Elsevier

The Journal of Pain

Volume 10, Issue 7, July 2009, Pages 750-758
The Journal of Pain

Original Report
Sodium Channel Expression and Localization at Demyelinated Sites in Painful Human Dental Pulp

https://doi.org/10.1016/j.jpain.2009.01.264Get rights and content
Under an Elsevier user license
open archive

Abstract

The expression of sodium channels (NaCh(s)) change after inflammatory and nerve lesions, and this change has been implicated in the generation of pain states. Here we examine NaCh expression within nerve fibers from normal and painful extracted human teeth with special emphasis on their localization within large accumulations, like those seen at nodes of Ranvier. Pulpal tissue sections from normal wisdom teeth and from teeth with large carious lesions associated with severe and spontaneous pain were double-stained with pan-specific NaCh antibody and caspr (paranodal protein used to visualize nodes of Ranvier) antibody, while additional sections were triple-stained with NaCh, caspr and myelin basic protein (MBP) antibodies. Z-series of images were obtained with the confocal microscope and evaluated with NIH ImageJ software to quantify the density and size of NaCh accumulations, and to characterize NaCh localization at caspr-identified typical and atypical nodal sites. Although the results showed variability in the overall density and size of NaCh accumulations in painful samples, a common finding included the remodeling of NaChs at atypical nodal sites. This remodeling of NaChs included prominent NaCh expression within nerve regions that showed a selective loss of MBP staining in a pattern consistent with a demyelinating process.

Perspective

This study identifies the remodeling of NaChs at demyelinated sites within the painful human dental pulp and suggests that the contribution of NaChs to spontaneous pulpal pain generation may be dependant not only on total NaCh density but may also be related to NaCh expression at atypical nodal sites.

Key words

Dental pulp
demyelination
sodium channel
caspr/contactin
nodes of Ranvier
myelin basic protein

Cited by (0)

Supported by NIH Grant DE015576 from the National Institute of Dental and Craniofacial Research.