1. Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse─Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
2. Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen’s Medical Centre, University of Nottingham, Nottingham NG7 2UH, United Kingdom
3. Centre of Membrane Protein and Receptors, Universities of Birmingham and Nottingham, Midlands NG2 7AG, United Kingdom