1. Division of Cardiovascular Medicine, Department of Medicine, University of Cambridge, Box 110, Addenbrooke's Centre for Clinical Investigation, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK;
2. INSERM, UMR-1048, Institute of Metabolic and Cardiovascular Diseases and University Paul Sabatier, F-31342 Toulouse, France;
3. Laboratory of Physiopharmacology, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium