Nucleic acid molecules encoding a KOR3 kappa opioid receptor and the methods of producing the encoded receptor

An isolated polynucleotide that encodes a mammalian KOR-3 receptor, wherein the polynucleotide comprises the nucleotide base sequence of SEQ ID NO:

• 1.

An expression vector comprising a polynucleotide that encodes a mammalian KOR-3 receptor comprising an amino acid residue sequence of sequence SEQ ID NO:

• 2.

A transformed host cell comprising a polynucleotide that encodes a mammalian KOR-3 receptor polypeptide, wherein the polynucleotide comprises the nucleotide base sequence of SEQ ID NO:

• 1.

A polynucleotide encoding a KOR-3 receptor wherein said polynucleotide is at least 95% homologous to SEQ ID NO:

• 1 and wherein the encoded receptor binds OFQ/nociceptin.

A process for preparing a transformed host cell expressing a mammalian KOR-3 receptor polypeptide comprising the steps of:

• a) transfecting, electroporating or transforming a cell with the KOR-3 receptor-encoding polynucleotide of claim 18, to produce a transformed host cell;
• and
• b) maintaining the transformed host cell under biological conditions sufficient for expression of said mammalian KOR-3 receptor polypeptide in the host cell.

A polynucleotide encoding a KOR-3 receptor wherein said receptor is at least 95% homologous to SEQ ID NO:

• 2 and wherein the encoded receptor binds OFQ/nociceptin.