前胡丙素对培养新生鼠心肌细胞自发性[Ca^(2+)]_i瞬间变化的影响(英文)

Effect of praeruptorin C on spontaneous [Ca 2+ ] i transients in cultured myocardial cells of neonatal rats

目的：研究前胡丙素（ＰｒａＣ）的心脏负性肌力作用的机制．方法：使用Ｃａ２＋敏感的荧光指示剂Ｆｕｒａ２ＡＭ，在培养的新生鼠心肌细胞测定细胞内Ｃａ２＋的瞬间变化．结果：ＰｒａＣ１０、３０μｍｏｌ·Ｌ－１引起［Ｃａ２＋］ｉ瞬间变化最大值明显减少．ＰｒａＣ１０，３０μｍｏｌ·Ｌ－１能部分抑制ＣａＣｌ２４８ｍｍｏｌ·Ｌ－１及Ｂａｙｋ８６４４１００ｎｍｏｌ·Ｌ－１增加的［Ｃａ２＋］ｉ瞬间变化的峰值，但对［Ｃａ２＋］ｉ瞬间变化的基线水平没有明显的影响．Ｒｙａｎｏｄｉｎｅ３μｍｏｌ·Ｌ－１使［Ｃａ２＋］ｉ瞬间变化的幅度明显降低，在此基础上，ＰｒａＣ３０μｍｏｌ·Ｌ－１继续抑制［Ｃａ２＋］ｉ的瞬间变化．结论：ＰｒａＣ在完整心肌的负性肌力作用可能与其部分抑制兴奋收缩偶联过程中的Ｃａ２＋内流有关．

AIMS: To study the effects of praeruptorin C (Pra-C) on [Ca2+](i) transients in cultured neonatal myocardiocytes. METHOD: Using Ca2+-sensitive fluorescent indicator, Fura 2-AM, spontaneous cytosolic Ca2+ transients were measured in cultured myocardial cells of neonatal rats. RESULTS: Pra-C 10, 30 mu mol . L(-1) caused a decrease in the peak of Ca2+ transients. Pra-C 30 mu mol . L(-1) and 10 - 30 mu mol . L(-1) inhibited partly the stimulatory effects of CaCl2 4.8 mmol . L(-1) and Bay k 8644 100 nmol . L(-1) on peak Ca2+ transients, respectively. Pra-C did not cause any marked change in the basal [Ca2+](i) level between beats. Pra-C inhibited the reduced [Ca2+](i) transients after inhibition of sarcoplasmic reticulum Ca2+ release in ryanodine pretreated cells. CONCLUSIONS: Pra-C inferred with the Ca2+ influx responsible for excitation-contraction coupling in myocardiocytes.