灯盏花素对豚鼠心室肌细胞I_(Ca)的影响

目的观察灯盏花素对豚鼠心室肌单细胞钙离子电流(ICa)的影响。方法采用全细胞膜片钳制技术。结果灯盏花素能使豚鼠心室肌细胞ICa减小,连续刺激后,对ICa的抑制作用加强,与给药前比较,差异显著(P<0.01);此作用具有明显的电压依赖性,在峰电流电压下作用最明显,而对其反转电位无明显影响;灯盏花素对ICa的作用随质量浓度升高而加强,在指令电压0 mV时,5、10和20 mg.L-1灯盏花素使ICa分别减小5.4%、22.9%和45.0%(P<0.01),且可以恢复;在不同的刺激频率下,灯盏花素均可使ICa减小,尤其对高频率刺激细胞产生的ICa作用更明显(P<0.05)。结论灯盏花素能抑制豚鼠心室肌细胞的Ca2+内流,此作用具有电压依赖性、质量浓度依赖性、药物使用-刺激频率依赖性和可恢复性。

Effects of breviscapine on slow inward calium current in single ventricular cells of guinea pigs

Objective To investigate the effects of breviscapine on slow inward calium current(ICa)in single ventricular cells of guinea pigs.Methods Whole-cell patch clamp technique was used.Results Breviscapine could obviously decrease ICa in a way of concentration and voltage-dependent mode,but had little effect on reversal potential.Breviscapine with the concentration of 5 mg·L-1,10 mg·L-1,and 20 mg·L-1 decreased ICa by 5.4%,22.9% and 45.0%,respectively.When the stimulating frequency was changed,breviscapine facilitated the reduction of ICa through increasing clamp pulse frequency,and the inhibition of breviscapine was stronger at 0.5 s interval than that at 10 s.Conclusions Breviscapine decreases ICa in a voltage,concentration,use and frequency-dependence manner.