Ca depletion and repletion in rat heart: age-dependent changes in the sarcolemma.
Ca depletion and repletion in rat heart: age-dependent changes in the sarcolemma.
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大鼠心脏中 Ca 的消耗和补充：肌膜的年龄依赖性变化。
DOI：
10.1152/ajpheart.1983.245.2.h343
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发表时间：
1983
期刊：
影响因子：
--
通讯作者：
Rich,TL
中科院分区：
文献类型：
--
作者：
Frank,JS;Rich,TL
Chizzite和Zak(Science 213：1508-1511,1981)已经证明，用无钙介质灌流的大鼠心脏对钙悖论表现出年龄相关的反应。6d以下，心脏对钙耗竭不敏感。到15天时，心脏对钙的消耗变得敏感，通过肌挛缩的发展和返回钙时细胞内酶的释放来监测。本研究比较了新生大鼠和成年大鼠在钙耗竭和耗竭后细胞表面的结构。我们的目的是观察糖唇(表面被膜-外板)层的分离是否与钙悖论的年龄相关性有关。兰登多夫灌流3天的心脏，暴露于低于10(-8)MCa的20分钟内，95%的细胞中有完整的糖基化反应。到20天时，在所有被检查的细胞(40个)中，心脏之间已有超过38.5+/-1.6%的糖萼层分离。成人心脏有65.9+/-4.6%的心脏表面有外层分离。作为完整膜通透性的细胞化学探针的镧(La)在钙耗竭和再充盈后3天的心脏中被排除在细胞质之外。另一方面，出生20至26天的大鼠心脏胞浆内有镧沉积。此外，在钙耗竭和再耗竭后，细胞内酶(肌酸激酶)的释放在3日龄时几乎可以忽略不计，但在22日龄时上升到1152+/-163IU/g干重。细胞表面超微结构变化的发展与新生儿对钙丢失的功能敏感性增加的模式之间的平行关系支持了糖萼在钙通透性调节中的作用的观点。
It has been shown by Chizzonite and Zak (Science 213:1508-1511, 1981) that rat hearts perfused with calcium (Ca)-free medium exhibit an age-dependent response to the Ca paradox. Below 6 days the hearts were insensitive to Ca depletion. By 15 days the hearts developed a sensitivity to Ca depletion monitored by the development of contracture and release of intracellular enzymes on return to Ca. The present study compared the structure of the cell surface in the neonatal rat and the adult rat after Ca depletion and repletion. Our aim was to see if separation of the layers of the glycocalyx (surface coat-external lamina) correlated with the age dependence of the Ca paradox. Langendorff-perfused 3-day hearts exposed for 20 min to less than 10(-8) M Ca had an intact glycocalyx in 95% of their cells. By 20 days the hearts had separation between layers of glycocalyx over 38.5 +/- 1.6% of their surface in all cells (40) examined. Adult hearts had separation of external lamina in 65.9 +/- 4.6% of their surface. Lanthanum (La) used as a cytochemical probe for intact membrane permeability was excluded from the cytoplasm of 3-day hearts after both Ca depletion and repletion. Twenty- to 26-day-old hearts on the other hand had La deposits throughout the cytoplasm. In addition, intracellular enzyme release (creatine kinase) after Ca depletion and repletion was negligible at 3 days but rose to 1,152 +/- 163 IU/g dry wt for 22-day-old hearts. The parallelism between the development of ultrastructural changes in the cell surface and the pattern of increasing functional sensitivity to Ca loss in the neonate supports the idea of a role for the glycocalyx in the regulation of Ca permeability.