1. Department of Chemistry Research and Discovery, ‡Department of Pharmacokinetics and Drug Metabolism, and §Department of Neuroscience, Amgen Inc., 360 Binney Street, Cambridge, Massachusetts 02142, United States
2. Department of Lead Discovery, and ⊥Department of Neuroscience, Amgen, Inc., One Amgen Center Drive, Thousand Oaks, California 91320, United States