Concentration or exclusion of some heterocyclic compounds by brain cortex, in relation to their effects on carbohydrate metabolism

Abstract

Slices of. guinea pig brain cortex shaken aerobically in glucose saline absorbed a number of phenazine and quinoline derivatives (initially at 10-7 to 10-4[image]) until their concns. in the slices were 50-300 times those in the solns. Phenosafranine, diazine green, neutral red, and ethyl red were studied. Nicotine, and nicotinamide, initially at 10-3 to 8 x 10-2 [image], were largely excluded from the slices. Absorption from solns., with 20-30 mg. moist weight of slice/ml., took place gradually over a period of about an hr., and at a max. rate of about 1 [mu]mol./g. moist wt./hr. The absorption was greater aerobically with glucose than anaerobically without glucose; continued metabolism of glucose was necessary for the phenazine and quinoline derivatives to be held in the tissue to their max. extent. The substances named above have the common property of increasing aerobic glycolysis in brain cortex slices, when present in concns. which have little or no effect on respiration. The course of their action on aerobic glycolysis was followed. The concns. of substances in the slices were used as the basis for comparing the actions of the substances on carbohydrate and on cozymase metabolism.