(A) qPCR analysis from colonic biopsies from healthy human subjects show low levels of mRNA expression for Tgr5 and absent MrgprX1 (human ortholog of the mouse Mrgpra3 and Mrgprc11) compared with a known epithelial target gucy2c (GC-C, ****P < 0.0001, N = 15 subjects. Dots represent averaged values from each patient sample). (B) qPCR expression analysis of whole human thoracolumbar (TL; T9-L1) DRG from 4 human donors. Analysis reveals abundant expression of MrgprX1, Trpv1, and Trpa1, plus expression of the bile acid receptor Tgr5. Dots represent averaged values from each donor at each DRG level. (C) Single-cell RT-PCR analysis showing the percentage of individual human DRG neurons expressing the Tgr5, MrgprX1, Trpv1, and Trpa1. Data show that, of the 85 individual human thoracolumbar DRG neurons examined, 38% express Tgr5, 79% express MrgprX1, 92% expressed Trpv1, with 58% expressing Trpa1. (D) Donut plot analysis showing coexpression profiles of 85 individual human TL DRG neurons using single-cell RT-PCR for Tgr5, MrgprX1, Trpv1, and Trpa1. (E) Of the 38% of human TL DRG neurons expressing Tgr5, 78% coexpress MrgprX1, 97% coexpress Trpv1, with 56% coexpressing Trpa1. (F) Of the 79% of human DRG neurons expressing MrgprX1, 37% coexpress Tgr5, 99% coexpress Trpv1, with 60% coexpressing Trpa1. (G) Trpv1-expressing human DRG neurons also express Tgr5 (40%), MrgprX1 (85%), and Trpa1 (62%). (H) Trpa1-expressing human DRG neurons also express Tgr5 (31%), MrgprX1 (82%), and Trpv1 (98%). Data in A and B represent mean ± SEM. P values determined by 1-way ANOVA with Tukey’s multiple comparison tests (A).