Energy on demand

Brain displays intrinsic mechanisms to regulate the use of its main energy substrate, i.e. glucose, in register with local variations of functional activity. Despite wide acceptance of this concept, the cellular and molecular mechanisms that underlie this close relationship between neuronal activity and energy metabolism have remained largely unknown. Camillo Golgi suggested more than a hundred years ago that in view of their cytological characteristics, astrocytes could play a central role in the distribution of energy substrates from the circulation to neurons. A series of experiments conducted over the last decade both in vitro and in vivo have shed light on the prominent role played by astrocytes in the regulation of energy metabolism and have revealed the intrinsic mechanism subserving this important function. These results not only provide an insight on how neuronal energy requirements are satisfied upon activation but they could be also relevant for functional brain imaging techniques which rely on such metabolic signals to map cognitive functions. Moreover, the mechanism to locally provide “energy on demand“ to neurons could be part of a larger regulatory system to control the allocation of energy resources between the brain and peripheral organs.

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