Regulation of cardiac muscle contraction by intracellular Ca2+.
Regulation of cardiac muscle contraction by intracellular Ca2+.
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细胞内 Ca2 调节心肌收缩。
DOI：
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
S. Kurihara
中科院分区：
文献类型：
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作者：
S. Kurihara
在这篇简短的评论中，我们一直在研究的哺乳动物心肌细胞内Ca 2+瞬变和收缩的影响因素进行了讨论。根据Blinks [6]提出的方案，关于[Ca 2 +]i变化和收缩的过程分为三个步骤：上游，中央和下游。然而，这些进程是相互关联的。虽然Ca 2+瞬变是触发收缩的重要步骤，但它受到以下中枢和下游机制的影响。本文讨论了完整标本中收缩元件（中枢机制）的Ca ~（2+）敏感性的评价，测定强直收缩时[Ca ~（2+）]i与张力的关系是可能的方法之一。Ca 2+与肌钙蛋白C结合的变化是确定Ca 2+敏感性的重要因素，但也认为涉及其他机制。在心肌中，从下游（特别是跨桥连接和分离）到中央过程的反馈机制是确定收缩特性的生理学重要机制。这种反馈机制通过改变肌钙蛋白-C对Ca 2+的亲和力来影响细胞内Ca 2+瞬变。因此，对测得的Ca 2+瞬变的解释并不简单，必须考虑所涉及的众多因素。进一步的研究是必要的，以阐明的分子机制，是负责反馈的下游机制，中央和上游机制。
In this short review, some of the factors which influence the intracellular Ca2+ transients and contraction in mammalian cardiac muscles which we have been examining are discussed. The processes concerning the change in [Ca2+]i and contraction are divided into three steps following the scheme proposed by Blinks [6]: Upstream, Central, and Downstream. However, these processes are interrelated. Although the Ca2+ transient is an important step for triggering contraction, it is influenced by the following Central and Downstream mechanisms. The evaluation of Ca2+ sensitivity of the contractile elements (Central mechanism) in intact preparations is discussed; measurement of the relation between [Ca2+]i and tension in tetanic contraction is one of the possible methods. A change in the Ca2+ binding to troponin-C is an important factor to determine the Ca2+ sensitivity but other mechanisms are also considered to be involved. In cardiac muscles, the feedback mechanism from the Downstream, in particular the cross-bridge attachment and detachment, to the Central processes is a physiologically important mechanism in the determination of contractile properties. This feedback mechanism alternatively influences the intracellular Ca2+ transient by changing the affinity of troponin-C for Ca2+. Thus, the interpretation of the measured Ca2+ transients is not simple and the numerous factors involved must be considered. Further study is necessary to elucidate the molecular mechanisms which are responsible for the feedback from the Downstream mechanism to the Central and Upstream mechanisms.