Sodium channel Nav1.6 accumulates at the site of infraorbital nerve injury.

Sodium channel (NaCh) expressions change following nerve and inflammatory lesions and this change may contribute to the activation of pain pathways. In a previous study we found a dramatic increase in the size and density of NaCh accumulations, and a remodeling of NaChs at intact and altered myelinated sites at a location just proximal to a combined partial axotomy and chromic suture lesion of the rat infraorbital nerve (ION) with the use of an antibody that identifies all NaCh isoforms. Here we evaluate the contribution of the major nodal NaCh isoform, Nav1.6, to this remodeling of NaChs following the same lesion. Sections of the ION from normal and ION lesioned subjects were double-stained with antibodies against Nav1.6 and caspr (contactin-associated protein; a paranodal protein to identify nodes of Ranvier) and then z-series of optically sectioned images were captured with a confocal microscope. ImageJ (NIH) software was used to quantify the average size and density of Nav1.6 accumulations, while additional single fiber analyses measured the axial length of the nodal gap, and the immunofluorescence intensity of Nav1.6 in nodes and of caspr in the paranodal region.

Pubmed ID: 17662136 RIS Download