LouAnn is being treated for a neurological condition with a specific drug that target neurons deep within the brain. Which glial cell must be bypassed by this drug in order for it to be effective?

A) Astrocyte
B) Microglia
C) Oligodendrocyte
D) Ependymal cell
E) Macrophage

Astrocytes are a type of glial cell that contribute to the blood-brain barrier, a selective barrier that prevents most substances in the blood from entering the brain. For a drug to reach neurons deep within the brain, it must be able to bypass or be transported across this barrier, which involves interaction with astrocytes.