1. From the San Diego State Heart Institute (G.A.B., M.M., P.Q., M.V., C.C., M.M., S.D., K.F., N.G., D.A., S.B., R.A., S.T., R.W., M.S.G., A.B.G., C.C.G., R.A.G., M.A.S.), San Diego State University, Calif; Department of Pharmacology (S.M., J.H.B.), University of California, San Diego.