Connexin32 gene expression in rat sciatic nerves and cultured Schwann cells

A Western blot analysis showed connexin32 (Cx32) to be present in the myelin membrane. Cx32 mRNA rapidly decreased in the distal segments of crushed sciatic nerves and thereafter returned to normal, as did P0 mRNA. Both Cx32 and P0 mRNAs were detectable in cultured Schwann cells and were enhanced by the addition of forskolin. The developmental profile showed that Cx32 mRNA had thus markedly increased by the time that myelination had become most active, and thereafter only slowly increased unlike P0. Cx32 mRNA seems to parallel myelin size, which thus suggests that Cx32 supports myelin maintenance as a gap junction protein that facilitates the intramyelin exchange of small molecules.