Key result
Altering extracellular potassium concentration from 2.0 to 16.0 mM in canine cardiac Purkinje fibers did not change intracellular K+ activity (130.0+/-2.3 mM), while K+ equilibrium potential changed.
Population
Beating canine cardiac Purkinje fibers
Comparison
Varying extracellular potassium concentrations vs Tyrode's solution with 4.0 mM potassium…
Design
Preclinical
Authors
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Hypothesis-generating for cardiac K+ homeostasis; leaves open translation from canine Purkinje fibers to human electrophysiology.
Intracellular potassium activity in canine Purkinje fibers remains constant despite changes in extracellular potassium concentration, validating previous indirect estimates.
Miura et al. (1977) studied Beating canine cardiac Purkinje fibers. Extracellular potassium concentration changes vs. 4.0 mM was evaluated on Intracellular K+ activity and transmembrane potentials. Altering extracellular potassium concentration from 2.0 to 16.0 mM in canine cardiac Purkinje fibers did not change intracellular K+ activity (130.0+/-2.3 mM), while K+ equilibrium potential changed.
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