The present invention relates to a nicotinic acetylcholine receptor subunit alpha polypeptide comprising a polypeptide motif of the sequence of Pro-Ser-Xaa1-Xaa2-Xaa3-Trp (SEQ ID NO:19), wherein Xaa1 refers to Ser, Thr, Ala or Cys； Xaa2 refers to any amino acid moiety； and Xaa3 refers to Ile or Val. Moreover, the invention also relates to a polynucleotide, a cell and an animal comprising such nicotinic acetylcholine receptor subunit alpha polypeptide. The invention further relates to the use of the aforementioned and to methods for determining the effect of the polypeptide according to the present invention.
