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. 1984 Nov;46(5):663–668. doi: 10.1016/S0006-3495(84)84065-5

Extracellular [K+] fluctuations in voltage-clamped canine cardiac Purkinje fibers.

R P Kline, I S Cohen
PMCID: PMC1435061  PMID: 6498279

Abstract

Membrane currents and extracellular [K+] were measured in canine Purkinje strands during voltage-clamp steps to plateau or diastolic potentials. Extracellular [K+] increased during step depolarizations and decreased during step hyperpolarizations. On hyperpolarization, the largest fraction of the K+ depletion occurred during the initial 500 ms of the voltage-clamp step and was correlated with a potassium depletion current, the id. A slower component of the depletion also occurred on hyperpolarization and had a time constant consistent with cylindrical diffusion of potassium within the Purkinje strands. On depolarization, there is an accumulation of K+ that is correlated with the plateau current ix. On termination of depolarizing test pulses, the K+ accumulation decays with a time course similar to the ix tail current. Surprisingly, no accumulation of K+ occurred during the arrhythmogenic transient inward current, TI, suggesting that the selectivity of this current should be reevaluated.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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