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Di Ciano P, Hendershot CS, Le Foll B. Therapeutic Potential of Histamine H3 Receptors in Substance Use Disorders. Curr Top Behav Neurosci 2022; 59:169-191. [PMID: 35704272 DOI: 10.1007/7854_2022_372] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Substance use disorders are a leading cause of morbidity and mortality, and available pharmacological treatments are of modest efficacy. Histamine is a biogenic amine with four types of receptors. The histamine H3 receptor (H3R) is an autoreceptor and also an heteroreceptor. H3Rs are highly expressed in the basal ganglia, hippocampus and cortex, and regulate a number of neurotransmitters including acetylcholine, norepinephrine, GABA and dopamine. Its function and localization suggest that the H3R may be relevant to a number of psychiatric disorders and could represent a potential therapeutic target for substance use disorders. The purpose of the present review is to summarize preclinical studies investigating the effects of H3R agonists and antagonists on animal models of alcohol, nicotine and psychostimulant use. At present, the effects of H3R antagonists such as thioperamide, pitolisant or ciproxifan have been investigated in drug-induced locomotion, conditioned place preference, drug self-administration, reinstatement, sensitization and drug discrimination. For alcohol and nicotine, the effects of H3R ligands on two-bottle choice and memory tasks, respectively, have also been investigated. The results of these studies are inconsistent. For alcohol, H3R antagonists generally decreased the reward-related properties of ethanol, which suggests that H3R antagonists may be effective as a treatment option for alcohol use disorder. However, the effects of H3R antagonists on nicotine and psychostimulant motivation and reward are less clear. H3R antagonists potentiated the abuse-related properties of nicotine, but only a handful of studies have been conducted. For psychostimulants, evidence is mixed and suggests that more research is needed to establish whether H3R antagonists are a viable therapeutic option. The fact that different drugs of abuse have different brain targets may explain the differential effects of H3R ligands.
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Affiliation(s)
- Patricia Di Ciano
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
- Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Christian S Hendershot
- Bowles Center for Alcohol Studies, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Bernard Le Foll
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
- Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, Toronto, ON, Canada.
- Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada.
- Translational Addiction Research Laboratory, Centre for Addiction and Mental Health, Toronto, ON, Canada.
- Department of Psychiatry, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
- Addictions Division, Centre for Addiction and Mental Health, Toronto, ON, Canada.
- Department of Family and Community Medicine, University of Toronto, Toronto, ON, Canada.
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Lapa GB, Lapa AA. Synthesis and biological evaluation of new N-substituted 4-(arylmethoxy)piperidines as dopamine transporter inhibitors. MENDELEEV COMMUNICATIONS 2019. [DOI: 10.1016/j.mencom.2019.03.030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Behavioral economic analysis of the effects of N-substituted benztropine analogs on cocaine self-administration in rats. Psychopharmacology (Berl) 2018; 235:47-58. [PMID: 28932889 DOI: 10.1007/s00213-017-4739-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Accepted: 09/12/2017] [Indexed: 10/18/2022]
Abstract
RATIONALE AND OBJECTIVES Benztropine (BZT) analogs and other atypical dopamine uptake inhibitors selectively decrease cocaine self-administration at doses that do not affect responding maintained by other reinforcers. Those effects were further characterized in the current study using a behavioral economic assessment of how response requirement (price) affects reinforcers obtained (consumption) in rats. METHODS Two groups of rats were trained to press levers with food (45-mg pellet) or cocaine (0.32 mg/kg/injection) reinforcement under fixed-ratio (FR) 5-response schedules. In selected sessions, the FR requirement was increased (5-80) during successive 20-min components to determine demand curves, which plot consumption against price. An exponential function was fitted to the data to derive the consumption at zero price (Q 0) and the rate of decrease in consumption (essential value, EV) with increased price. The BZT analogs, AHN1-055, AHN2-005, JHW007 (3.2-10 or 17.8 mg/kg, each), vehicle, or comparison drugs (methylphenidate, ketamine), were administered i.p. before selected demand-curve determinations. RESULTS Consumption of cocaine or food decreased with increased FR requirement. Each drug shifted the demand curve rightward at the lowest doses and leftward/downward at higher doses. The effects on EV and Q 0 were greater for cocaine than for food-reinforced responding. Additionally, the effects of the BZT analogs on EV and Q 0 were greater than those obtained with a standard dopamine transport inhibitor, methylphenidate, and the NMDA antagonist, ketamine (1.0-10.0 mg/kg, each). With these latter drugs, the demand-curve parameters were affected similarly with cocaine and food-maintained responding. CONCLUSIONS The current findings, obtained using a behavioral economic assessment, suggest that BZT analogs selectively decrease the reinforcing effectiveness of cocaine.
