ANISOTROPY OF ELECTROTONUS IN THE SINOATRIAL NODE OF THE RABBIT HEART
ANISOTROPY OF ELECTROTONUS IN THE SINOATRIAL NODE OF THE RABBIT HEART
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DOI：
10.1016/0022-2828(89)90651-2
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发表时间：
1989-04-01
影响因子：
5
通讯作者：
JONGSMA, HJ
中科院分区：
文献类型：
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作者：
BOUMAN, LN;DUIVENVOORDEN, JJ;JONGSMA, HJ
在离体兔右心房的窦房结纤维中，在两个方向上测量由细胞内电流注入引起的电势衰减：平行于终嵴和垂直于终嵴。每四个心动周期在舒张期的固定时刻，使用 K+ 灌注的细胞外抽吸电极向位于 SA 结主要中心的纤维施加电流脉冲（10-5 A，60 ms）。电子传播的衰减是通过从电流源沿直线进行的一系列刺穿来测量的。通过将单指数曲线拟合到数据来计算空间常数。在任一方向上都发现空间常数值存在相当大的区域差异。平行于终嵴的平均值为 529 .+-。 446 .mu.m（S.D.，n = 7），垂直于 306 .+-。 295μm（n = 12）；差异不显着（P<0.2）。然而，当从节点的小区域进行测量时，发现电紧张传播存在显着的各向异性（P < 0.05）。在节点的中心观察到电紧张电位在200μm范围内的大的突变。这些数据表明 SA 节点这部分的电紧张分布不均匀。
In fibers of the sinoatrial node of isolated right atria of rabbits the decay of the electrotonic potential caused by intracellular current injection was measured in two directions: parallel to the crista terminalis and perpendicular to it. A K+-perfused extracellular suction electrode was used to apply current pulses (10-5 A, 60 ms) to fibers located in the primary center of the SA node every fourth cardiac cycle at a fixed moment during diastole. The decay of the electronic spread was measured in a series of impalements on a straight line from the current source. Space constants were calculated by fitting single exponential curves to the data. Considerable regional differences in space constant values were found in either direction. Parallel to the crista terminalis the mean value was 529 .+-. 446 .mu.m (S.D., n = 7), perpendicular to it 306 .+-. 295 .mu.m (n = 12); the difference was not significant (P < 0.2). However, a significant anisitropy (P < 0.05) of the electrotonic spread was found when measurements were taken from small areas of the node. Large abrupt changes in the electrotonic potential within 200 .mu.m were observed in the center of the node. These data indicate a non-uniformity of electrotonic spread in this part of the SA node.