MOR-1C

 C. E. Groer, K. Tidgewell, R. A. Moyer, W. W. Harding, R. B. Rothman, T. E. Prisinzano, and L. M. Bohn. An Opioid Agonist that Does Not Induce mu-Opioid Receptor---Arrestin Interactions or Receptor Internalization. 0026-895X/07/7102-549–557. MOLECULAR PHARMACOLOGY. 

...Cells were resuspended in Triton X-100 extraction buffer [10 mM Tris, pH 7.5, 120 mM NaCl, 25 mM KCl, 1 mM PMSF, 1 protease inhibitor pellet/10 ml (Roche), 1 mg/ml iodoacetamide, and 0.5% Triton X-100] and solubilized on ice for 2 h. Lysates were cleared by 12,000 rpm spin and then added to avidin-conjugated agarose beads (Pierce) for immunoprecipitation overnight at 4°C with rotation. Immunoprecipitates were centrifuged at 12,000 rpm and washed three times with Triton X-100 extraction buffer and once with PBS plus 0.1% SDS. Immunoprecipitates were washed, and proteins were eluted and resolved as described in the coimmunoprecipitation experiments. Immunoblots were performed using the  mOR C-terminal directed antibody (Neuromics, Edina, MN), donkey anti-rabbit secondary antibody, and enhanced chemiluminescence detection...

D. Blivis, G. Z. Mentis, M. J. O'Donovan and A. Lev-Tov. Differential Effects of Opioids on Sacrocaudal Afferent Pathways and Central Pattern Generators in the Neonatal Rat Spinal Cord.J Neurophysiol 97: 2875-2886, 2007. First published February 7, 2007; doi:10.1152/jn.01313.2006 0022-3077/07.

...MOR-1 (either from Neuromics or Chemicon, raised in rabbit, in a working dilution 1:500)...