活动力学特性也无影响,但可使钙电流稳态失活曲线左移。V0.5从对照的-28.6±0.6 mV变为-32.8±1.1mV,κ值从对照的5.8±0.5 mV升至6.5±0.9 mV(n=6,P<0.05)。(4)GST明显使复活曲线右移,从而使ICa,L从失活状态下恢复明显减慢(n=7,P<0.01)。(5)酪氨酸磷酸酶抑制剂正钒酸钠(1 mmol/L)显著对抗GST引起的ICa,L抑制效应(n=6,P<0.01)。根据以上结果得出的结论是:GST抑制ICa,L加速钙通道失活和钙通道在失活状态下恢复减慢;GST对ICa,L的这种抑制作用与蛋白酪氨酸激酶(PTK)抑制有关。
In this study, whole-cell patch clamp technique was used to observe the effect of genistein (GST) on L-calcium channel currents (ICa, L) in guinea pig ventricular myocytes. The results are as follows: (1) GST (10, 50, 100 μmol/L) can decrease ICa,L (n=6, P<0.01) in a concentration-dependent manner. The inactive structural analogue daidzein (100 μmol/L) of GST had no effect on ICa,L in the same concentration range (n=5, P>0.05). (2) GST shifts the I-V curve upward, but has no significant effect on the voltage dependence characteristics and maximum activation voltage of ICa, L. (3) GST had no effect on the activation kinetics of ICa, L, but left the calcium current inactivation curve to the left. V0.5 was changed from -28.6±0.6 mV in the control to −32.8±1.1 mV, and the κ value was increased from 5.8±0.5 mV in the control to 6.5±0.9 mV (n=6, P<0.05). (4) GST significantly shifted the resuscitation curve to the right, resulting in a significant slowing of ICa,L recovery from an inactive state (n=7, P<0.01). (5) The tyrosine phosphatase inhibitor sodium orthovanadate (1 mmol/L) significantly inhibited the inhibitory effect of GST on ICa,L (n=6, P<0.01). Based on the above results, the following conclusions are drawn: GST inhibits ICa, L accelerates inactivation of calcium channels and calcium channels are slowed down in the inactive state; GST inhibits ICa,L and this protein tyrosine kinase (PTK) Suppression related.