1.7 expression at caspr-identified nodal sites as related to state of myelination. A-C. Confocal micrographs of collapsed z-projection images (five z-sections with spacing increments of one μm) showing Nav1.7 (red), caspr (green) and myelin basic protein (MBP; blue) staining relationships in one normal (A) and two painful (B and C) samples. A and B. The normal sample (A) shows the expression of MBP and caspr associated with some myelinated fibers (arrows), while this expression is absent in other smaller fibers that most likely lack myelin (arrowheads). The expression of Nav1.7 is prominent within the fibers that lack myelin. In contrast, the painful sample seen in (B) contains many fibers with prominent Nav1.7 expression at caspr-associated nodal sites (white arrows), but that show either alterations (arrowheads) or a lack of MBP staining altogether (black arrows). C. Combined and single channel images of Nav1.7, caspr, and MBP staining relationships seen in a painful sample showing the increased expression of Nav1.7 within an axon segment that is flanked on both sides with caspr and that lacks MBP (arrows), whereas Nav1.7 expression is less in the areas of this same axon where MBP expression is present (arrowheads). Scale bars = 20 μm.