For decades, scientists have suspected that the brain had a way of monitoring and regulating its own blood flow separate from the body-wide blood pressure control system, but until now no one had proven this.
The brain needs more blood than any other organ to satisfy neurons’ relentless, high demand for oxygen, so it makes sense that it would have a way of buffering itself from blood flow fluctuations in the wider body.
Disturbances to brain blood flow are a known cause in many diseases — for example, sustained reduction in brain blood flow is a likely cause of cognitive decline, dementia, and neurodegenerative disease such as Alzheimer’s disease.
In a recent study from UCL, researchers have discovered the mechanism that allows the brain to monitor its own blood supply.
The finding may help find new treatments for high blood pressure and dementia.
The study is published in Nature Communications. The lead author is Professor Alexander Gourine (UCL Division of Biosciences).
In the study, the team found a new function for the star-shaped brain glial cells, known as astrocytes.
These cells function as specialized brain blood flow sensors that operate to self-protect the brain from potentially damaging reductions in blood supply.
Astrocytes are strategically positioned between the brain blood vessels and important nerve cells, which control the heart and peripheral circulation, ultimately determining the arterial blood pressure.
In the laboratory study, the researchers found that decreases in brain blood flow caused astrocytes to release a chemical signal, which stimulated the specialized nerve cells to increase blood pressure and restore/maintain blood flow (and oxygen supply) to the brain.
The team says in disease situations where the blood supply to the brain is reduced, the mechanisms can over-react causing migraines, high blood pressure, and strokes.
The identity of the brain blood flow sensor will make it possible to search for novel targeted treatment strategies to alleviate these diseases.
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