- Novel potent and selective central 5-HT3 receptor ligands provided with different intrinsic efficacy. 1. Mapping the central 5-HT3 receptor binding site by arylpiperazine derivatives. Cappelli, A., Anzini, M., Vomero, S., Mennuni, L., Makovec, F., Doucet, E., Hamon, M., Bruni, G., Romeo, M.R., Menziani, M.C., De Benedetti, P.G., Langer, T. J. Med. Chem. (1998)