[Paracellular ion transfer in kidney and tissues and its pharmacological regulation]

The paper deals with the basic mechanisms underlying the channel reabsorption of sodium and chlorine. The process involves two mechanisms: active transcellular transport of ions and intercellular transport of ions and H2O. Intercellular ion transport directly requires no energy expenditure; nevertheless, it ensures selective ion transport to a certain degree. The hypothesis of fixed entry charges of intercellular compounds (the mechanism which is involved in the treatment of primary urine when the latter passes along the renal tubules) is discussed. Evidence for the existence of this mechanism is given.