THE PORCINE MU-OPIOID RECEPTOR - MOLECULAR-CLONING AND MESSENGER-RNA DISTRIBUTION IN LYMPHOID-TISSUES

The porcine IJ, opioid receptor (pMOR), was cloned from cerebral corte x RNA using PCR methodologies. Porcine MOR is 96% identical with human MOR in amino acid sequence. An RT-PCR survey for pMOR mRNA indicated that pMOR is widely distributed in the gut, and is present in thymus a nd Peyer's patches but absent in other immune tissues and in isolated immune cells. Based on these findings, it appears that opioids do not exert an immunosuppressive effect through direct interaction with the mu-opioid receptor on immune cells. In certain tissues, however, opioi ds may modulate immune function indirectly through neuronal MOR. (C) 1 998 Elsevier Science B.V. All rights reserved.