Introducing the brain: energy requirements (Introduction)

by David Turell , Tuesday, September 01, 2020, 19:06 (1542 days ago) @ David Turell

Supplying oxygen when needed:

https://www.sciencedaily.com/releases/2020/09/200901085247.htm

"When the brain isn't getting enough oxygen, estrogen produced by neurons in both males and females hyperactivates another brain cell type called astrocytes to step up their usual support and protect brain function.

"In the face of low brain oxygen that can occur with stroke or other brain injury, these astrocytes, star-shaped brain cells that help give the brain its shape and regularly provide fuel and other support to neurons, should become "highly reactive," increasing cell signaling, releasing neuroprotective factors and clearing neurotoxins, scientists report in The Journal of Neuroscience.

"Astrocytes also should start producing protective estrogen, but it's neurons' producing estrogen that is critical to the protective cascade, they report.

"'Astrocytes are always there and hovering and supporting," says Dr. Darrell W. Brann,

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"They found that one way estrogen made by neurons is protective in ischemia is by suppressing signaling of the fibroblast growth factor, FGF2, which is also made by neurons and known to suppress astrocyte activation, Brann and his colleagues write. Normally neurons use this FGF2 brake to help keep astrocyte response from getting out of control.

"In this scenario, when they used a neutralizing antibody to block FGF2, astrocytes became more active and neuron damage was decreased. "The astrocyte activation came back and we saw the protective growth factors that they make," Brann says. Giving more estrogen produced similar benefits, including improving cognition after ischemia.

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"When all is going well in the brain, only neurons appear to be a local estrogen source, but with a stressor like ischemia, aromatase and the estrogen it enables are known to increase significantly in the astrocytes as well, if they are activated."

Comment: More evidence of protective systems in the brain. Should be considered part of the initial design.