氧化苦参碱对豚鼠单个心室肌细胞胞浆[Ca^(2+)]_i的影响

Effect of oxymatrine on [Ca^(2+) ]_i in single ventricular myocyte of guinea pig

目的 观察氧化苦参碱对急性分离的豚鼠单个心室肌细胞内游离钙离子浓度([Ca2+]i)的影响。方法 采用酶解法分离豚鼠单个心肌细胞,用钙敏感的荧光指示剂Fluo-3/AM染色,以荧光强度(FI)来代表[Ca2+]i,应用激光扫描共聚焦显微技术动态监测FI的变化。结果 在静息状态下,10μmol·L-1氧化苦参碱对[Ca2+]i无明显影响;但10 μmol·L-1氧化苦参碱对60mmol·L-1KCl介导的外钙内流却有明显抑制作用(P<0.05)。结论 氧化苦参碱对电压依赖性钙通道(VDC)具有明显抑制作用,这可能是其抗心律失常作用机制之一。

OBJECTIVE: To observe the effect of oxymatrine on intracellular calcium concentration ([Ca2+]i) in freshly isolated ventricular cell of guinea pig. METHODS: An enzymatic method was used to isolate single cardiomyocyte of guinea pig. The isolated cardiomyocyte was placed in Tyrode solution containing Ca2+ 1.8 mmol&middotL-1 or Ca 2+-free solution containing EGTA 2 mmol&middotL-1 and loaded with Ca2+-sensitive fluorescent indicator Fluo-3/AM. [Ca 2+]i represented by fluorescent intensity (FI) was measured by laser scanning confocal microscope (LSCM). RESULTS: At resting levels, [Ca2+]i was not affected by 10 μmol&middotL-1 oxymatrine. However, 10 μmol&middotL -1 oxymatrine obviously inhibited the Ca2+ influx induced by KCl 60 mmol&middotL-1 (P < 0.05). CONCLUSION: Oxymatrine showed significant inhibition of voltage-dependent channel (VDC), which may be one of the mechanisms of counteracting arrhythmia.