GLYCOLYTIC SUBSTRATE UTILIZATION AND ENERGY CONSUMPTION IN THE CEREBRAL HEMISPHERES OF THE CHICK EMBRYO DURING THE PERIOD OF EEG DEVELOPMENT

Abstract— The glycolytic substrate utilization and energy consumption of chick embryo hemispheres aged 15 and 19 days, respectively, were studied by converting the heads into a closed system. After transforming the brain into a closed system by decapitation, spontaneous bio-electrical potential changes, as indicated by EEG measurements, stayed normal in the hemispheres until at least 30 s after the procedure. Although the two developmental stages studied represented the start and the final phase of functional development, no changes in carbohydrate utilization and energy consumption were observed when comparing hemispheres of the two stages mentioned. The utilization of substrates other than glucose during embryological development is discussed. The disappearance of the EEG is not related to the overall depletion of high energy phosphates in the hemispheres since ATP is still present at nearly its original level after 2 min of ischaemia, despite the low level of P-creatine occurring at 30 s after decapitation. A compartmentation of the major pools of P-creatine and ATP is suggested.