低浓度双氢哇巴因对豚鼠心室肌细胞内游离钙浓度的影响(英文)

Effects of low concentration of dihydroouabain on intracellular calcium in guinea pig ventricular myocytes

用激光共聚焦显微镜检查研究低浓度双氢哇巴因 (DHO)对豚鼠心室肌细胞内钙浓度 ([Ca2 + ]i)的影响。DHO 1fmol/L～ 1mmol/L可增加心室肌细胞的 [Ca2 + ]i,尤其以 10 pmol/LDHO为显著。Nisoldipine、EG TA或TTX可分别部分抑制 10 pmol/LDHO的作用。去除胞外K+ 和Na+ 后 ,上述作用仍存在。以上结果表明 ,低浓度DHO可通过激活钙通道和TTX敏感的钠通道 ,或许还可直接促进胞内钙释放来增加 [Ca2 + ]i,并有不依赖Na+ /K+ 泵而升高 [Ca2 +

The effects of low concentration of dihydroouabain (DHO) on intracellular calcium concentration ([Ca 2+ ] i) were investigated in guinea pig ventricular myocytes. [Ca 2+ ] i was detected by confocal microscopy and represented by fluorescent intensity. DHO (1 fmol/L～1 mmol/L) increased [Ca 2+ ] i, especially at 10 pmol/L. Nisoldipine, egtazic acid, or tetrodotoxin partially inhibited the effect of 10 pmol/L DHO on [Ca 2+ ] i. The effects of DHO remained in the absence of extracellular K + and Na +. These results suggest that low concentration of DHO might increase [Ca 2+ ] i via the receptor operated Ca 2+ channels, TTX sensitive Na + channels or/and triggering of intracellular calcium release; Na +/K + pump and Na +/Ca 2+ exchange seem not involved in the effect of DHO.