Department of Medicinal Chemistry, the University of Kansas, Lawrence, Kansas (C.W.C., T.E.P.); and Clinical Psychopharmacology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland (R.B.R.)

Department of Medicinal Chemistry, the University of Kansas, Lawrence, Kansas (C.W.C., T.E.P.); and Clinical Psychopharmacology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland (R.B.R.)

Department of Medicinal Chemistry, the University of Kansas, Lawrence, Kansas (C.W.C., T.E.P.); and Clinical Psychopharmacology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland (R.B.R.)

Department of Medicinal Chemistry, the University of Kansas, Lawrence, Kansas (C.W.C., T.E.P.); and Clinical Psychopharmacology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland (R.B.R.)