Excitability cycle of cardiac muscle examined by intracellular stimulation.
Excitability cycle of cardiac muscle examined by intracellular stimulation.
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通过细胞内刺激检查心肌的兴奋性周期。
DOI：
10.2170/jjphysiol.12.433
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发表时间：
1962
期刊：
影响因子：
--
通讯作者：
K. Matsuda
中科院分区：
文献类型：
--
作者：
R. Hoshi;K. Matsuda
1.采用细胞内刺激和记录膜电位的方法，研究犬脑室浦肯野终末纤维兴奋性的恢复。阴极刺激的强度-间期曲线呈均匀双曲线，拐点陡峭。它们的变化过程与膜的复极密切相关，其相对不应期对应于复极化的-60~-80 mV.3的时相。刺激阴阳极的强度-间期曲线呈倒尖峰状，早于阴阳极刺激的绝对不应期结束时约15~20ms，在舒张期，完整的纤维对任何阴阳极刺激均无反应。在第二相和第三相的前半部分，阳极电流的断开产生了孤立的尖峰反应，但该反应并不传导。在稍晚的阶段，阳极刺激产生了由尖峰和慢电位组成的反应。在这种情况下，反应是进行的。根据单个纤维的兴奋性曲线，得出结论：在舒张期刺激细胞外阳极激发的兴奋可能是由于阳极周围电流的虚拟阴极效应，而细胞外阴极强度-间隔曲线中观察到的“凹陷”或某些不规则现象在很大程度上可归因于刺激阴极的虚拟阳极效应。这项工作的部分费用由教育部拨款支付。
1. Recovery of the excitability of the terminal Purkinje fibers of the dog ventricle was studied by means of intracellular stimulation and recording of membrane potential.2. The strength-interval curve for the cathodal stimulation was a uniform hyperboloid with a sharp inflection. Their course was closely related to the membrane repolarization, and the relative refractory period corresponded to the phase of repolarization from-60 to-80mV.3. The strength-interval curve for anodal stimulation had a shape of an inverted spike located about 15 to 20 mSec.earlier than the end of the absolute refractory period to the cathodal stimulation.The intact fibers were unresponsive to any anodal stimulation during the diastolic phase.4. Break of anodal current produced an isolated spike response during phase 2 and in the first half of phase 3, but the response did not conduct. At a somewhat later stage, the anodal stimulation produced a response consisting of a spike and slow potential. In this case the response was conductive.5. In view of the excitability curve of a single fiber, it is concluded that the excitation elicited by the extracellular anodal stimulation in the diastolic phase may be due to the virtually cathodal effect of the current around the anode, and the ‘dip’ or some of the irregularities observed in the extracellular cathodal strength-interval curves may largely be ascribable to the virtually anodal effect of the stimulating cathode.The expenses for this work were defrayed, in part, by a grant from the Ministry of Education.