Characteristics of ionic binding by rat renal tissue in vitro.

Abstract

4. In cortical slices in media containing equimolar Cl-and other monovalent anions, binding occurred according to the sequence acetate < salicylate < Cl-< SCN-; Cl-was completely displaced by P043-.5. When medium pH was lowered, Na+ binding was markedly reduced in both regions, whereas C1-binding increased (and became significant in outer medulla).6. In NaCl solutions, Na+ binding capacity was saturated at control Na+ concentrations. When [Na+] was progressively reduced (iso-osmolality being maintained by addition ofurea), bound Na+ in both regions was nearly linearly related to log medium [Na+].7. Raising medium osmolality with urea caused decreased Na+ binding and increased Cl-binding in both regions.8. Na+ binding in both regions was significantly reduced by pre-treatment with chondroitinase ABC.9. Binding of both ions was independent of temperature within the range 2-37°C.10. The possibility is raised that renal ionic binding might influence vectorial ion transport by affecting free ion activity in the region of the transporting cells.

Sodium and Hemodialysis

“…The mucopolysaccharide sodium reservoir will release sodium into the osmotic pool, stimulating thirst and driving extracellular volume expansion. Polyanions are ubiquitously distributed: bone (Woodbury, 1956), cartilage (Dunstone, 1959), blood vessels (Tobain et al, 1961), liver, intestine, brain, kidney (Law, 1984), lung and skin (Titze et al, 2003). Given this distribution, it should not be surprising that extracellular, soluble sodium makes up approximately 75% of total body sodium (Bergstrom, 1955).…”