Activity-induced potassium accumulation and its uptake in frog ventricular muscle

The Journal of Physiology
G Martin, M Morad

Abstract

1. Extracellular K+ activity in frog ventricular muscle was monitored with a K+-selective micro-electrode during and following periods of rapid stimulation. 2. During activity K+ accumulated in the paracellular space, declined with continued beating and became depleted below bathing K+ concentrations, [K+], when activity was terminated. 3. The re-uptake and depletion of K+ was inhibited by ouabain, Li+ and lowering bathing [K+], and was enhanced by prolonged stimulation, raising bathing [K+], and by addition of adrenaline. These ionic and drug dependencies of the K+ re-uptake process are similar to the ionic and drug dependencies of the Na+-K+-ATPase system. 4. Frequency-induced K+ accumulation appears to result from a delay in the activation of the Na+ pump. 5. Possible changes in intracellular sodium concentration, [Na+]i, in the response to changes in frequency, appear to be a more powerful stimulant of the K+ re-uptake process than changes in extracellular potassium concentration, [K+]o. 6. Frequency-induced changes in [K+]o were also detected by measurements of resting potential. Alterations in membrane potential and action potential duration observed during and following electrical stimulation are suggestive of an electro...Continue Reading

Citations

Jan 1, 1995·European Journal of Applied Physiology and Occupational Physiology·E Marcos, J Ribas
May 7, 1988·Journal of Theoretical Biology·M R Boyett, D Fedida
Jul 1, 1984·Clinics in Endocrinology and Metabolism·P A Poole-Wilson
Jun 1, 1987·Journal of the American College of Cardiology·S C WebbP A Poole-Wilson
Oct 1, 1983·Journal of Molecular and Cellular Cardiology·G A Langer
Mar 30, 2017·Canadian Journal of Physiology and Pharmacology·M Morad, Xiao-Hua Zhang
Jul 1, 2017·The Journal of Organic Chemistry·H M Dhammika BandaraWilliam R Kobertz
Jun 16, 2018·History and Philosophy of the Life Sciences·Alessio Plebe
Jun 1, 1986·British Heart Journal·S C Webb, P A Poole-Wilson

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