Non-specific staining of μ-opioid receptors in DRG neurons.

<p>(A) Representative double immunofluorescence images showing similar μ-receptor and PGP 9.5 staining in DRG neurons of wild type mice (left panel) and μ/δ/κ-opioid receptor knockout mice (right panel). Omission of antibodies to μ-receptors and PGP 9.5 resulted in no staining in both genotypes (bottom panel). (B) Representative DAB staining images showing similar μ-receptor labeling in DRG neurons of wild type mice (left image in the upper panel) and μ/δ/κ-opioid receptor knockout mice (right image in the upper panel). In the absence of μ-receptor antibody, some background DAB staining was visible in both genotypes (lower panel). Scale bars = 50 µm.