title: Involvement of Nax sodium channel in peripheral nerve regeneration via lactate signaling.
abstract: Na(x), a sodium concentration-sensitive sodium channel, is expressed in non-myelinating Schwann cells of the adult peripheral nervous system, but the pathophysiological role remains unclear. We found that functional recovery of the hind paw responses from the sciatic nerve transection was delayed in Na(x) knockout (Na(x)⁻/⁻) mice. Histological analyses showed a decrease in the number of regenerated myelinated axons in (Na(x)⁻/⁻) sciatic nerves. The delay in the recovery in Na(x)⁻/⁻ mice was improved by lactate and inhibited by a monocarboxylate transporter inhibitor. In vitro experiments using cultured Schwann cells showed that lactate release was enhanced by endothelin (ET)-1 and blocked by an ET receptor type B antagonist. Here, it is conceivable that Na(x) was activated by ET-1. The amount of lactate release by ET-1 was lower in Na(x)⁻/⁻ mice than in wild-type mice. These results indicated that Na(x) is functionally coupled to ET for lactate release via ET receptor type B and is involved in peripheral nerve regeneration.
authors.forename: Sawako
authors.initials: S
authors.lastname: Unezaki
authors.forename: Tayo
authors.initials: T
authors.lastname: Katano
authors.forename: Takeshi Y
authors.initials: TY
authors.lastname: Hiyama
authors.forename: Nguyen H
authors.initials: NH
authors.lastname: Tu
authors.forename: Satoru
authors.initials: S
authors.lastname: Yoshii
authors.forename: Masaharu
authors.initials: M
authors.lastname: Noda
authors.forename: Seiji
authors.initials: S
authors.lastname: Ito
mesh_terms: D000818:Animals; D019771:Axotomy; D002478:Cells, Cultured; D016232:Endothelins / Q000378:metabolism; D007150:Immunohistochemistry; D019344:Lactic Acid / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D046529:Microscopy, Electron, Transmission; D009416:Nerve Regeneration / Q000502:physiology*; D010525:Peripheral Nerves / Q000378:metabolism; D017466:Receptors, Endothelin / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012584:Sciatic Nerve / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D015222:Sodium Channels / Q000378:metabolism*
chemical_list: D016232:Endothelins; D017466:Receptors, Endothelin; D015222:Sodium Channels; D019344:Lactic Acid