The Journal of comparative neurology
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After spinal cord injury (SCI), white matter tracts are characterized by demyelination and increased sensitivity to the K(+) channel blocker 4-aminopyridine (4-AP). These effects appear to contribute to neurological impairment after SCI, although the molecular changes in K(+) channel subunit expression remain poorly understood. We examined changes in gene expression of the 4-AP-sensitive voltage-gated K(+) channel Kv 1.4 after chronic SCI in the rat. ⋯ Finally, quantitative in situ hybridization showed that Kv 1.4 mRNA was significantly upregulated in spinal cord white matter, but not gray matter, after SCI. In summary, we show that Kv 1.4 is expressed in glial cells and not in axons in the rat spinal cord white matter and that its expression is markedly increased in cells of the oligodendrocyte lineage after chronic SCI. Given that K(+) channels play a role in glial cell proliferation, cells exhibiting changes in Kv 1.4 expression may represent proliferating oligodendroglia in the chronically injured spinal cord.