1. Department of Medicine and Therapeutics, Western Infirmary, University of Glasgow, G11 6NT Glasgow, United Kingdom;
2. Laboratory of Experimental Hypertension, Clinical Research Institute of Montreal, University of Montreal, Montreal, Quebec, Canada H2W 1R7;
3. Department of Physiology and Endocrinology, Medical College of Georgia, Augusta, Georgia 30912; and
4. Department of Medicine, Boston University, Boston, Massachusetts 02118