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: I. Chemical Composition of Various Specific Areas and Structures of the Brain in the Dog and the Monkey

Abstract

A method is described in which a train of chemical analyses can be performed on 0.5- to l.0-gm samples of brain tissues whereby water, total lipid, total nitrogen, chloride, sodium, potassium, and magnesium can be determined in succession. In 19 normal dogs and 2 normal monkeys, the gray matter and caudate nucleus were found to have water (about 80%) ana lipid (4 to 5%) contents quite different from those of the white matter (water 68%, lipid 17%). The sum of water and lipid in these as well as in other tissues (corpus callosum, thalamus, medulla oblongata) was between 83% and 86%. The gray and white matter had the same concentrations of Na (79) and K (125), whereas the caudate nucleus had lower concentrations (Na 68, K 113), all in miluivalents per kilogram of H2O. The chloride space of issues analyzed ranged from 26 to 31% of the fresh weight, or 37 to 42% of the total water. The variance of the values for the chemical constituents determined in different animals was quite small, thus permitting the comparison of these normal data with those obtained under pathological conditions. Most of the variance observed was probably due to true individual variations, sincemore » in the same animals the results obtained on the two sides of the brain showed very good agreement and the water contents of various parts of the brain showed definite correlation.« less