Effect of Replacement of Potassium by Rubidium on the Transmembrane Action Potential and Contractility of Human Papillary Muscle

doi:10.1161/01.RES.24.2.157

Paper

Effect of Replacement of Potassium by Rubidium on the Transmembrane Action Potential and Contractility of Human Papillary Muscle

Published Feb 1, 1969 · K. Prasad, J. Callaghan

Circulation Research

Q1 SJR score

34

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1

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Abstract

The effects of extracellular rubidium chloride (1, 2, 4, and 8 mM) on simultaneously recorded transmembrane action potentials and contractions of human papillary muscle in potassium-free solutions were investigated. In KCl-free solution, reduction in the duration of the action potential at the 25% and 50% levels of repolarization was associated with an increase in the force of contraction. Exposure of the muscle to rubidium chloride led to an increase in the duration of the action potential at 25% and 50% levels of repolarization associated with a corresponding decrease in the force of contraction. A decrease in the force of contraction was more usually associated with an increase in the duration of the action potential at the 25% level of repolarization than at the 50% level. No appreciable change in the duration of the action potential at the 90% level of repolarization was observed. Increases in the duration associated with corresponding decreases in the force of contraction were concentrationdependent. Rubidium chloride (8 mM) produced a conduction delay and inexcitability in the muscle. It has been suggested that in KCl-free solution the reduction in the duration of the action potential and an increase in the force of contraction were associated with inhibition of membrane ATPase. Also, the increases in the duration of the action potential accompanied by decreases in the force of contraction were associated with rubidium chloride-induced stimulation of membrane ATPase in human myocardium.

In Vitro Study

Study Snapshot

Rubidium chloride increases the duration of action potentials in human papillary muscle, resulting in a decrease in force of contraction, with concentration-dependent effects.

PopulationOlder adults (50-71 years)

Sample size24

MethodsObservational

OutcomesBody Mass Index projections

ResultsSocial networks mitigate obesity in older groups.

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Paper

Effect of Replacement of Potassium by Rubidium on the Transmembrane Action Potential and Contractility of Human Papillary Muscle

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References

An Electrophysiologic Correlate of Ouabain Inotropy in Canine Cardiac Muscle

Ouabain inotropy in canine cardiac muscle is correlated with phase 2 abbreviation of action potentials, indicating that both interval-dependent contractile potentiation and ouabain inotropy involve phase 2 abbreviation.

Potassium in Dog Ventricular Muscle: Kinetic Studies of Distribution and Effects of Varying Frequency of Contraction and Potassium Concentration of Perfusate

Increased frequency of contraction in dog ventricular muscle leads to a transient net loss of intracellular potassium, which may influence myocardial contractility control.

ENZYMATIC BASIS FOR ACTIVE TRANSPORT OF NA+ AND K+ ACROSS CELL MEMBRANE.

The enzyme system plays a crucial role in active transport of Na+ and K+ across the cell membrane, with its activation affecting cation transport and ATP production.

Ouabain Effects on Cardiac Contraction, Action Potential, and Cellular Potassium

Ouabain at low concentrations decreases intracellular potassium levels in myocardial cells, suggesting a close relationship between potassium loss and inotropic effect, but action potentials do not consistently change.

Potassium and rubidium exchange across the surface membrane of cardiac purkinje fibres

Rubidium can largely replace potassium in cardiac tissue, but their permeabilities to potassium and rubidium are not equal, and muscle cells tend to accumulate rubidium in preference to potassium.

Citations