Neurons energy requirements

The brain and other areas of the central nervous system (CNS) have high ATP requirements. Although the brain only represents about 2% of the body s mass, it consumes around 20% of the metabolized oxygen and ca. 60% of the glucose. The neurons high energy requirements are mainly due to ATP-de-pendent ion pumps (particularly Na7K " AT-Pase) and other active transport processes that are needed for nerve conduction (see p. 350). 

Energy requirement Neurons require the continuous supply of glucose and oxygen in order to generate the large amount of ATP needed to support various cellular processes... 

The energy requirements of the neuron needed to maintain the Na" " and K+ gradients are pronounced. The maximal rate of ATP hydrolysis under conditions of maximal cation exchange has been estimated to be between 15 and 30% of the total hydrolysis of ATP within the neuron. In comparison, the combination of protein and lipid turnover and biosynthesis of neurotransmitters appears to require only 10% of the total ATP hydrolysis of the nerve. (The remaining hydrolysis occurs during active transport of other substances and for a variety of enzymatic reactions.)... 

Nicotera P, Leist M, Fava E, Berliocchi L, Volbracht C. Energy requirement for caspase activation and neuronal cell death. Brain Pathol. 2000 10 276-282... 

Adenosine triphosphate (ATP) The principal chemical energy source for cellular processes. It is largely produced during aerobic metabolism. In the neuron most ATP is used in the maintenance of the electrochemical gradient required to generate an action potential. 

Neurons oxidize glucose by glycolysis and the citric acid cycle, and the flow of electrons from these oxidations through the respiratory chain provides almost all the ATP used by these cells. Energy is required to create and maintain an electrical potential across the neuronal plasma membrane. The membrane contains an electrogenic ATP-driven antiporter, the Na+K+ ATPase, which simultaneously pumps 2 K+ ions into and 3 Na+ ions out of the neuron (see Fig. 11-37). The resulting... 

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