Brain Consumes More Oxygen than Rest of Body

The brain requires more energy in the form of oxygen relative to rest of the body and reacts very sensitively to oxygen deficiency, states a new study published in BMC Biology. Ludwig-Maximilians-Universitaet (LMU) in Munich neurobiologists have now succeeded for the first time in directly correlating oxygen consumption with the activity of certain nerve cells.

The human mind requires biologically an exceptionally large amount of energy in the form of oxygen and glucose contrasted with its weight and size. This energy is for the largely produced by vigorous aerobic metabolic procedures requires significant amount of oxygen. Yet, the oxygen requirements in the brain significantly impacts the functionality of certain nerve cells and glial cells. Nonetheless, how much oxygen is devoured in the brain and how is this correlated with neural activity was so far to a great extent obscure. LMU neurobiologists Hans Straka, Suzan Özugur and Lars Kunz have now succeeded in proving this for the first time in the intact brain, the exact measurements of oxygen and its relationship with neural activity.

The nerve related communication in brain, both voluntary and involuntary activities, as well as neuronal circuits, their signal transmission, and associated housekeeping are energetically demanding. The oxidative phosphorylation, a process for energy production – powerhouse of the body’s system, is most efficient metabolic process that provides large amounts of energy equivalents. It considerably depends on the oxygen consumption. Therefore, oxygen levels in the brain are a critical parameter that influences neuronal function and measurement of oxygen consumption by brain have been used to estimate the cost of neuronal activity; yet, exploring these metabolic relationships in the human body and under defined experimental conditions has been limited by technical challenges.

In the study, the model used to measure oxygen levels is an already established animal model, tadpoles of the clawed frog Xenopus laevis. The research team used an electrochemical sensor to determine the oxygen concentration in the brain and in one of the brain ventricles. They controlled the oxygen amount in the brain and inhibited nerve cell activity with the help of pharmacological substances.

The scientist however were succeeded with the help of using an example of nerve cells that control eye movements, the scientists succeeded in directly recording the relationship between oxygen consumption and nerve cell activity.

“We have found that the brain is anoxic in a normal air-saturated environment, which means that no oxygen can be measured,” says Straka.

He further explained, “We were also able to show that during normal operation only about 50 percent of the oxygen is used for nerve cell activity. So, the other 50 percent are required for glial cells and for maintaining the basic metabolic rate of nerve cells. However, nerve cells with increased activity consume more oxygen.”

To have a clear image of information processing in brain, knowledge of the relationship between oxygen availability and brain activity is essential. The study’s outcomes give integral insight into this and are a significant reason for additional examinations of the rain’s energy balance in future tests and for estimating oxygen consumption by different nerve cells.

Source: Healthy Living Daily

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