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Brutcher RE, Nader SH, Nader MA. Evaluation of the Reinforcing Effect of Quetiapine, Alone and in Combination with Cocaine, in Rhesus Monkeys. J Pharmacol Exp Ther 2016; 356:244-50. [PMID: 26644281 PMCID: PMC4727159 DOI: 10.1124/jpet.115.228577] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 12/03/2015] [Indexed: 12/22/2022] Open
Abstract
There are several case reports of nonmedicinal quetiapine abuse, yet there are very limited preclinical studies investigating quetiapine self-administration. The goal of this study was to investigate the reinforcing effects of quetiapine alone and in combination with intravenous cocaine in monkeys. In experiment 1, cocaine-experienced female monkeys (N = 4) responded under a fixed-ratio (FR) 30 schedule of food reinforcement (1.0-g banana-flavored pellets), and when responding was stable, quetiapine (0.003-0.1 mg/kg per injection) or saline was substituted for a minimum of five sessions; there was a return to food-maintained responding between doses. Next, monkeys were treated with quetiapine (25 mg, by mouth, twice a day) for approximately 30 days, and then the quetiapine self-administration dose-response curve was redetermined. In experiment 2, male monkeys (N = 6) self-administered cocaine under a concurrent FR schedule with food reinforcement (three food pellets) as the alternative to cocaine (0.003-0.3 mg/kg per injection) presentation. Once choice responding was stable, the effects of adding quetiapine (0.03 or 0.1 mg/kg per injection) to the cocaine solution were examined. In experiment 1, quetiapine did not function as a reinforcer, and chronic quetiapine treatment did not alter these effects. In experiment 2, cocaine choice increased in a dose-dependent fashion. The addition of quetiapine to cocaine resulted in increases in low-dose cocaine choice and number of cocaine injections in four monkeys, while not affecting high-dose cocaine preference. Thus, although quetiapine alone does not have abuse potential, there was evidence of enhancement of the reinforcing potency of cocaine. These results suggest that the use of quetiapine in cocaine-addicted patients should be monitored.
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Affiliation(s)
- Robert E Brutcher
- Center for Neurobiology of Addiction Treatment, Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Susan H Nader
- Center for Neurobiology of Addiction Treatment, Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Michael A Nader
- Center for Neurobiology of Addiction Treatment, Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina
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Hong WC, Kopajtic TA, Xu L, Lomenzo SA, Jean B, Madura JD, Surratt CK, Trudell ML, Katz JL. 2-Substituted 3β-Aryltropane Cocaine Analogs Produce Atypical Effects without Inducing Inward-Facing Dopamine Transporter Conformations. J Pharmacol Exp Ther 2016; 356:624-34. [PMID: 26769919 DOI: 10.1124/jpet.115.230722] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 01/07/2016] [Indexed: 11/22/2022] Open
Abstract
Previous structure-activity relationship studies indicate that a series of cocaine analogs, 3β-aryltropanes with 2β-diarylmethoxy substituents, selectively bind to the dopamine transporter (DAT) with nanomolar affinities that are 10-fold greater than the affinities of their corresponding 2α-enantiomers. The present study compared these compounds to cocaine with respect to locomotor effects in mice, and assessed their ability to substitute for cocaine (10 mg/kg, i.p.) in rats trained to discriminate cocaine from saline. Despite nanomolar DAT affinity, only the 2β-Ph2COCH2-3β-4-Cl-Ph analog fully substituted for cocaine-like discriminative effects. Whereas all of the 2β compounds increased locomotion, only the 2β-(4-ClPh)PhCOCH2-3β-4-Cl-Ph analog had cocaine-like efficacy. None of the 2α-substituted compounds produced either of these cocaine-like effects. To explore the molecular mechanisms of these drugs, their effects on DAT conformation were probed using a cysteine-accessibility assay. Previous reports indicate that cocaine binds with substantially higher affinity to the DAT in its outward (extracellular)- compared with inward-facing conformation, whereas atypical DAT inhibitors, such as benztropine, have greater similarity in affinity to these conformations, and this is postulated to explain their divergent behavioral effects. All of the 2β- and 2α-substituted compounds tested altered cysteine accessibility of DAT in a manner similar to cocaine. Furthermore, molecular dynamics of in silico inhibitor-DAT complexes suggested that the 2-substituted compounds reach equilibrium in the binding pocket in a cocaine-like fashion. These behavioral, biochemical, and computational results show that aryltropane analogs can bind to the DAT and stabilize outward-facing DAT conformations like cocaine, yet produce effects that differ from those of cocaine.
