Immunoblotting of MOPRs in mouse brains and 3HA-tagged hMOPRs in CHO cells was carried out according to our published method [27,30]. Protein samples were prepared with 2 × Laemmli sample buffer and loaded (20 μg protein per lane) for SDS-PAGE and Western blot was performed with anti-mu C or an antibody against the HA-tag (HA.11), followed by goat anti-rabbit or anti-mouse IgG conjugated with HRP (1:5,000), respectively, and then reacted with enhanced chemiluminescence (ECL) Western blotting detection reagents. Images were captured with a FujiFilm LAS-1000 Imaging System.
