1. Laboratory of Clinical Science (O.A.T., D.L.M.), Bethesda, Maryland 20892
2. Section on Pharmacology (I.A., J.M.S.), National Institute of Mental Health, Bethesda, Maryland 20892
3. Clinical Neurocardiology Section, National Institute of Neurological Disorders and Stroke (D.S.G.), National Institutes of Health, Bethesda, Maryland 20892