牛磺酸对心肌细胞核钙转运功能异常的保护

目的：为观察异丙肾上腺素（ISO）致大鼠心肌缺血损伤时心肌细胞核钙转运功能的异常变化及牛磺酸对其影响。方法：给Wistar大鼠皮下注射5mg/kgISO液，造成心肌缺血损伤模型。超速离心分离纯化心肌细胞核。酶学方法鉴定核纯度和测定核膜Ca^2 -ATP酶活性，同位素法观测核钙的摄取。结果：与正常对照组比较，心肌缺血组（实验组）心肌细胞核膜Ca^2 依赖性ATP酶活性降低18．1％（P＜0．05）,^45Ca^2 摄取效率也显著降低，其最反应速度（Vmax)降低56.4％，细胞核心Ca^2 依赖性ATP酶的最大反应速度（Vmax)降低33．0％（P＜0．05）。平衡常数（Km)降低42．8％（P＜0．01）。牛磺酸保护组心肌细胞核Ca^2 －ATP酶活性及核^45Ca^2 摄取与正常对照组比较均未见显著性改变。结论：牛磺酸对ISO致大鼠心肌缺血损伤时心肌细胞钙转运功能降低有保护作用。

Effects of Taurine on Dysfunction of Myocardial Nuclear Calcium Transport

Objective: To observe the dysfunction of myocardial nuclear calcium transport in rat myocardial injury and the effects of taurine on it. Methods: The model of myocardial damage was induced by subcutaneous injection of isoproterenol (ISO,5 mg/kg day).Myocardial nuclei were purified with sucrose density centrifugation and identified zymologically. The activity of Ca 2 _ATPase was measured zymologically and calcium uptake was assayed with 45 a 2 isotope. Results: Compared with the control,the Ca 2 _ATPase activity of myocardial nuclear membrane in ischemia group(exprimental) was decreased by 18.1% (P<0.05),the nuclear 45 Ca 2 uptake was significantly decreased and V max value was lowered by 54.6%. V max and K m of ATPase activity decreased by about 33.0% (P<0.05) and 42.8%(P<0.01) respectively. Compared with the control,Ca 2 _ATPase activity and 45 Ca 2 uptake in the myocardial nuclei of the taurine group showed no significant changes. Conclusion: The above results indicated taurine has notable protective effects on dysfunction of nuclear calcium transport in rat myocardium.