New York, June 9 (IANS): Star-shaped brain cells appear to help keep blood pressure and blood flow inside the brain on a healthy tone, scientists report.

The finger-like appendages of astrocytes, called end-feet, quite literally wrap around the countless, fragile blood vessels in the brain, constantly monitoring what is going on inside and around them.

"This is the first evidence of the astrocytes' role in pressure-induced myogenic (muscle) tone, which is keeping things regular," said Dr Jessica A Filosa, neurovascular physiologist at Georgia Regents University.

Filosa calls astrocytes "housekeepers". When they sense a change in blood pressure inside the brain, one of their duties is releasing signals that help dilate or constrict the blood vessels, whichever it takes to maintain the healthy status quo.

In fact, astrocytes keep their fingers on the pulse of blood vessels and neurons simultaneously, apparently playing an important role in balancing their needs.

"They are perfect bridges between what is going on with neuronal activity and blood flow changes to the brain."

Astrocytes relentlessly monitor and respond to changes in blood pressure to help keep the brain from getting too much blood.

The team is now looking into what effect activating astrocytes has on neuronal activity.

The paper appeared in The Journal of Neuroscience.