(A) RT-PCR analyses of NR1 in rat colon (named GI, for gastrointestinal) and brain tissues using two different set of primers; NR1 general and NR1 generic, that recognize areas in the NR1 outside the spliced exons. Assessment of housekeeping gene, GAPDH (Glyceraldehyde-3-phosphate dehydrogenase) was included as a control for sample integrity and reaction fidelity. A negative control (−RT) was included which lacks Reverse transcriptase and uses GAPDH primers. (B) Top panel, western blot showing broad expression of NR1 protein in GI and brain tissues using general mouse-NR1 antibody that recognizes a site outside of the alternatively spliced cassettes. Bottom panel, an antibody against actin was use as a control for loading purposes.