Neuromedin U (NmU) is a peptide which regulates peripheral functions such as smooth muscle contraction and blood pressure, and CNS functions including nociception and feeding activity (Brighton et al., 2004a). Two GPCRs, NMU1 and NMU2, mediate the contractile effects of neuromedin U by activation of both Gq and Gi (Brighton et al., 2004b). Compared to the wide distribution of NMU1 in peripheral tissue, expression of NMU2 receptor is limited to areas of the brain, such as the paraventricular nucleus, along the wall of the third ventricle in the hypothalamus and the CA1 region of the hippocampus, and to the spinal cord (Howard et al. 2000). Recent study has shown that mice deficient in NMU2 but not NMU1 receptor had impaired nociceptive responses suggesting that the pro-nociceptive effects of NmU in mice appear to be mediated through NMU2 (Zeng et al., 2006; Torres et al. 2007). Millipore’s cloned human NMU2-expressing cell line is made in the Chem-1 host, which supports high levels of recombinant NMU2 expression on the cell surface and contains high levels of the promiscuous G protein to couple the receptor to the calcium signaling pathway. Thus, the cell line is an ideal tool for screening for agonists and antagonists at NMU2.