09-12-2021-2217 - Astrocytes astroglia cavity star cell

 Astrocytes (from Ancient Greek ἄστρον, ástron, "star" + κύτος, kútos, "cavity", "cell"), also known collectively as astroglia, are characteristic star-shaped glial cellsin the brain and spinal cord. They perform many functions, including biochemical support of endothelial cells that form the blood–brain barrier,^[1] provision of nutrients to the nervous tissue, maintenance of extracellular ion balance, regulation of cerebral blood flow, and a role in the repair and scarring process of the brain and spinal cord following infection and traumatic injuries.^[2] The proportion of astrocytes in the brain is not well defined; depending on the counting technique used, studies have found that the astrocyte proportion varies by region and ranges from 20% to 40% of all glia.^[3] Another study reports that astrocytes are the most numerous cell type in the brain.^[2] Astrocytes are the major source of cholesterol in the central nervous system.^[4] Apolipoprotein E transports cholesterol from astrocytes to neurons and other glial cells, regulating cell signaling in the brain.^[5] Astrocytes in humans are more than twenty times larger than in rodent brains, and make contact with more than ten times the number of synapses.^[6]

Research since the mid-1990s has shown that astrocytes propagate intercellular Ca²⁺ waves over long distances in response to stimulation, and, similar to neurons, release transmitters (called gliotransmitters) in a Ca²⁺-dependent manner.^[7] Data suggest that astrocytes also signal to neurons through Ca²⁺-dependent release of glutamate.^[8] Such discoveries have made astrocytes an important area of research within the field of neuroscience.

An astrocyte from a rat's brain grown in tissue culture and stained with antibodies to GFAP(red) and vimentin (green). Both proteins are present in large amounts in the intermediate filaments of this cell, so the cell appears yellow. The blue material shows DNA visualized with DAPI stain, and reveals the nucleus of the astrocyte and of other cells. Image courtesy of EnCor Biotechnology Inc.

• Circadian clock: Astrocytes alone are sufficient to drive the molecular oscillations in the SCN and circadian behavior in mice, and thus can autonomously initiate and sustain complex mammalian behavior.^[33]

https://en.wikipedia.org/wiki/Astrocyte


https://en.wikipedia.org/wiki/SLIT1
https://en.wikipedia.org/wiki/Reelin
https://en.wikipedia.org/wiki/NKX6-1
https://en.wikipedia.org/wiki/PAX6
https://en.wikipedia.org/wiki/Wnt_signaling_pathway
https://en.wikipedia.org/wiki/Bone_morphogenetic_protein
https://en.wikipedia.org/wiki/Astrocyte