DEVELOPMENTAL-CHANGES IN CARDIAC MYOCYTE CALCIUM REGULATION
DEVELOPMENTAL-CHANGES IN CARDIAC MYOCYTE CALCIUM REGULATION
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DOI：
10.1161/01.res.67.3.574
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发表时间：
1990-09-01
影响因子：
20.1
通讯作者：
KLITZNER, TS
中科院分区：
文献类型：
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作者：
CHIN, TK;FRIEDMAN, WF;KLITZNER, TS
在新生儿（1-7天）和成年（8-10周）新西兰白色兔的分离心室肌细胞中评价了经肌膜Ca 2+内流和细胞内储存位点Ca 2+释放对心肌收缩贡献的发育变化。收缩停止在一个节拍时，细胞外Ca 2+从1 mM降低到微摩尔水平，使用快速灌注技术。在再灌注1 mM Ca 2+，控制收缩幅度的恢复发生在新生儿心肌细胞与成人心肌细胞相比，显着较少的节拍后，1分钟后相比，5分钟的减少Ca 2+。在用1或10 μ M ryanodine灌注15分钟后，两个年龄组的收缩幅度都降低，但成人的降低幅度明显大于新生儿。这些实验表明，分离的心室肌细胞可用于细胞内Ca 2+调节的发育变化的研究。 结果表明，新生儿心脏收缩相对更依赖于跨肌膜Ca ~（2+）内流。此外，虽然从细胞内储存位点释放的Ca 2+存在于新生儿和成人中，但其在心脏收缩中的作用在成人中更显着。
Developmental changes in the contributions of transsarcolemmal Ca2+ influx and Ca2+ release from intracellular storage sites to myocardial contraction were evaluated in isolated ventricular myocytes from neonatal (aged 1-7 days) and adult (aged 8-10 weeks) New Zealand White rabbits. Contractions ceased in one beat when extracellular Ca2+ was decreased from 1 mM to micromolar levels using a rapid perfusion technique. On reperfusion with 1 mM Ca2+, recovery of control contraction amplitude occurred after significantly fewer beats in neonatal myocytes compared with adult myocytes, and after 1 minute compared with 5 minutes of reduced Ca2+. After 15 minutes of perfusion with either 1 or 10 .mu.M ryanodine, contraction amplitude decreased in both age groups, but the decrease was significantly greater in adults than in neonates. These experiments indicate that isolated ventricular myocytes may be used in the study of developmental changes in intracellular Ca2+ regulation. Results suggest that cardiac contraction in neonates is relatively more dependent on transsarcolemmal Ca2+ influx. Furthermore, although Ca2+ release from intracellular storage sites is present in both neonates and adults, its role in cardiac contraction is more significant in adults.