Time delays in propagation of cardiac action potential.
Time delays in propagation of cardiac action potential.
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心脏动作电位传播的时间延迟。
DOI：
10.1152/ajpheart.1990.258.6.h1906
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
R. Mark
中科院分区：
文献类型：
--
作者：
D. A. Israel;D. Edell;R. Mark
最近的研究表明，在生理条件下，心肌细胞之间可能发生离散的时间延迟。为了研究这种时间延迟的存在，单层的10天鸡胚心室肌细胞生长在细胞培养的细胞外微电极阵列。最紧密间隔的记录电极位于20微米的中心。一些电极对从同一细胞的不同点记录，而另一些电极对跨越细胞间连接。电起搏制备物以获得可重复的繁殖途径。测量每个微电极处的激活到达时间。对照记录后，将制备物暴露于含有20 mM NH4Cl的培养基15 min，然后返回正常培养基。这种干预产生短暂的细胞内酸化，减少细胞间的耦合。酸化后，平均（多细胞）传导速度下降到约三分之二的控制值。在大多数电极对之间测量的传播速度成比例地降低。然而，在各种实验中，在一些电极对之间观察到高达410微秒的不成比例的长传播延迟。随着pH值恢复正常，延迟恢复。局部长时间延迟被认为是由于间隙连接处细胞间耦合减少。
Recent work has suggested that discrete time delays could occur between cardiac cells under physiological conditions. To investigate the existence of such time delays, monolayers of 10-day chick-embryo ventricular myocytes were grown in cell culture on arrays of extracellular microelectrodes. The most closely spaced recording electrodes were on 20-microns centers. Some pairs of electrodes recorded from different points on the same cell, whereas other pairs straddled intercellular junctions. The preparation was electrically paced to obtain a repeatable propagation pathway. Arrival times of activation at each microelectrode were measured. After control recordings, the preparation was exposed to medium containing 20 mM NH4Cl for 15 min and then returned to normal medium. This intervention produces transient intracellular acidification that decreases intercellular coupling. After acidification, the average (multicellular) conduction velocity decreased to about two-thirds of the control value. Propagation velocity measured between most electrode pairs decreased proportionately. However, disproportionately long propagation delays of up to 410 microseconds were observed between some pairs of electrodes in various experiments. The delays recovered as pH returned to normal. The localized long delays were thought to be due to decreased intercellular coupling at gap junctions.