Glucose metabolism in the brain

The human brain represents only 2% of the body weight but it utilizes around 20% of total body glucose. This shows how crucial glucose metabolism is for the proper functioning of neurons and other cell types in the brain. Classically, glucose has been viewed mainly as an important fuel source for energy intensive process of neuronal activity. But a closer analysis shows that glucose metabolism in the brain is not so simple and may have many other regulatory functions than just as an energy source. Various cell types of the brain express different specific glucose transporters, which enable them to regulate their glucose metabolism in a very individualized manner. This raises the possibility that glucose metabolism in the brain may have other important physiological relevance as well in specific cell types with different physiology. Considering these broader possibilities, researchers are interested in understanding the regulatory involvement of glucose metabolism in other vital functions of the brain such as redox balance, neuronal plasticity, long-term potentiation, and learning and memory. Of further interest is to understand the metabolic sensing of genes involved in neuronal plasticity. As a part of developing a translational understanding of brain glucose metabolism, research is also focused towards exploring the adaptive and maladaptive consequences of defects in glucose metabolism in Alzheimer’s disease which is seen years before we see any other visible symptoms such as tangles/plaques deposition and memory deficits, etc., in AD patients. It will enable us to find out the key therapeutics targeting specific arms of this pathway, which could not only increase neuroprotection but also enhance neuronal plasticity. Classically, lactate was considered a fuel source only under anaerobic conditions. But many recent findings have established that lactate serves as an important fuel source for neurons even under aerobic conditions. In the light of recent scientific findings, the regulatory role of lactate in the brain seems to be much broader than just an energy source. Researchers are deeply interested in understanding the regulatory involvement of lactate in certain vital functions of neurons other than energy production.