Astrocyte

What is an astrocyte?

An astrocyte is a glial cell in the central nervous system (CNS), which includes the brain and spinal cord. Astrocytes interact with neurons and blood vessels and help maintain the chemical conditions in which neural signaling occurs.

What do astrocytes do?

Sofroniew and Vinters’ review describes their roles in regulating extracellular ions, taking up neurotransmitters such as glutamate, and supporting neural metabolism. Astrocytes also store glycogen, which can contribute fuel under demanding conditions.

Astrocyte processes contact blood vessels and help regulate their properties. The vessel-lining endothelial cells and their tight junctions form the main physical blood–brain barrier. Astrocytes help regulate the vessels; they do not build the barrier alone.

Keeping signals in balance

Taking up glutamate helps clear it after release, while regulating extracellular potassium helps maintain conditions for neuronal signaling. Excessive accumulation can disrupt those conditions. Astrocytes contribute to this regulation alongside other cells and mechanisms.

During development

Astrocytes also release molecular signals that support the formation and function of developing synapses—the connections through which neurons communicate. Their role includes helping establish neural connections as well as supporting existing ones.

In health and injury

Astrocytes differ across brain regions and conditions. Their responses to injury can have protective or harmful effects. Understanding their role in a disease means examining those responses in the affected tissue, alongside what other cells are doing.