A Study on Oxygen Consumption in the Limbic System, Especially in the Hippocampus

The oxygen consumption rate (Qo2) of the limbic system, especially the hippocampus, of adult rats was measured under various conditions which have been applied to treatment of psychosomatic disease. The Qo2 of the brain was lower in female than in male rats. The Qo2 was found to be the highest in the diencephalon, next in the neocortex and the lowest in the limbic system. The hippocampus Qo2 was affected by various conditions, whereas that of the olfactory gyrus was not. The hippocampus Qo2 was raised during estrus, recovery from fasting, after glucose injection in the insulin-treated group and by administration of estrogen; while it was lowered during diestrus and by treatment with progesterone, testosterone and chlorpromazine. With noradrenaline and zinc gluconate the hippocampus Qo2 tended to decrease slightly. However, meprobamate, reserpin, γ-oxybutylic acid, monoamine oxidase inhibitor, change in the blood sugar level and electrical stimulation of the olfactory nerve have no effect. In experimental neurosis the 90 minutes value of the hippocampus Qo2 tended to be lowered.