1. School of Pharmacy, Centre for Biomolecular Sciences, University Park Nottingham, Nottingham NG7 2RD, U.K.
2. Division of Physiology, Pharmacology & Neuroscience, Medical School, University of Nottingham, Nottingham NG7 2UH, U.K.
3. Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, the Midlands NG7 2UH, U.K.
4. Medicinal Chemistry, Respiratory, Inflammation and Autoimmunity, IMED Biotech Unit, AstraZeneca, Mölndal, Gothenburg 431 83, Sweden