D1R and D5R mRNAs are highly expressed in the lamina III/IV of the dorsal horn of the spinal cord. A, Image showing the pattern of D1R and D5R mRNA expression in the brain. B, D1R mRNA expression is significantly higher in the caudate compared with D5R mRNA, whereas D5R mRNA is predominantly expressed in CA1 where D1R mRNA is almost completely absent. Images are representative of 3 mice. C, Images showing the pattern of expression of the D1R and D5R mRNAs in the spinal cord. D, CTCF analysis demonstrates a significant higher level of D1R and D5R mRNAs in the spinal cord of male compared with female mice. E, Moreover, D1R and D5R are highly enriched in the lamina III/IV of the spinal cord in male and female mice. N = 3 mice per group. *p < 0.05 (t test with correction for multiple comparisons). **p < 0.01 (t test with correction for multiple comparisons).