Primary astrocytes are a type of glial cell found in the central nervous system (CNS) that play important roles in brain function and homeostasis. They are called “primary” astrocytes because they are derived directly from brain tissue, as opposed to being derived from a cell line or a tumor.

Astrocytes are star-shaped cells that provide structural support to the nervous system and regulate the extracellular environment of the brain. They help maintain the balance of ions, neurotransmitters, and other chemicals in the brain, and also play a role in the formation and maintenance of the blood-brain barrier.

In addition to their supportive and regulatory functions, astrocytes also have important roles in neuronal communication and plasticity. They can release chemical messengers, called gliotransmitters, that modulate synaptic activity and contribute to learning and memory processes.

Primary astrocytes are commonly used in neuroscience research as a model system to study the physiology and pathology of the CNS. They can be isolated from brain tissue and grown in culture, allowing for detailed studies of their functions and interactions with other cells in the brain.

Overall, primary astrocytes are essential cells in the CNS that contribute to brain homeostasis and function, and are an important research tool for understanding brain physiology and disease.