Two levels of resting potential in cardiac Purkinje fibers.
Two levels of resting potential in cardiac Purkinje fibers.
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DOI：
10.1085/jgp.70.6.725
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发表时间：
1977-12
期刊：
影响因子：
--
通讯作者：
Cranefield PF
中科院分区：
文献类型：
--
作者：
Gadsby DC;Cranefield PF
在适当的离子环境中，犬心脏浦肯野纤维的静息电位可能有两个值之一。通过小幅度地改变外加钾浓度[K]（0），结果表明，在本研究所用的低（1 mM）Cl，Na溶液中，只有在[K]（0）值的窄范围内才能获得两个水平的静息电位;在临界[K]（0）范围内，通过施加小电流脉冲，静息电位可以从一个水平移动到另一个水平。结果表明，在这些条件下，稳态电流-电压关系是“N形”，并且负斜率和负弦电导的区域位于两个稳定的零电流电位之间。负弦电导主要是由于内向钠电流，其中只有一部分对河豚毒素（TTX）敏感。在适当的条件下，几种实验性干预措施都能消除负弦电导，使膜电位从静息时的较低水平向静息时的较高水平移动，其中可能通过减少稳态内向电流而有效的干预措施包括降低钠离子浓度、加入TTX或加入利多卡因;可能增加稳态外向电流的因素包括[K]（0）的小幅增加、短暂去极化至约-20 mV或加入氯化乙酰胆碱。
In an appropriate ionic environment, the resting potential of canine cardiac purkinje fibers may have either of two value. By changing the external K concentration, [K](0), in small steps, it was shown that, in the low (1 mM) Cl, Na-containing solutions used in this study, the two levels of resting potential could be obtained only within a narrow range of [K](0) values; that range was usually found between 1 and 4 mM. Within the critical [K](0) range the resting potential could be shifted from either level to the other by the application of small current pulses. It was shown that under these conditions the steady-state current- voltage relationship was “N-shaped,” and that a region of both negative slope, and negative chord conductance lay between the two stable zero-current potentials. The negative chord conductance was largely due to inward sodium current, only part of which was sensitive to tetrodotoxin (TTX). Under appropriate conditions, the negative chord conductance could be abolished by several experimental interventions and the membrane potential thereby shifted from the lower to the higher resting level: those interventions which were effective by presumably diminishing the steady-state inward current included reducing the external sodium concentration, adding TTX, or adding lidocaine; those which presumably increased the steady-state outward current included small increases in [K](0), brief depolarizations to around -20 mV, or the addition of acetylcholine chloride.
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DOI：
10.1085/jgp.67.6.621
发表时间：
1976-06
期刊：
The Journal of general physiology
影响因子：
--
作者：
Hagiwara S;Miyazaki S;Rosenthal NP
通讯作者：
Rosenthal NP
DOI：
10.1085/jgp.27.1.37
发表时间：
1943-09-20
期刊：
The Journal of general physiology
影响因子：
--
作者：
Goldman DE
通讯作者：
Goldman DE
影响因子：
5.5
作者：
AKIYAMA, T;GRUNDFEST, H
通讯作者：
GRUNDFEST, H
DOI：
10.1007/bf00362653
发表时间：
1966-01-01
期刊：
PFLUGERS ARCHIV FUR DIE GESAMTE PHYSIOLOGIE DES MENSCHEN UND DER TIERE
影响因子：
--
作者：
HAAS, HG;KERN, R
通讯作者：
KERN, R
影响因子：
5.5
作者：
HODGKIN, AL;KATZ, B
通讯作者：
KATZ, B