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