Characterization of Brn3a-positive neurons in the spinal dorsal horn by co-immunostaining with several markers. Brn3a immunostaining together with Pax2 immunostaining, preprodynorphin (Pdyn), cholecystokinin (CCK) or somatostatin (SST) in situ hybridization was performed on transverse sections of the lumbosacral spinal dorsal horn of wild-type mice. (A,D,G,J) Low magnification images of Brn3a immunostaining (magenta) on the left spinal dorsal horn are shown. White dotted lines indicate the boundary between white and gray matters. (B,C) High magnification views (marked in A) of Brn3a signal with (C) or without (B) Pax2 signal (green) around the spinal dorsal horn are shown. (E,F) High magnification views (marked in D) of Brn3a signal with (F) or without (E) Pdyn signal (green) around the spinal dorsal horn are shown. (H,I) High magnification views (marked in G) of Brn3a signal with (I) or without (H) CCK signal (green) around the spinal dorsal horn are shown. (K,L) High magnification views (marked in J) of Brn3a signal with (L) or without (K) SST signal (green) around the spinal dorsal horn are shown. Closed arrowheads indicate cells with positive for Brn3a and markers, whereas open arrowhead indicates Brn3a-single-positive cell. Scale, 100 µm.