Why is the brain the largest energy consumer in the body?

The human brain consumes more energy than other organs. This information may surprise many people but it is the truth. But why is the brain the organ that consumes the most energy? The answer is gradually being revealed by scientists through in-depth studies on the human brain.

New research from Weill Cornell Medicine has found this happens even during times when the brain is at rest and neurons aren't communicating as they should to each other.

Even in a state of inactivity, such as a coma, for example, the brain's glucose consumption often drops from normal levels to only about half.

Neurotransmitter encapsulation may be responsible for this energy loss.

Scientists believe that the encapsulation of neurotransmitters (chemical molecules used by the nervous system to transmit messages between nerve cells) may be responsible for the energy expenditure. this.

The experts identified synaptic vesicles that appear to be the main energy consumers of dormant neurons. These vesicles are used as reservoirs for neurotransmitters that are released from the synapse to send signals to other neurons when the brain is active.

According to the scientists, the packing of neurotransmitters into synaptic vesicles is a process that is always leaky and leads to a significant loss of energy even when the vesicles are full and the synaptic terminals are full. Menstrual inactive.

During synaptic shutdown, the vesicles contain thousands of neurotransmitters but show signs of leaking energy or 'proton outflow' from their membranes. So a particular 'proton pump' enzyme needs to stay active and lead to energy consumption.

The energy that sustains the nerve conduction is always leaking

The researchers found that the likely source of this proton leak were proteins called transporters (which normally deliver neurotransmitters into synaptic vesicles) that change shape to carry the transmitter. nerve into the sac but at the same time allowing the proton to escape. The energy source to maintain this shape change is kept low and allows for faster neurotransmitter recharge, allowing for faster thinking and action.

The packing of neurotransmitters into synaptic vesicles is a process that always involves leakage.

The study's author, Timothy Ryan, professor of Biochemistry at Weill explains: 'The downside of faster transmission is that even random thermal fluctuations can trigger a conformational change of the carrier. transfer, causing constant energy expenditure even when no neurotransmitter is moving'.

Although the leakage per vesicle is very small, there are hundreds of trillions of synaptic vesicles in the human brain, so energy expenditure increases dramatically.

The findings not only provide new insight into the brain, but also open avenues for treating metabolic deficiencies in diseases like Alzheimer's or Parkinson's.

Dr Ryan concludes: 'If we had a way to safely reduce this energy expenditure and slow down metabolism in the brain it could have a huge clinical impact. '.

The study was recently published in the journal Science Advances.