Studies on the Chemical Composition of the Central Nervous System in Relation to the Effects of X-Irradiation and of Disturbances in Water and Salt Balance: III. Effects of Disturbances in Water and Electrolyte Balance on the Chemical Composition of Brain Tissues in Dogs

Abstract

The chemical composition of gray matter, white matter, and caudate nucleus was determined in dogs subjected to various types of disturbances in water and electrolyte balance, and the results were compared with those obtained on normal dogs. Intraperitoneal dialysis resulted in the depletion of Na, K, and Cl and an increase in intracellular hydration (calculated from Cl space). Water loading caused an increase in water content and dilution of electrolytes. After sucrose diuresis, the brain lost more water than electrolytes, and hence the concentration of the latter (in milliequivalents per kilogram of H2O) increased. As a result of the injection of hypertonic NaCl solution, the Na and Cl concentrations increased markedly, whereas the water content decreased. These changes in the brain are qualitatively the same as those occurring elsewhere in the body. Even from a quantitative point of view, the changes in the brain are similar to those found in other tissues. Therefore, the brain is not always specifically guarded against chemical changes, and the methods employed were adequate for the detection of the changes in chemical composition of brain tissues. In the experiments where x irradiation was superimposed on the disturbances in fluid balance, beside the findings attributable tomore » the latter maneuvers, there was an increase in the Na concentration of the caudate nucleus similar to that found in the dogs receiving x irradiation only.« less