1. From the Departments of Pharmacology and Physiology (H.W., E.A.O., R.T.D., B.C.B., A.V.S.) and Biochemistry and Biophysics (H.W., A.V.S.) and the Cardiovascular Research Institute (N.M., T.A.B., B.C.B.), University of Rochester School of Medicine, Rochester, NY; and Departments of Pharmacology (K.L.V., G.G.K.) and Medicine (G.G.K.), State University of New York Upstate Medical University, Syracuse.