INCORPORATION OF 14C FROM [U‐14C]GLUCOSE INTO FREE AMINO ACIDS IN MOUSE BRAIN REGIONS UNDER CYANIDE INTOXICATION

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Abstract
—During anoxia induced by the administration of potassium cyanide, [U‐14C]glucose was injected intraperitoneally into adult mice and they were decapitated at 5, 15 and 30 min after the injection. After freeze‐drying in vacuo, differences in the uptake of radioactive carbon from [U‐14C]glucose into free amino acids (glutamate + glutamine, aspartate + asparagine, GABA, alanine and glycine) in mouse cerebral neocortex, cerebellar hemisphere, caudate nucleus, thalamus, hypothalamus and medulla oblongata were investigated (by macroautoradiography and GLC separation) and compared with those obtained under normal conditions.(1) During anoxia, autoradiographical densities in the thalamus and medulla oblongata were higher than that in the cerebral neocortex and caudate nucleus.(2) Among specific radioactivities (d.p.m./μmol) of free amino acids, alanine gave the highest value during anoxia, except in the cerebellar hemisphere and hypothalamus at 5 min and the medulla oblongata at 30 min.(3) During anoxia, the specific radioactivities of alanine and glycine in each brain region did not significantly decrease at 15 and 30 min compared with those under normal conditions. During anoxia, the specific radioactivity of glutamate + glutamine in the cerebellar hemisphere and hypothalamus did not significantly decrease compared with the normal conditions, while that of GABA, aspartate + asparagine and glutamate + glutamine in the cerebral neocortex, caudate nucleus, thalamus and medulla oblongata showed an increase.(4) The percentage decrease of glutamate + glutamine and aspartate + asparagine at 5 and 15 min was highly significant in the cerebral neocortex and caudate nucleus.