Borgers M, Van Belle H
Basic Res Cardiol. 1985;80 Suppl 2:25-30.
The distribution of Ca2+ is assessed cytochemically in isolated rat hearts subjected to low Ca2+ environment with and without subsequent reexposure to normal external Ca2+. The same is done for isolated rat cardiac myocytes. The inclusion of 15 microM Ca2+ in the perfusate predisposes hearts to a partial paradox with increasing intensity towards the subepicardium. In affected areas, morphologically characterized by deviation of the lamina externa from the surface coat-sarcolemma and separation of some regions of the intercalated disk, the sarcolemma was devoid of Ca2+ deposits. Upon reperfusion, irreversible contracted cells with ruptured sarcolemma showed accumulation of Ca2+ precipitate in mitochondrial matrices. In non-affected cells (subendocardium) sarcolemmal Ca2+ was normal and mitochondria were virtually devoid of Ca2+ precipitate. Isolated myocytes were insensitive to Ca2+ deprivation and/or repletion and no Ca2+ shifts were demonstrated. These observations suggest a role for sarcolemma-bound Ca2+ in the integrity of this membrane.
在经历低钙环境且随后分别再次暴露于正常细胞外钙环境和未再次暴露于正常细胞外钙环境的离体大鼠心脏中，通过细胞化学方法评估钙离子（Ca2+）的分布情况。对离体大鼠心肌细胞也进行同样的操作。灌注液中加入15微摩尔钙离子会使心脏易出现部分矛盾现象，且朝着心外膜下方向强度增加。在受影响区域，其形态学特征为外膜偏离表面被膜 - 肌膜以及闰盘某些区域分离，肌膜上没有钙离子沉积。再灌注时，肌膜破裂的不可逆收缩细胞在线粒体基质中显示出钙离子沉淀的积累。在未受影响的细胞（心内膜下）中，肌膜钙离子正常，线粒体几乎没有钙离子沉淀。离体心肌细胞对钙离子剥夺和/或补充不敏感，未显示出钙离子转移。这些观察结果表明，与肌膜结合的钙离子在该膜的完整性中起作用。
