SUGAR AND OXYGEN METABOLISM OF THE BRAIN DURING AND AFTER INSULIN HYPOGLYCEMIA

Abstract

One of the most widely held theories to explain the improvement reported in the psychoses following metrazol and insulin shock therapy is that the respiration of the brain is stimulated. Gerard¹ suggested that the cerebral hypoxia which occurs during the metrazol convulsion or insulin hypoglycemia is followed by a period of "overshooting," i. e., hyperactivity with increased oxygen consumption by the brain, which may depend on liberation of potassium from the interior of the neuron. According to the investigations of Gerard and Magoun,² a moderate increase in external potassium ions acts as a great stimulus to neural activity. Although cerebral hypoxia occurs during the metrazol convulsion³ and insulin hypoglycemia,⁴ there is no adequate evidence that increased respiration of the brain follows the depression of metabolism. Whether the increased electrical activity exhibited by the brain when deprived of oxygen or sugar or when exposed to cyanide or