Fig. 2. Quantitative changes in expression of μ-opioid receptor (μOR), green fluorescent protein (GFP), and overlapping μOR immunoreactivity (-ir) with GFP in dorsal hind paw skin at 4 weeks after topical hind paw infection with herpes simplex virus encoding the gene for the μOR in antisense (SGAMOR) or sense (SGMOR) direction relative to the cytomegalovirus promoter, or the viral control encoding β-galactosidase (SGZ). Compared with control SGZ infection, infection with SGAMOR decreases the number of μOR-ir afferent terminals in the epidermis of the medial dorsal hind paw skin. In contrast, infection with SGMOR increases the number of μOR-ir afferent terminals in the epidermis of the medial dorsal hind paw skin. The number of μOR-ir terminals, GFP-positive terminals, and overlap of μOR-ir and GFP were counted in 4-mm sections of skin. Data are presented as average ± SD. *,***  P < 0.05, 0.001 compared with SGZ (one-way analysis of variance followed by  post hoc Bonferroni).