1. From the Department of Medical Pharmacology and Physiology (J.A.C.-G., S.D.Z., M.L., L.A.M.-L., M.J.D.), University of Missouri, Columbia
2. Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City (R.S.S.)
3. Department of Physiology, University of Arizona, Tucson (A.M.S.)
4. Institute of Physiology, University of Luebeck, Germany (C.d.W.)
5. Department of Medicine (R.d.l.T.), University of Missouri, Columbia
6. Department of Pharmacology, University of Vermont, Burlington (G.W.H.).