Effect of Chronic Dietary Potassium Depletion and Repletion on Cardiac and Skeletal Muscle Structure, Electrolytes and pH in the Rabbit

Abstract

1. Chronic dietary potassium depletion which was severe enough to decrease skeletal muscle intracellular potassium concentration by 20%, did not significantly reduce cardiac intracellular potassium concentration of rabbits. 2. Chronic potassium depletion caused a fall in intracellular pH in skeletal muscle, but no changes occurred in cardiac intracellular pH. 3. Intracellular potassium was increased above normal after 1 week of potassium repletion, but had returned to normal after 3 weeks of repletion. This may have resulted from potassium retaining mechanisms which had developed during depletion and which persisted during the early stages of repletion. 4. Cardiac and skeletal muscle from potassium-depleted animals did not show any structural damage when examined by light and electron microscopy.

Tissue Electrolytes in the Rabbit Following Chronic Dietary Potassium Depletion

“…Chronic K+ depletion in rabbits results in a loss of skeletal muscle K+, with an associated rise in tissue Na+ (Hall & Cameron, 1981). In the heart there are no such changes, and this has been ascribed to an adaptive increase in Na+ pump density (Ward & Cameron, 1984).…”

Subcellular elemental composition in isolated cardiac myocytes from rabbit following chronic potassium depletion and acute repletion, studied by X‐ray microanalysis

“…In the heart this protection has been ascribed to adaptive changes in Na+ pump density (Ward & Cameron, 1984). However cardiac muscle exhibits a defect in contractile performance under these conditions (Ward, 1990), without any apparent morphological change (Hall & Cameron, 1981). Although total tissue electrolytes may not change following K depletion, nothing is known of their relative distribution within the cell.…”