Quantitative RT/PCR of mRNA was used to estimate the relative expression levels of NR1 in different tissues from 4 Cre+ Prph-fNR1 mice compared to 4 WT (Cre−) littermates. RNA was extracted from DRG (T12-S2), spinal cord, cortex, ileum and colon and amplified with primers specific for NR1 and three housekeeping genes. The 2−ΔCt values in Cre− mice, which reflect NR1 expression levels relative to the housekeeping genes, were 1.15, 0.208, 0.127, 0.00150, 0.000785 for cortex, spinal cord, DRG, colon and ileum, respectively. Expression levels are graphed as the 2−ΔΔCT values which normalizes expression in each tissue from Cre+ mice to that of the same tissue from Cre− mice. * t6 = 2.925, P = 0.0265 Cre+ vs. Cre− mice, unpaired t-test.