EFFECTS OF LOW [K+]O ON THE ELECTRICAL-ACTIVITY OF HUMAN CARDIAC VENTRICULAR AND PURKINJE-CELLS
EFFECTS OF LOW [K+]O ON THE ELECTRICAL-ACTIVITY OF HUMAN CARDIAC VENTRICULAR AND PURKINJE-CELLS
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DOI：
10.1093/cvr/17.4.243
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发表时间：
1983-01-01
影响因子：
10.8
通讯作者：
CHRISTE, G
中科院分区：
文献类型：
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作者：
CHRISTE, G
在人乳头肌条上用微电极记录心室和浦肯野动作电位。将灌流溶液的K含量从5.9降至0.5 mmol. l-1，37 °。C超极化心室舒张电位稳定，只要[K+]o低（长达70分钟测试）。心室动作电位短暂延长，然后缩短。注意到正性肌力作用，并归因于Na-K泵抑制，因为它被加入2 mmol. cnt. l ~（-1）氯化亚铊对低[K ~+]O溶液的稳定性。在低[K+]o的最初几分钟内，浦肯野舒张期电位超极化，复极各水平的动作电位均延长。之后，浦肯野舒张电位突然去极化30 mV。对照溶液的恢复引起缓慢的复极，然后舒张电位突然恢复到接近对照值。这在驱动期间再现（38 stim. cntdot. min-1）和静止时。在去极化电位水平，刺激诱发慢动作电位，慢去极化，静息时出现自发电位振荡。在浦肯野细胞中，将河豚毒素的浓度从10-7增加到8。10-6摩尔数L ~（-1）使舒张期电位负移数mV，使复极各水平动作电位时程缩短。这些现象在一些心律失常的成因可能产生的影响进行了讨论。
Ventricular and Purkinje action potentials were recorded with a microelectrode in a strip of human papillary muscle. Lowering the K-content of the superfusing solution from 5.9 to 0.5 mmol .cntdot. l-1 at 37.degree. C hyperpolarized ventricular diastolic potential steadily as long as [K+]o was low (up to 70 min tested). Ventricular action potentials were transiently lengthened and then shortened. A positive inotropic effect was noted and attributed to Na-K pump inhibition since it was reversed by the addition of 2 mmol .cntdot. l-1 thallous chloride to the low [K+]o solution. Beyond 40 min, transient depolarizations and after-contractions were found. During the first minutes in low [K+]o, Purkinje diastolic potential was hyperpolarized and the action potential was lengthened at all levels of repolarization. Afterwards, the Purkinje diastolic potential suddenly depolarized by 30 mV. Restoration of the control solution caused a slow repolarization and then a sudden return of the diastolic potential to near control value. This was reproduced during drive (38 stim .cntdot. min-1) and at rest. At the depolarized level of potential, stimulation elicited slow action potentials with slow depolarization and spontaneous oscillations of potential appeared at rest. In Purkinje cells, increasing concentrations of tetrodotoxin from 10-7 to 8 .RTM. 10-6 mol .cntdot. l-1 in the control solution shifted the diastolic potential in negative direction by a few mV and shortened the action potential duration at all levels of repolarization. The possible implications of these phenomena in the genesis of some cardiac arrhythmias is discussed.