1. Divisions of Clinical Pharmacology, Department of Medicine (K.E., A.W., S.P., M.S., S.K., A.D., C.A.S., I.B.), Vanderbilt University Medical Center, Nashville, TN.
2. Autonomic Dysfunction Center (K.E., A.W., S.Y.P., A.D., C.A.S., I.B.), Vanderbilt University Medical Center, Nashville, TN.
3. and Vanderbilt Eye Institute (K.M.J.), Vanderbilt University Medical Center, Nashville, TN.