镁对心脏兴奋-收缩偶联的影响。

Effects of magnesium on cardiac excitation-contraction coupling.

作者信息

Michailova Anushka P, Belik Mary Ellen, McCulloch Andrew D

机构信息

Department of Bioengineering, PFBH 241, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0412, USA.

出版信息

J Am Coll Nutr. 2004 Oct;23(5):514S-517S. doi: 10.1080/07315724.2004.10719392.

DOI:10.1080/07315724.2004.10719392

PMID:15466954

Abstract

OBJECTIVE

Magnesium regulates a large number of cellular processes. Small changes in intracellular free Mg(2+) (Mg(2+)) may have important effects on cardiac excitability and contractility. We investigated the effects of Mg(2+) on cardiac excitation-contraction coupling.

METHODS

We used our ionic-metabolic model that incorporates equations for Ca(2+) and Mg(2+) buffering and transport by ATP and ADP and equations for MgATP regulation of ion transporters (Na(+)-K(+) pump, sarcolemmal and sarcoplasmic Ca(2+) pumps).

RESULTS

Model results indicate that variations in cytosolic Mg(2+) level might sensitively affect diastolic and systolic Ca(2+), sarcoplasmic Ca(2+) content, Ca(2+) influx through L-type channels, efficiency of the Na(+)/Ca(2+) exchanger and action potential shape. The analysis suggests that the most important reason for the observed effects is a modified normal function of sarcoplasmic Ca(2+)-ATPase pump by altered diastolic MgATP levels.

CONCLUSION

The model is able to reproduce qualitatively a sequence of events that correspond well with experimental observations during cardiac excitation-contraction coupling in mammalian ventricular myocytes.

摘要

目的

镁调节大量细胞过程。细胞内游离镁离子（Mg(2+)）的微小变化可能对心脏兴奋性和收缩性产生重要影响。我们研究了Mg(2+)对心脏兴奋-收缩偶联的影响。

方法

我们使用了离子代谢模型，该模型纳入了ATP和ADP对Ca(2+)和Mg(2+)的缓冲及转运方程，以及离子转运体（Na(+)-K(+)泵、肌膜和肌浆网Ca(2+)泵）的MgATP调节方程。

结果

模型结果表明，胞质镁离子水平的变化可能敏感地影响舒张期和收缩期Ca(2+)、肌浆网Ca(2+)含量、通过L型通道的Ca(2+)内流、Na(+)/Ca(2+)交换体的效率和动作电位形态。分析表明，观察到这些效应的最重要原因是舒张期MgATP水平改变导致肌浆网Ca(2+)-ATP酶泵的正常功能发生改变。