Fig. 4.

The expression of GalR1 and Scratch2 in the vPAG. GalR1 transcript expression in the vPAG detected by RNAscope assay at three different levels of adult rat brain sections. (A) The density of GalR1⁺ cells is highest in the rostral PAG. (Scale bar, 200 µm.) (B) A rostral section of adult rat PAG triple-labeled for GalR1, Slc17a6 (VGLUT2), and Slc32a1 (VGAT) transcripts using multiplexed RNAscope assay. Arrowheads point to GalR1⁺ neurons expressing Slc17a6 (selected region 1: lateral vPAG) and Slc32a1 (selected region 2: medial vPAG), respectively. Note very high density of VGLU2 cells in the dorsal PAG. (Scale bar, 200 µm in main figure, 30 μm in selected regions.) (C) RNAscope image showing expression of Scratch2 in the GalR1⁺/Slc17a6⁺ subgroup in the vPAG. (Scale bar, 20 µm.) (D) RNAscope image showing expression of Scratch2 in the GalR1⁺/Slc32a1⁺ subgroup in the vPAG. (Scale bar, 20 µm.)