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目的研究黄芪甲苷(astragaloside IV,AS-IV)对豚鼠心室肌细胞L型钙电流和细胞内钙的影响。方法分离单个豚鼠心室肌细胞,应用全细胞膜片钳技术测定钙电流,并采用荧光显微镜CCD成像系统动态观察细胞内钙(intracellular calcium concentration,[Ca2+]i)变化。结果 1×10-6mol·L-1AS-IV可明显抑制I Ca-L,使最大电流峰值降低32.6%。AS-IV对60 mmol·L-1KCl诱导的[Ca2+]i升高有抑制作用,最大荧光密度变化值从1.17±0.30(n=6)降低到0.26±0.16(n=5,P<0.05)。AS-IV可直接促进钙池内钙释放,使[Ca2+]i从0.08±0.02(n=10)升高到0.23±0.07(n=8,P<0.05)。结论 AS-IV抑制L型钙通道,可减少细胞外钙内流;同时它促进内钙释放,对心肌细胞内钙稳态表现为双向调节作用。
Objective To investigate the effects of astragaloside IV (AS-IV) on L-type calcium currents and intracellular calcium in guinea pig ventricular myocytes. Methods Single guinea pig ventricular myocytes were isolated and whole cell patch clamp technique was used to measure the calcium current. The changes of intracellular calcium concentration ([Ca2 +] i) were observed dynamically by fluorescence microscopy CCD imaging system. Results 1 × 10-6 mol·L-1AS-IV significantly inhibited I Ca-L and decreased the maximum current peak by 32.6%. AS-IV inhibited the increase of [Ca2 +] i induced by 60 mmol·L-1 KCl, and the maximum fluorescence density decreased from 1.17 ± 0.30 (n = 6) to 0.26 ± 0.16 (n = 5, . AS-IV directly promoted calcium release from the calcium pool, increasing [Ca2 +] i from 0.08 ± 0.02 (n = 10) to 0.23 ± 0.07 (n = 8, P <0.05). Conclusion AS-IV inhibits the L-type calcium channel and decreases the influx of extracellular calcium. Simultaneously, it promotes the release of intracellular Ca (superscript 2 +) and plays a bidirectional role in the regulation of intracellular calcium homeostasis.