In the brains of living animals, it is said that a mechanism to maintain energy homeostasis works to prevent the depletion of energy required for all cell activities.It has been expected that this mechanism would keep cell energy levels constant in the brains of living animals, but no studies have proved this.

　This time, the research group measured the intracellular concentration of ATP (adenosine triphosphate), which is a molecule used as energy for cells, from the brain of a living mouse in real time.As a result, the intracellular ATP concentration of the excitatory nerve in the cerebral cortex of the mouse was high during the awakening of the mouse, decreased from the awakening to the non-REM sleep, and further decreased to the REM sleep.On the other hand, the cerebral blood flow, which represents the energy supply to the cells, increased slightly during non-REM sleep and greatly increased during REM sleep as compared with the time of awakening of the mouse.

　In addition, intraneuronal ATP increases throughout the cerebral cortex during awakening, when cellular energy demand increases.It was predicted that there may be a whole-brain level energy regulation mechanism that rapidly increases intracellular ATP in nerve cells over a wide area of ​​the brain from sleep to awakening of animals.

　This study overturns the conventional expectation that "cell energy levels are always kept constant" in the brains of living animals, and that the neuronal energy in the cerebral cortex fluctuates with sleep and arousal in animals. Clarified.In the future, it is expected that the intracellular energy consumption activity and the brain system will be elucidated.

Paper information:[Communications Biology] Intracellular ATP levels in mouse cortical excitatory neurons vary with sleep-wake states