Embryological development of pacemaker hierarchy and membrane currents related to the function of the adult sinus node: implications for autonomic modulation of biopacemakers
Embryological development of pacemaker hierarchy and membrane currents related to the function of the adult sinus node: implications for autonomic modulation of biopacemakers
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DOI：
10.1007/s11517-006-0138-x
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发表时间：
2007-02-01
影响因子：
3.2
通讯作者：
Opthof, Tobias
中科院分区：
文献类型：
--
作者：
Opthof, Tobias
窦结是一个不均匀的结构。在胚胎心脏中，所有肌细胞的肌膜上都有窦结型起搏器通道（I (f)）。出生前不久，这些通道从心室肌细胞中消失。成人窦结对间质变化的反应，特别是对（神经）递质的反应，是其所有组成细胞之间反应的相互作用的结果。整个窦结的反应不能简单地从这些细胞反应中推断出来，因为所有细胞对特定的激动剂有不同的反应。生物起搏器将更加同质化。因此，可以预见，周期长度的调整可能是有问题的。本文讨论了创造对迷走神经刺激有反应的生物起搏器的努力可能会适得其反，因为它可能有生物起搏器“停滞”的潜在风险。正常窦结在高浓度乙酰胆碱下仍保持自发活性，因为窦结有对乙酰胆碱无反应的区域。这同样适用于其他具有负变时作用的物质。这种功能上的不均匀性在生物起搏器中是缺乏的。
The sinus node is an inhomogeneous structure. In the embryonic heart all myocytes have sinus node type pacemaker channels (I (f)) in their sarcolemma. Shortly before birth, these channels disappear from the ventricular myocytes. The response of the adult sinus node to changes in the interstitium, in particular to (neuro)transmitters, results from the interplay between the responses of all of its constituent cells. The response of the whole sinus node cannot be simply deduced from these cellular responses, because all cells have different responses to specific agonists. A biological pacemaker will be more homogeneous. Therefore it can be anticipated that tuning of cycle length may be problematic. It is discussed that efforts to create a biological pacemaker responsive to vagal stimulation, may be counterproductive, because it may have the potential risk of 'standstill' of the biological pacemaker. A normal sinus node remains spontaneously active at high concentrations of acetylcholine, because it has areas that are unresponsive to acetylcholine. The same is pertinent to other substances with a negative chronotropic effect. Such functional inhomogeneity is lacking in biological pacemakers.