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Affiliation(s)
- Weimin C Hong
- Department of Pharmaceutical Sciences, Butler University, Indianapolis, Indiana (W.C.H.); Psychobiology Section (T.A.K., J.L.K.), Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland; Chemistry Department (L.X., S.A.L., M.L.T.), University of New Orleans, New Orleans, Louisiana; Department of Chemistry and Biochemistry (B.J., J.D.M.) and Division of Pharmaceutical Sciences (C.K.S.), Duquesne University, Pittsburgh, Pennsylvania
| | - Theresa A Kopajtic
- Department of Pharmaceutical Sciences, Butler University, Indianapolis, Indiana (W.C.H.); Psychobiology Section (T.A.K., J.L.K.), Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland; Chemistry Department (L.X., S.A.L., M.L.T.), University of New Orleans, New Orleans, Louisiana; Department of Chemistry and Biochemistry (B.J., J.D.M.) and Division of Pharmaceutical Sciences (C.K.S.), Duquesne University, Pittsburgh, Pennsylvania
| | - Lifen Xu
- Department of Pharmaceutical Sciences, Butler University, Indianapolis, Indiana (W.C.H.); Psychobiology Section (T.A.K., J.L.K.), Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland; Chemistry Department (L.X., S.A.L., M.L.T.), University of New Orleans, New Orleans, Louisiana; Department of Chemistry and Biochemistry (B.J., J.D.M.) and Division of Pharmaceutical Sciences (C.K.S.), Duquesne University, Pittsburgh, Pennsylvania
| | - Stacey A Lomenzo
- Department of Pharmaceutical Sciences, Butler University, Indianapolis, Indiana (W.C.H.); Psychobiology Section (T.A.K., J.L.K.), Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland; Chemistry Department (L.X., S.A.L., M.L.T.), University of New Orleans, New Orleans, Louisiana; Department of Chemistry and Biochemistry (B.J., J.D.M.) and Division of Pharmaceutical Sciences (C.K.S.), Duquesne University, Pittsburgh, Pennsylvania
| | - Bernandie Jean
- Department of Pharmaceutical Sciences, Butler University, Indianapolis, Indiana (W.C.H.); Psychobiology Section (T.A.K., J.L.K.), Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland; Chemistry Department (L.X., S.A.L., M.L.T.), University of New Orleans, New Orleans, Louisiana; Department of Chemistry and Biochemistry (B.J., J.D.M.) and Division of Pharmaceutical Sciences (C.K.S.), Duquesne University, Pittsburgh, Pennsylvania
| | - Jeffry D Madura
- Department of Pharmaceutical Sciences, Butler University, Indianapolis, Indiana (W.C.H.); Psychobiology Section (T.A.K., J.L.K.), Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland; Chemistry Department (L.X., S.A.L., M.L.T.), University of New Orleans, New Orleans, Louisiana; Department of Chemistry and Biochemistry (B.J., J.D.M.) and Division of Pharmaceutical Sciences (C.K.S.), Duquesne University, Pittsburgh, Pennsylvania
| | - Christopher K Surratt
- Department of Pharmaceutical Sciences, Butler University, Indianapolis, Indiana (W.C.H.); Psychobiology Section (T.A.K., J.L.K.), Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland; Chemistry Department (L.X., S.A.L., M.L.T.), University of New Orleans, New Orleans, Louisiana; Department of Chemistry and Biochemistry (B.J., J.D.M.) and Division of Pharmaceutical Sciences (C.K.S.), Duquesne University, Pittsburgh, Pennsylvania
