Molecular cloning of a novel G protein-coupled receptor that may belong to the neuropeptide receptor family.

A novel cDNA encoding a putative G protein-coupled receptor was isolated from a rat forebrain cDNA library by homology screening. Sequence comparison demonstrates that the encoded polypeptide containing seven transmembrane domains shows highest homology with tachykinin receptors, particularly in the transmembrane domains and the first intracellular loop. The mRNA for this new receptor seems specifically expressed in brain and is prominently localized in specific nuclei of the rat brain, including thalamus, cerebral cortex and hippocampus. We speculate that a neuropeptide may be the natural ligand of this novel G protein-coupled receptor.