Study of functional coupling among membrane excitation, contraction and mitochondria in cardiac myocyte.

心肌细胞膜兴奋、收缩与线粒体功能耦合研究。

基本信息

批准号：
17590186
负责人：
MATSUOKA Satoshi
金额：
$ 2.3万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

项目摘要

We measured Ca^<2+> of mitochondria matrix in rat ventricular myocytes, which were permeabilized with saponin after loading of Rhod-2AM. Superfusion with a bath solution containing 300 nM Ca^<2+ >and 0 mM Na+ increased the Rhod-2 intensity. The increase was completely abolished by ruthenium red, an inhibitor of Ca^<2+> uniporter, supporting that the Ca^<2+> uiniporter is the main Ca^<2+> influx pathway of mitochondria. Changing the bath solution to that containing 0 Ca^<2+> and 6 mM Na^+ induced a decay of Rhod-2 signal, while only a slight decay was observed without Na^+. Therefore, the Na^+/Ca^<2+> exchange (mNCX) is the main Ca^<2+> efflux mechanism of cardiac mitochondria. The dependence of mNCX on mitochondrial membrane potential (ΔΨ) has been controversial. We measured ΔΨ using TMRE during the same experimental protocol as above inducing Ca^<2+> efflux via mNCX. However, nosignificant change in TMRE fluorescence was observed. To further study the ΔΨ dependence, the Ca^<2+> efflux rate was measured under the condition that the mitochondrial membrane was depolarized by NS 1619 ( an opener of BK channel), FCCP (H^+ ionophore) or removal of mitochondrial substrates (pyruvate, succinate and malate). The Ca^<2+> efflux rate was similar to that measured in the control condition. The above experimental data indicate that Ca^<2+> efflux through mNCX is almost independent of ΔΨ.Based on the above experimental date, we reconstructed a computer model of mitochondria Ca^<2+> dynamics, which consists of Ca^<2+> uniporter, mNCX and a putative Ca^<2+> buffer, and incorporated it into a comprehensive model of cardiac excitation-contraction coupling (Kyoto model). The model analysis indicated that the NADH change, which is dependent on beating frequency, is caused by the increases of ADP and inorganic phosphate (products of ATP hydrolysis) and Ca^<2+> activation of mitochondrial dehydrogenases.

我们测量了大鼠心肌细胞中线粒体基质的Ca^<2+>，在Rhod-2am加载后用皂苷透化。用含有300 nm Ca^<2+>和0 mm Na+的浴溶液的超级灌注增加了Rhod-2强度。 Ca^<2+> Uniporter的抑制剂Ruthenium Red完全消除了增加，支持Ca^<2+> uiniporter是线粒体的主要Ca^<2+>涌入途径。将浴溶液更改为包含0个Ca^<2+>和6 mm Na^+的浴溶液诱导了Rhod-2信号的衰减，而只观察到没有Na^+的轻微衰变。因此，Na^+/Ca^<2+>交换（MNCX）是心脏线粒体的主要Ca^<2+>外排机理。 MNCX对线粒体膜电位（Δψ）的依赖性一直存在争议。我们在与上述诱导的Ca^<2+>外排在相同的实验方案中使用TMRE测量Δψ。然而，观察到TMRE荧光的功能显着变化。为了进一步研究Δψ的依赖性，在线粒体膜通过NS 1619（BK通道的开瓶器），FCCP（H^+离子载体）或去除线粒体（H^+离子载体）或去除线粒体的底物（pyruvate，Sustminate，sust syst，syst sust and Malate和Malate）的情况下，测量了Ca^<2+>外排速率。 Ca^<2+>外排率与在对照条件下测得的相似。 The above experimental data indicates that Ca^<2+> efflux through mNCX is almost independent of ΔΨ.Based on the above experimental date, we reconstructed a computer model of mitochondria Ca^<2+> dynamics, which consists of Ca^<2+> uniaporter, mNCX and a putative Ca^<2+> buffer, and incorporated it into a comprehensive model of cardiac excitement-contraction coupling （京都模型）。模型分析表明，NADH变化取决于跳动频率，是由ADP和无机磷酸盐（ATP水解产物）和Ca^<2+>激活线粒体脱氢酶的激活引起的。

项目成果

期刊论文数量（44）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

simBio : A Java package for the development of detailed cell models.

simBio：用于开发详细细胞模型的 Java 包。

DOI：
发表时间：
2006
期刊：
Progress in Biophysics and Molecular Biology. 90・1-3
影响因子：
0
作者：
Sarai N;Matsuoka S;Noma A.
通讯作者：
Noma A.

Simulation analysis of intracellular Na^+ and Cl-homeostasis during B1-adrenergic stimulation of cardiac myocyte.

B1-肾上腺素能刺激心肌细胞期间细胞内Na+和Cl-稳态的模拟分析。

DOI：
发表时间：
期刊：
Progress in Biophysics and Molecular Biology. (in press)
影响因子：
0
作者：
Masanori Kuzumoto;Ayako Takeuchi;Hiroyuki Nakai;Chiaki Oka;Akinori Noma;Satoshi Matsuoka.
通讯作者：
Satoshi Matsuoka.

Simulation analysis of intracellular Na^+ and C1^- homeostasis during β1-adrenergic stimulation of cardiac myocyte.

β1肾上腺素刺激心肌细胞时细胞内Na^+和C1^-稳态的模拟分析。