OLIGODENDROCYTE
BIOLOGY
Oligodendrocytes are
neuroectodermally derived glial cells that have the major role of myelinating
central axons. The trigger for myelination may include associated axonal size
and signal molecules (such as ATP, K+, glutamate, GABA, and some
cell adhesion molecules).
Each oligodendrocyte can myelinate individual
intermodal segments of an average of 30 separate axons (as high as 60 axons);
adjacent internodal segments are myelinated by different oligodendrocytes. This
pattern of central myelination leaves periodic nodes of Ranvier bare, with
sodium channels, at which action potentials (APs) are reinitiated as they
travel down the myelinated axon and its branches (called saltatory
conduction). Oligodendrocytes can be attacked by antibodies directed at
specific oligodendrocyte proteins in multiple sclerosis, leading to
oligodendrocyte death and axonal dysfunction. Oligodendrocyte precursor cells
can replicate following such insults and remyelinate the denuded central axon
segments. Oligodendrocyte membranes possess monocarboxylate transporter 1 (MCT
1), which can deliver lactate, pyruvate, and ketone bodies to the axon.
Oligodendrocyte precursor cells (OPCs) are present in the adult CNS and have
NG2 and PDGFα