Roca T P, Pigott J D, Clarkson C W, Crumb W J
Department of Pediatrics, Tulane University School of Medicine, New Orleans, Louisiana 70112-2699, USA.
Pediatr Res. 1996 Sep;40(3):462-8. doi: 10.1203/00006450-199609000-00016.
Animal studies have documented the presence of marked, species-dependent, developmental changes in the properties of the L-type calcium current in cardiac myocytes. In an effort to understand the postnatal changes which occur in the calcium current in human heart, we characterized the calcium current in atrial myocytes isolated from 17 pediatric and older children (ages 3 d to 14 y) and 12 adult (ages 43-79 y) human hearts using the whole-cell patch clamp technique. In contrast to animal models, we found no evidence for age-related changes in calcium current density, steady-state inactivation, or kinetics of recovery from inactivation, suggesting that, in human atrium, calcium channels are in many aspects functionally mature at the time of birth. However, statistically significant differences were found in the kinetics of calcium current inactivation, with calcium current measured in cells isolated from pediatric human atria inactivating approximately 2-fold faster than cells isolated from adult hearts. These results suggest a possible role for age-related changes in calcium current inactivation in the shortened action potential duration observed in pediatric compared with adult human atrium.
动物研究已证明，心肌细胞中L型钙电流的特性存在显著的、物种依赖性的发育变化。为了了解人类心脏钙电流在出生后发生的变化，我们使用全细胞膜片钳技术对从17名儿童及大龄儿童（年龄3天至14岁）和12名成人（年龄43 - 79岁）的心脏中分离出的心房肌细胞中的钙电流进行了表征。与动物模型不同，我们没有发现钙电流密度、稳态失活或失活恢复动力学存在与年龄相关变化的证据，这表明在人类心房中，钙通道在出生时在许多方面功能已成熟。然而，在钙电流失活动力学方面发现了统计学上的显著差异，从儿童人类心房分离的细胞中测得的钙电流失活速度比从成人心脏分离的细胞快约2倍。这些结果表明，与年龄相关的钙电流失活变化可能在儿童与成人心房相比观察到的动作电位时程缩短中起作用。
