The invention relates generally to compositions of and methods for
obtaining mu opioid receptor polypeptides. The invention relates as well
to polynucleotides encoding mu opioid receptor polypeptides, the
recombinant vectors carrying those sequences, the recombinant host cells
including either the sequences or vectors, recombinant opioid receptor
polypeptides, and antibodies immunoreactive with mu opioid receptors. The
invention includes as well, methods for using the isolated, recombinant
receptor polypeptide in assays designed to select and improve substances
capable of interacting with mu opioid receptor polypeptides for use in
diagnostic, drug design and therapeutic applications.