Examination of the metabolism of oedematous brain tissue

Abstract

Oedema were induced in rabbit brains by the application of cold metal to defined areas of intact dura for constant times. Trephine openings were made over the right cerebral hemispheres. 24 hours later the animals were killed, and identical pieces of occipital cortex from both hemispheres were removed. In all specimens we determined the water content, the wager uptake of the sliced brain in vitro, and the glucose metabolism of the brain slices. Respiration, carbon dioxide production in the presence of bicarbonate, consumption of glucose, and production of lactate and pyruvate were measured. The incubations were made in physiological saline (with K +, Ca 2+, Mg 2+ and PO43 additions) in the presence of gas mixtures with different contents of oxygen.The mean difference of the water eonten~s in vivo was 1.3%. The lowest water content after in vitro incubations was found in the presence of 95% 02 and 5% CO2.The oedematous tissue had a slightly stimulated respiration, and its aerobic glycolysis was markedly increased. These metabolic differences were observed only in the presence of 12% 02 and 5% CO~ and higher oxygen concentrations. In the presence of 4% 02 and 5% CO2 neither respiratory nor glyeolytie differences existed between normal and oedematous tissue.A pronounced Pasteur effect was seen in all the experiments. Increase in glycolysis is a more sensitive indicator of oxygen lack than is decrease in respiration.During 150 rain of incubation respiration and carbon dioxide production become slower. The decrease in total and glyeolytie COs production is