| | - Mark L Trudell
- Department of Pharmaceutical Sciences, Butler University, Indianapolis, Indiana (W.C.H.); Psychobiology Section (T.A.K., J.L.K.), Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland; Chemistry Department (L.X., S.A.L., M.L.T.), University of New Orleans, New Orleans, Louisiana; Department of Chemistry and Biochemistry (B.J., J.D.M.) and Division of Pharmaceutical Sciences (C.K.S.), Duquesne University, Pittsburgh, Pennsylvania
| | - Jonathan L Katz
- Department of Pharmaceutical Sciences, Butler University, Indianapolis, Indiana (W.C.H.); Psychobiology Section (T.A.K., J.L.K.), Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland; Chemistry Department (L.X., S.A.L., M.L.T.), University of New Orleans, New Orleans, Louisiana; Department of Chemistry and Biochemistry (B.J., J.D.M.) and Division of Pharmaceutical Sciences (C.K.S.), Duquesne University, Pittsburgh, Pennsylvania
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Reith ME, Blough BE, Hong WC, Jones KT, Schmitt KC, Baumann MH, Partilla JS, Rothman RB, Katz JL. Behavioral, biological, and chemical perspectives on atypical agents targeting the dopamine transporter. Drug Alcohol Depend 2015; 147:1-19. [PMID: 25548026 PMCID: PMC4297708 DOI: 10.1016/j.drugalcdep.2014.12.005] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 12/04/2014] [Accepted: 12/04/2014] [Indexed: 10/24/2022]
Abstract
BACKGROUND Treatment of stimulant-use disorders remains a formidable challenge, and the dopamine transporter (DAT) remains a potential target for antagonist or agonist-like substitution therapies. METHODS This review focuses on DAT ligands, such as benztropine, GBR 12909, modafinil, and DAT substrates derived from phenethylamine or cathinone that have atypical DAT-inhibitor effects, either in vitro or in vivo. The compounds are described from a molecular mechanistic, behavioral, and medicinal-chemical perspective. RESULTS Possible mechanisms for atypicality at the molecular level can be deduced from the conformational cycle for substrate translocation. For each conformation, a crystal structure of a bacterial homolog is available, with a possible role of cholesterol, which is also present in the crystal of Drosophila DAT. Although there is a direct relationship between behavioral potencies of most DAT inhibitors and their DAT affinities, a number of compounds bind to the DAT and inhibit dopamine uptake but do not share cocaine-like effects. Such atypical behavior, depending on the compound, may be related to slow DAT association, combined sigma-receptor actions, or bias for cytosol-facing DAT. Some structures are sterically small enough to serve as DAT substrates but large enough to also inhibit transport. Such compounds may display partial DA releasing effects, and may be combined with release or uptake inhibition at other monoamine transporters. CONCLUSIONS Mechanisms of atypical DAT inhibitors may serve as targets for the development of treatments for stimulant abuse. These mechanisms are novel and their further exploration may produce compounds with unique therapeutic potential as treatments for stimulant abuse.
