Characterization Tac2-Cre expressing neurons in the dorsal horn of the spinal cord. A: A transverse section through a P30 spinal cord showing fluorescent Tomato expression enriched in dorsal horn neurons as indicated by the large arrow. Small arrow indicates sporadic Tomato-positive neurons in the deep dorsal horn. B: Enlarged inset of the dorsal horn (A), showing Tomato-positive neurons in lamina I (arrowhead), as well as the ventral layer of inner lamina II and lamina III (large arrow). Note the local processes in lamina II/III (small arrow). C: Double staining of Tomato fluorescence (red) and fluorescently conjugated isolection IB4 (green). Tomato-positive neurons are located ventral to the dorsal layer of inner lamina II marked by IB4-positive sensory terminals. D: Transverse section of a P10 spinal cord illustrating a lamina I neuron with long processes. E: Co-localization of Tomato and Tac2 transcripts. Sections were first photographed for Tomato fluorescence (red), then used to conduct in situ hybridization (pseudo-colored green), and the resultant signals were merged. Large arrow indicates a neuron co-expressing Tomato and Tac2 mRNA, while arrowhead indicates one that expressed Tomato but not Tac2 mRNA. Small arrow indicates neuronal processes within inner lamina II and lamina III. F-H: Double staining of Tomato (red) and antibodies (green) against PKCγ (F), Tlx3 (G), and Pax2 (H). Arrows mark double-positive neurons and arrowheads mark Tomato-positive neurons that did not co-express PKCγ (F) or Tlx3 (G).