Electrically active axons in white matter stimulate their own myelination by releasing glutamate, which signals through AMPA-type glutamate receptors on nearby oligodendrocyte precursors and newly-differentiating oligodendrocytes, enhancing their survival and hence their ability to myelinate.
Oligodendrocytes in white matter use Kir4.1 inwardly rectifying potassium channels to prevent extracellular potassium accumulation, enabling neurons to sustain repetitive firing and limiting the initiation of seizures.
In oligodendrocyte progenitor cells, lipid metabolism and peroxisome biogenesis are regulated by the low-density lipoprotein related-receptor-1, and if disrupted, impair proper white matter development and adult repair.
Ultrastructural and loss-of-function experiments show that oligodendrocyte-encoded Kir4.1 is located near active axonal structures, including within myelin inner tongue, and has critical functions to promote axonal activity and preserve integrity.
The signaling lipid PI(3,5)P2 supports the formation of the myelin sheath, by regulating trafficking of myelin building blocks within oligodendrocytes and communication between oligodendrocytes and neuronal axons.