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Affiliation(s)
- Maarten E.A. Reith
- Department of Psychiatry, New York University School of Medicine, New York, NY 10016, USA,Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA,Corresponding author: Maarten E.A. Reith, Department of Psychiatry, Alexandria Center of Life Sciences, New York University School of Medicine, 450 E 29th Street, Room 803, New York, NY 10016. Tel.: 212 - 263 8267; Fax: 212 – 263 8183;
| | - Bruce E. Blough
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, NC 27709, USA
| | - Weimin C. Hong
- Psychobiology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, USA
| | - Kymry T. Jones
- Department of Psychiatry, New York University School of Medicine, New York, NY 10016, USA
| | - Kyle C. Schmitt
- Department of Psychiatry, New York University School of Medicine, New York, NY 10016, USA
| | - Michael H. Baumann
- Medicinal Chemistry Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, USA
| | - John S. Partilla
- Medicinal Chemistry Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, USA
| | - Richard B. Rothman
- Medicinal Chemistry Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, USA
| | - Jonathan L. Katz
- Psychobiology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, USA
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Kohut SJ, Hiranita T, Hong SK, Ebbs AL, Tronci V, Green J, Garcés-Ramírez L, Chun LE, Mereu M, Newman AH, Katz JL, Tanda G. Preference for distinct functional conformations of the dopamine transporter alters the relationship between subjective effects of cocaine and stimulation of mesolimbic dopamine. Biol Psychiatry 2014; 76:802-9. [PMID: 24853388 PMCID: PMC4353924 DOI: 10.1016/j.biopsych.2014.03.031] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 03/08/2014] [Accepted: 03/13/2014] [Indexed: 11/26/2022]
Abstract
BACKGROUND Subjective effects of cocaine are mediated primarily by dopamine (DA) transporter (DAT) blockade. The present study assessed the hypothesis that different DAT conformational equilibria regulate differences in cocaine-like subjective effects and extracellular DA induced by diverse DA-uptake inhibitors (DUIs). METHODS The relationship between cocaine-like subjective effects and stimulation of mesolimbic DA levels by standard DUIs (cocaine, methylphenidate, WIN35,428) and atypical DUIs (benztropine analogs: AHN1-055, AHN2-005, JHW007) was investigated using cocaine discrimination and DA microdialysis procedures in rats. RESULTS All drugs stimulated DA levels with different maxima and time courses. Standard DUIs, which preferentially bind outward-facing DAT conformations, fully substituted for cocaine, consistently producing cocaine-like subjective effects at DA levels of 100-125% over basal values, regardless of dose or pretreatment time. The atypical DUIs, with DAT binding minimally affected by DAT conformation, produced inconsistent cocaine-like subjective effects. Full effects were obtained, if at all, only at a few doses and pretreatment times and at DA levels 600-700% greater than basal values. Importantly, the linear, time-independent, relationship between cocaine-like subjective effects and DA stimulation obtained with standard DUIs was not obtained with the atypical DUIs. CONCLUSIONS These results suggest a time-related desensitization process underlying the reduced cocaine subjective effects of atypical DUIs that may be differentially induced by the binding modalities identified using molecular approaches. Since the DAT is the target of several drugs for treating neuropsychiatric disorders, such as attention-deficit/hyperactivity disorder, these results help to identify safe and effective medications with minimal cocaine-like subjective effects that contribute to abuse liability.
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Affiliation(s)
- Stephen J Kohut
- Psychobiology, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse/Intramural Research Program/National Institutes of Health/Department of Health and Human Services, Baltimore, Maryland
| | - Takato Hiranita
- Psychobiology, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse/Intramural Research Program/National Institutes of Health/Department of Health and Human Services, Baltimore, Maryland
| | - Soo-Kyung Hong
- Psychobiology, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse/Intramural Research Program/National Institutes of Health/Department of Health and Human Services, Baltimore, Maryland; Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Aaron L Ebbs
- Psychobiology, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse/Intramural Research Program/National Institutes of Health/Department of Health and Human Services, Baltimore, Maryland
| | - Valeria Tronci
- Psychobiology, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse/Intramural Research Program/National Institutes of Health/Department of Health and Human Services, Baltimore, Maryland
| | - Jennifer Green
- Psychobiology, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse/Intramural Research Program/National Institutes of Health/Department of Health and Human Services, Baltimore, Maryland
| | - Linda Garcés-Ramírez
- Psychobiology, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse/Intramural Research Program/National Institutes of Health/Department of Health and Human Services, Baltimore, Maryland; Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, México
| | - Lauren E Chun
- Psychobiology, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse/Intramural Research Program/National Institutes of Health/Department of Health and Human Services, Baltimore, Maryland
| | - Maddalena Mereu
- Psychobiology, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse/Intramural Research Program/National Institutes of Health/Department of Health and Human Services, Baltimore, Maryland
| | - Amy H Newman
- Medicinal Chemistry Sections, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse/Intramural Research Program/National Institutes of Health/Department of Health and Human Services, Baltimore, Maryland; Medications Development Program, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse/Intramural Research Program/National Institutes of Health/Department of Health and Human Services, Baltimore, Maryland
| | - Jonathan L Katz
- Psychobiology, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse/Intramural Research Program/National Institutes of Health/Department of Health and Human Services, Baltimore, Maryland
| | - Gianluigi Tanda
- Psychobiology, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse/Intramural Research Program/National Institutes of Health/Department of Health and Human Services, Baltimore, Maryland; Medications Development Program, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse/Intramural Research Program/National Institutes of Health/Department of Health and Human Services, Baltimore, Maryland.
