Subpial and perivascular astrocytes associated with nodes of Ranvier in the rat optic nerve

Recent evidence has suggested that there is a division of labour between two types of astrocytes in the rat optic nerve--one type extending processes to the pial surface and to blood vessels, the other extending processes to nodes of Ranvier (Miller et al., 1989b). Here we show that astrocytes and astrocyte processes located at the pial surface and around blood vessels in the rat optic nerve can also be associated with nodes of Ranvier, indicating that the division of labour between the two types of astrocytes in the nerve is not as strict as previously proposed.