Effect of infusion of rubidium chloride on plasma electrolytes and the electrocardiogram of the dog

¹ Departments of Medicine and Pharmacology, Boston University School of Medicine, and the Evans Memorial Department of Clinical Research and Preventive Medicine, Massachusetts Memorial Hospitals, Boston, Massachusetts

Infusion of rubidium chloride solutions into anesthetized dogs resulted in rapid cellular uptake of most of the rubidium in apparent exchange for intracellular potassium. Plasma concentrations and renal excretion of potassium rose and there was a progressive fall in plasma bicarbonate. The resultant sequence of changes in the electrocardiogram could be best correlated with the increased plasma concentrations of rubidium plus potassium, and in many respects was indistinguishable from the effects produced by equivalent rises in potassium alone. In half the experiments, however, ventricular irritability seemed to be increased by rubidium, suggesting that this ion does have effects of its own which are different from those of potassium. It is suggested that the greater irritative action of rubidium may be due to a depolarizing effect of intracellular rubidium on the cell membrane.