1. Serono Pharmaceutical Research Institute, Departments of Chemistry and Biochemical Pharmacology, 14 Chemin des Aulx, 1228 Plan-Les-Ouates, Geneva, Switzerland; Istituto di Ricerche Biomediche “A. Marxer”, Departments of Pharmacology and DMPK, Colleretto Giacosa, Italy; Evotec OAI, Milton Park, Abingdon, Oxon OX14 4SD, U.K; and Institut National de la Santé et de la Recherche Médicale U469, Montpellier, France