Analysis of the staircase phenomenon of the cardiac muscle contraction under the patch clamp conditions

膜片钳条件下心肌收缩阶梯现象分析

• 批准号: 12470007
• 负责人: NOMA Akinori
• 金额: $ 8.96万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12470007/
• 关键词: cardiac myocyte; contraction; Sarcomere length; staircase; 心筋; Caバッファー; 筋小胞体; 筋節; 心室筋細胞

Under the patch clamp conditions, we recorded changes in the sarcomere pattern by projecting the image of the single ventricular myocyte onto the linear image sensor in parallel to the membrane current recordings. The cycle length of individual sarcomere, when recorded every 2 msec, showed a micro fluctuations even under the holding potential at -40 mV. When the external Ca^<2+> is removed, the fluctuation was largely depressed. Under the Ca^<2+> overload conditions, induced by applying 5.4 mM Ca^<2+> and ouabain, the miniature fluctuations were largely enhanced as revealed by the increase in the power below 10 Hz in the FFT analysis. The application of ryanodine suppressed these fluctuations, leaving the mean sarcomere length relatively short. When the cell contraction was evoked by applying depolarizing pulses, the variation among different sarcomeres within the cell was increased when compared with the resting condition. This was typically observed when the open probability of the L-type Ca^<2+> channels was low at the test pulse to -30 mV. These findings well supported the local control theory of the excitation-contraction coupling.

在膜片钳条件下，我们记录的肌节图案的变化，通过投影到线性图像传感器上的单个心室肌细胞的图像平行于膜电流记录。当每隔2 msec记录时，即使在-40mV的保持电位下，单个肌节的周期长度也显示出微小的波动。当去除外部Ca^<2+>时，波动被大大抑制。在由5.4 mM Ca^2+和哇巴因诱导的Ca^2+过载条件下，微小波动大大增强，如FFT分析中10 Hz以下功率的增加所揭示的。应用ryanodine抑制了这些波动，使平均肌节长度相对较短。当施加去极化脉冲引起细胞收缩时，与静息状态相比，细胞内不同肌节之间的变化增加。当L-型Ca^<2+>通道的开放概率在测试脉冲至-30 mV时较低时，通常会观察到这种情况。这些结果很好地支持了兴奋-收缩耦合的局部控制理论。

项目成果

Satoshi Matsuoka: "Role of individual ionic current systems in ventricular cells hypothesized by a model study"Japanese Journal of Physiology. (印刷中). (2003)

Satoshi Matsuoka：“模型研究捕获的单个离子电流系统在心室细胞中的作用”日本生理学杂志（2003 年）。

Kuratomi S, Matsuoka S, Sarai N, Powell T, Noma A.: "Involvement of Ca^<2+> buffering and Na^+/Ca^<2+> exchange in the positive staircase of contraction in guinea pig ventricular myocytes"(in press). (2003)

Kuratomi S、Matsuoka S、Sarai N、Powell T、Noma A.：“豚鼠心室肌​​细胞收缩正阶梯中 Ca^<2> 缓冲和 Na^/Ca^<2> 交换的参与”（新闻中）

Sarai N, Matsuoka S, Kuratomi S, Ono K, Noma A.: "Role of individual ionic current systems in the SA node hypothesized by a model study"Jpn. J. Physiol.. (in press). (2003)

Sarai N、Matsuoka S、Kuratomi S、Ono K、Noma A.：“通过模型研究假设的 SA 节点中单个离子电流系统的作用”Jpn。

Sarai N, Matsuoka S, Kuratomi S, Ono K, Noma A.: "Role of individual ionic current systems in the SA node hypothesized by a model study"Jpn. J Physiol. in press. (2003)

Sarai N、Matsuoka S、Kuratomi S、Ono K、Noma A.：“通过模型研究假设的 SA 节点中单个离子电流系统的作用”Jpn。

Mitsuiye T: "Sustained Inurerd Current During Pacemaker Depolaigation in Mammalion Sinoatrial Node Cells"Circulation Research. 87. 88-91 (2000)

Mitsuiye T：“哺乳动物窦房结细胞起搏器去极化期间持续的 Inurrd 电流”循环研究。