title: AT-1001 Is a Partial Agonist with High Affinity and Selectivity at Human and Rat α3β4 Nicotinic Cholinergic Receptors.
abstract: AT-1001 [N-(2-bromophenyl)-9-methyl-9-azabicyclo[3.3.1] nonan-3-amine] is a high-affinity and highly selective ligand at α3β4 nicotinic cholinergic receptors (nAChRs) that was reported to decrease nicotine self-administration in rats. It was initially reported to be an antagonist at rat α3β4 nAChRs heterologously expressed in HEK293 cells. Here we compared AT-1001 actions at rat and human α3β4 and α4β2 nAChRs similarly expressed in HEK 293 cells. We found that, as originally reported, AT-1001 is highly selective for α3β4 receptors over α4β2 receptors, but its binding selectivity is much greater at human than at rat receptors, because of a higher affinity at human than at rat α3β4 nAChRs. Binding studies in human and rat brain and pineal gland confirmed the selectivity of AT-1001 for α3β4 nAChRs and its higher affinity for human compared with rat receptors. In patch-clamp electrophysiology studies, AT-1001 was a potent partial agonist with 65-70% efficacy at both human and rat α3β4 nAChRs. It was also a less potent and weaker (18%) partial agonist at α4β2 nAChRs. Both α3β4 and α4β2 nAChRs are upregulated by exposure of cells to AT-1001 for 3 days. Similarly, AT-1001 desensitized both receptor subtypes in a concentration-dependent manner, but it was 10 and 30 times more potent to desensitize human α3β4 receptors than rat α3β4 and human α4β2 receptors, respectively. After exposure to AT-1001, the time to recovery from desensitization was longest for the human α3β4 nAChR and shortest for the human α4β2 receptor, suggesting that recovery from desensitization is primarily related to the dissociation of the ligand from the receptor.
authors.affiliation: Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.).
authors.forename: Edward W
authors.initials: EW
authors.lastname: Tuan
authors.affiliation: Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.).
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Horti
authors.affiliation: Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.).
authors.forename: Thao T
authors.initials: TT
authors.lastname: Olson
authors.affiliation: Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.).
authors.forename: Yongiun
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.).
authors.forename: Craig A
authors.initials: CA
authors.lastname: Stockmeier
authors.affiliation: Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.).
authors.forename: Nour
authors.initials: N
authors.lastname: Al-Muhtasib
authors.affiliation: Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.).
authors.forename: Carrie
authors.initials: C
authors.lastname: Bowman Dalley
authors.affiliation: Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.).
authors.forename: Amanda E
authors.initials: AE
authors.lastname: Lewin
authors.affiliation: Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.).
authors.forename: Barry B
authors.initials: BB
authors.lastname: Wolfe
authors.affiliation: Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.).
authors.forename: Niaz
authors.initials: N
authors.lastname: Sahibzada
authors.affiliation: Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.).
authors.forename: Yingxian
authors.initials: Y
authors.lastname: Xiao
authors.affiliation: Department of Pharmacology & Physiology, Georgetown University School of Medicine, Washington, DC (E.W.T., T.T.O., N.A.-M., C.B.D., A.E.L., B.B.W., N.S., Y.X., K.J.K.); Department of Radiology Division of Nuclear Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland (A.G.H., Y.G.); and Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, Mississippi (C.A.S.) kellark@georgetown.edu.
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Kellar
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D054333:Drug Partial Agonism; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D008297:Male; D018722:Nicotinic Agonists / Q000378:metabolism* / Q000494:pharmacology; D009842:Oligopeptides / Q000378:metabolism* / Q000494:pharmacology; D011485:Protein Binding / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011978:Receptors, Nicotinic / Q000378:metabolism*; D013045:Species Specificity
chemical_list: D018722:Nicotinic Agonists; D009842:Oligopeptides; D011978:Receptors, Nicotinic; C403530:nicotinic receptor alpha3beta4; C525167:larazotide acetate