1. Laboratory of Medicinal Chemistry, Building 8, Room B1-23, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 8 Center Drive MSC 0815, Bethesda, Maryland 20892, Clinical Psychopharmacology Section, IRP, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland 21224, and Department of Pharmacology and Therapeutics, LSUMC-Shreveport, 1501 Kings Highway, P.O. Box 33932, Shreveport, Louisiana 71130