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目的：探讨内皮素－１（ＥＴ－１）对心肌细胞内游离钙浓度（［Ｃａ２＋］ｉ）的作用以及不同浓度ＥＴ－１引起［Ｃａ２＋］ｉ升高作用的量效关系。方法：采用分离的Ｓｐｒａｇｕｅ－Ｄａｗｌｅｙ大鼠心室肌细胞，以Ｆｕｒａ－２／ＡＭ荧光指示剂负载，检测不同浓度ＥＴ－１引起［Ｃａ２＋］ｉ变化。结果：ＥＴ－１引起［Ｃａ２＋］ｉ升高呈双相反应，即起始的短暂快速相和随后的持续相。在１×１０－９～５×１０７ｍｏｌ／Ｌ范围内，随着ＥＴ－１浓度的增加，其升高［Ｃａ２＋］ｉ的作用亦增强；并且这种作用可被ＥＴＡ的特异性受体阻断剂ＢＱ１２３（２×１０６ｍｏｌ／Ｌ）所阻断。结论：ＥＴ－１升高［Ｃａ２＋］ｉ呈剂量依赖关系，其作用具有特异性，并且是通过ＥＴＡ受体介导的。
AIM: To investigate the effect of endothelin-1 (ET-1) on intracellular free calcium concentration ([Ca2 +] i) and the effect of ET-1 on [Ca2 +] i concentration. Methods: Isolated Sprague-Dawley rat ventricular myocytes were loaded with Fura-2 / AM fluorescent indicator to detect the changes of [Ca2 +] i induced by different concentrations of ET-1. Results: ET-1 induced a [Ca2 +] i increase in biphasic response, ie, an initial transient fast phase followed by a sustained phase. In the range of 1 × 10-9 ~ 5 × 107mol / L, the effect of increasing [Ca2 +] i was also enhanced with the increase of ET-1 concentration, and this effect could be enhanced by ETA-specific receptor Blocker BQ123 (2 × 10 6mol / L) blocked. CONCLUSION: Elevated ET-1 [Ca2 +] i in a dose-dependent manner is specific and is mediated through ETA receptors.