Figure 4.

Immunocytochemistry of the spinal dorsal horn from Dbh^−/− and control mice. (a, a′) Immunostaining for α_2A receptor. (b, b′) α_2C receptor. NK1 receptor (d, d′) and μ-opioid receptor (e, e′) showed no difference between Dbh^−/− and control mice. (c, c′) Substance P (SP) labeling differed between Dbh^−/− and control mice. There was decreased staining in the Dbh^−/− mice, which was confirmed for the superficial layers of the dorsal horn (black arrowhead) by densitometry (see text). For all antigens, the Dbh^−/− and control tissues were processed at the same time in adjacent wells under the same conditions. (Bar = 300 μm.)