1.7 expression in pulp horn. A-F. Confocal micrographs of single optical images showing Nav1.7 (red) expression within N52 (green) and PGP9.5 (blue)-identified nerve fibers within the pulp horn of one normal (A, B) and two painful (C-F) samples. A and B. Nav1.7 (arrow) is expressed in many nerve fibers in the normal pulp horn (A) that stain with N52 and PGP9.5 as seen in the combined image in B. C and D. The pulp horn from a painful sample also shows Nav1.7 expression (arrow) in most nerve fibers that stain with N52 and PGP9.5 as seen in the combined image in D. E and F. The pulp horn of one painful sample contains no Nav1.7 staining (E) within fibers that appear fragmented as visualized with N52 staining (F; arrows). Scale bars = 50 μm.