粉防己碱对培养乳鼠心肌细胞内游离钙的影响

Effects of tetrandrine on cytosolic free Ca￣(2+) in cultured myocardial cells of neonatal rats

目的：观察粉防己碱（Ｔｅｔ）对培养大鼠心肌细胞内游离钙（［Ｃａ￣（２＋）］ｉ）的影响。方法：运用Ｃａ￣（２＋）指示剂Ｆｕｒａ－２作为细胞内钙离子的荧光探针，利用ＡＲ－ＣＭ－ＭＩＣ阳离子测定系统，检测培养乳鼠心肌细胞内游离钙的浓度（［Ｃａ￣（２＋）］ｉ）。结果：在细胞外液钙浓度为１．８ｍｍｏｌ／Ｌ时，心肌细胞静息［Ｃａ￣（２＋）］ｉ为８０．３±６．９ｍｍｏｌ／Ｌ。在细胞外液钙浓度为１．８～５．４ｍｍｏｌ／Ｌ时，粉防己碱（Ｔｅｔ）对细胞静息［Ｃａ￣（２＋）］ｉ无明显影响。Ｔｅｔ１～１００μｍｏｌ／Ｌ剂量依赖的抑制高钾和Ｈ＿２Ｏ＿２引起的［Ｃａ￣（２＋）］ｉ的升高，Ｔｅｔ１０μｍｏｌ／Ｌ能对抗去甲肾上腺素引起的［Ｃａ￣（２＋）］ｉ升高。对搏动细胞，Ｔｅｔ能抑制细胞外高钙引起的收缩期［Ｃａ￣（２＋）］ｉ瞬间的变化，减慢搏动频率。结论：Ｔｅｔ对高Ｋ￣＋、去甲肾上腺素、Ｈ＿２Ｏ＿２及高钙引起的［Ｃａ￣（２＋）］ｉ增高的抑制作用可能是其抗心肌缺血机理之一。

OBJECTIVE: To observe the effects of tetrandrine on cytosolic free Ca2+ in cultured myocardial cells of neonatal rats.METHODS:Intracellular free calcium concentration([Ca2+]i)was measured with Ca2+-sensitive fluorescent indicator,Fura-2/AM in cultured myocardial cells of neonatal rats using AR-CM-MIC cation measurement system. RESULTS:Resting[Ca2+]i was 80.3±6.9 nmol/L in the presence of Ca2+ 1.8 mmol/L in Hank's solution. Tetrandrine(Tet)had no effect on the resting [Ca2+]i when extracellular Ca2+was 1.8～5.4 mmol/L. Tet 1 ～100 μmol/L concentration-dependently inhibited K+and H2O2 induced [Ca2+]i elevation. Tet 10μmol/L inhibited norepinephrine induced[Ca2+]i elevation. Tet10.30μmol/L caused a decrease in the peak of Ca2+ transient and inhibited partly the stimulatory effect of CaCl2 4.8 mmol/L.CONCLUSION:The results showed that the inhibitory effects of Tet on KCl,norepinephrine and H2O2 induced[Ca2+]i elevation were one of its mechanism for anti-myocardial ischemia.