1. From the Wolfson Institute for Biomedical Research (R.S.S., M.M., S.M., A.J.H.), University College London, London, United Kingdom; Clinical Pharmacology (S.C., A.A.), William Harvey Research Institute, London, United Kingdom; and the Institute of Physiology and Biophysics (J.A., H.N.), University of Aarhus, The Water and Salt Research Center, Aarhus, Denmark.