Table 1.

Neuropeptide and receptor expression in dorsal root ganglia and trigeminal ganglia

	Dorsal root ganglion			Trigeminal ganglion
Gene symbol and gene name	Mouse TRPV1 lineage RPKM	Mouse non-TRPV1 lineage RPKM	Rat whole ganglion RPKM	Mouse whole ganglion RPKM	Rat whole ganglion RPKM	Human whole ganglion RPKM
Grp, gastrin-releasing peptide	-	-	-	-	-	0.1
Grpr, gastrin releasing peptide receptor	0.2	0.2	-	0.3 ± 0	0.1 ± 0	0.1
Nmb, neuromedin B	170.3	73.7	32.6 ± 4.49	16.5 ± 0.9	13.0 ± 0.3	7.5
Nmbr, neuromedin B receptor	0.1	0.1	0.2 ± 0.02	0.1 ± 0	0.3 ± 0	0.2
Nppa, natriuretic peptide A; ANF	1.5	1.2	5.1 ± 0.73	1.0 ± 0.1	0.8 ± 0.1	1.8
Nppb, natriuretic peptide B; BNP	24.1	0.2	0.7 ± 0.14	2.0 ± 0.1	-	0.8
Nppc, natriuretic peptide C; CNP	-	0.1	-	0.1 ± 0	0.1 ± 0	0.4
Npr1, natriuretic peptide receptor 1; Npra	0.7	1.2	0.8 ± 0.06	1.2 ± 0	0.9 ± 0	0.9
Npr2, natriuretic peptide receptor 2; Nprb	38.1	30	31.7 ± 0.85	35.4 ± 0.4	36.7 ± 0.8	15.3
Npr3, natriuretic peptide receptor 3; Nprc	0.1	0.8	4.1 ± 0.44	2.6 ± 0.1	4.3 ± 0.5	0.3
Tac1, protachykinin-1	597.7	14.1	140.3 ± 10.92	59.8 ± 2.84	122.2 ± 4.9	44.1

The values in the table are average expression levels (and where applicable ± SEM) in RPKM of itch related neuropeptides and their receptors. RPKM is an acronym for Reads Per Kilobase of exon model per Million mapped reads, a normalization which takes into consideration the length of coding exons of genes and depth of sequencing [9]. The mouse DRG dataset consists of TRPV1 lineage and non-TRPV1 lineage RNA samples which were obtained from BAC-TRPV1 promoter-Cre mice as described (Mishra et al., 2011) [6]. Annotation builds mm10, rn4, and hg19 were used, respectively, for the mouse, rat and human genome mapping. Dashes (-) represent values of 20 reads or below; this number of reads is too inaccurate for further consideration.