Background:Studies from our laboratory have identified a novel mu opiate receptor, mu3, which is expressed in several tissues, such as human vascular endothelial cells, leukocytes and invertebrate neural tissues. This novel mu receptor has been shown to be selective for opiate alkaloids, insensitive to opioid peptides, and also is coupled to constitutive nitric oxide release.Material/Methods: In this study, we compare the mu3 receptor gene expression from three different vascular endothelial primary cell lines at the molecular level using a Taqman probe for the mu opiate receptor.Results: Results from this study demonstrate that human umbilical vein endothelial cells (2.0, relative gene expression) and human pulmonary artery endothelial cells (1.1, relative gene expression) expressed more of the mu opiate receptor as compared to human arteriole endothelial cells (0.82, relative gene expression).Conclusions: The individual variations in mu receptor expression in these vascular tissues may explain the large variance in graft survival using saphenous veins for coronary artery bypass surgery.

Keywords: Receptors, Opioid, mu - genetics, Base Sequence, Endothelial Cells - metabolism, Molecular Sequence Data, Polymerase Chain Reaction, Receptors, Opioid, mu - genetics, Transcription, Genetic - genetics