Chimeric gabab receptor

The present invention provides an isolated GABAB receptor protein comprising at least one GABABR1a subunit and at least one GABABR2a subunit, characterized in that said GABAB receptor has one high affinity agonist binding site and one low affinity agonist binding site. In particular the isolated recombinant GABAB receptor protein expressed by the hGABABR1a/GABABR2 CHO cell line deposited at the Belgian Coordinated Collections of Microorganisms (BCCM) as CHO-K1 h-GABA-b R1a/R2 clone on Aug. 22, 2003 with the accession number LMBP 6046CB. It is thus an object of the present invention to provide the hGABABR1a/GABABR2 CHO cell line deposited at the Belgian Coordinated Collections of Microorganisms (BCCM) as CHO-K1 h-GABA-b R1a/R2 clone on Aug. 22, 2003 with the accession number LMBP 6046CB. The invention also provides the use of the aforementioned cell line in a method to identify GABAB receptor agonists using a functional or a binding assay. In particular in a radioligand-binding assay comprising the use of radiolabeled agonists such as for example 3H-GABA or 3H-baclofen. In a particular embodiment the present invention provides the use of the aforementioned GABAB receptor in a method to identify a high affinity GABAB receptor agonist using a functional or a binding assay. In particular in a radioligand-binding assay comprising the use of radiolabeled agonists such as for example 3H-GABA or 3H-baclofen. Alternatively, the aforementioned binding assays are performed on cellular extracts, in particular cellular membrane preparations of the aforementioned cells.