The present invention provides uses of a polypeptide having a ligand activity to a sensory epithelium neuropeptide-like receptor (SENR) which is a G protein-coupled receptor protein, and a DNA encoding the same. More specifically, the present invention provides an anti-attention-deficit-disorder or anti-narcolepsy agent, which comprises a polypeptide having a ligand activity for SENR or a salt thereof, as well as a method for screening compounds having an anti-attention-deficit-disorder or anti-narcolepsy activity or compounds having an anti-anxiety, anti-depression, anti-insomnia, anti-schizophrenia or anti-fear activity or salts thereof, which comprises using the above polypeptide or a precursor protein of the polypeptide or a salt thereof.
USE OF POLYPEPTIDE