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Hiranita T, Wilkinson DS, Hong WC, Zou MF, Kopajtic TA, Soto PL, Lupica CR, Newman AH, Katz JL. 2-isoxazol-3-phenyltropane derivatives of cocaine: molecular and atypical system effects at the dopamine transporter. J Pharmacol Exp Ther 2014; 349:297-309. [PMID: 24518035 DOI: 10.1124/jpet.113.212738] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The present study examined RTI-371 [3β-(4-methylphenyl)-2β-[3-(4-chlorophenyl)-isoxazol-5-yl]tropane], a phenyltropane cocaine analog with effects distinct from cocaine, and assessed potential mechanisms for those effects by comparison with its constitutional isomer, RTI-336 [3β-(4-chlorophenyl)-2β-[3-(4-methylphenyl)-isoxazol-5-yl]tropane]. In mice, RTI-371 was less effective than cocaine and RTI-336 in stimulating locomotion, and incompletely substituted (∼60% maximum at 5 minutes or 1 hour after injection) in a cocaine (10 mg/kg i.p.)/saline discrimination procedure; RTI-336 completely substituted. In contrast to RTI-336, RTI-371 was not self-administered, and its pretreatment (1.0-10 mg/kg i.p.) dose-dependently decreased maximal cocaine self-administration more potently than food-maintained responding. RTI-336 pretreatment dose-dependently left-shifted the cocaine self-administration dose-effect curve. Both RTI-336 and RTI-371 displaced [(3)H]WIN35,428 [[(3)H](-)-3β-(4-fluorophenyl)-tropan-2β-carboxylic acid methyl ester tartrate] binding to striatal dopamine transporters (DATs) with Ki values of 10.8 and 7.81 nM, respectively, and had lower affinities at serotonin or norepinephrine transporters, or muscarinic and σ receptors. The relative low affinity at these sites suggests the DAT as the primary target of RTI-371 with minimal contributions from these other targets. In biochemical assays probing the outward-facing DAT conformation, both RTI-371 and RTI-336 had effects similar to cocaine, suggesting little contribution of DAT conformation to the unique pharmacology of RTI-371. The locomotor-stimulant effects of RTI-371 (3.0-30 mg/kg i.p.) were comparable in wild-type and knockout cannabinoid CB1 receptor (CB1R) mice, indicating that previously reported CB1 allosteric effects do not decrease cocaine-like effects of RTI-371. DAT occupancy in vivo was most rapid with cocaine and least with RTI-371. The slow apparent association rate may allow compensatory actions that in turn dampen cocaine-like stimulation, and give RTI-371 its unique pharmacologic profile.
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Affiliation(s)
- Takato Hiranita
- Psychobiology (T.H., D.S.W., T.A.K., J.L.K.), Cellular Pathobiology Section (W.C.H.), Medicinal Chemistry (M.F.Z., A.H.N.), and Electrophysiology (C.R.L.) Sections, Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland; and Texas Tech University, College of Education, Lubbock, Texas (P.L.S.)
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Desai RI, Grandy DK, Lupica CR, Katz JL. Pharmacological characterization of a dopamine transporter ligand that functions as a cocaine antagonist. J Pharmacol Exp Ther 2013; 348:106-15. [PMID: 24194528 DOI: 10.1124/jpet.113.208538] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
An N-butyl analog of benztropine, JHW007 [N-(n-butyl)-3α-[bis(4'-fluorophenyl)methoxy]-tropane], binds to dopamine transporters (DAT) but has reduced cocaine-like behavioral effects and antagonizes various effects of cocaine. The present study further examined mechanisms underlying these effects. Cocaine dose-dependently increased locomotion, whereas JHW007 was minimally effective but increased activity 24 hours after injection. JHW007 (3-10 mg/kg) dose-dependently and fully antagonized the locomotor-stimulant effects of cocaine (5-60 mg/kg), whereas N-methyl and N-allyl analogs and the dopamine (DA) uptake inhibitor GBR12909 [1-(2-[bis(4-fluorophenyl)methoxy]ethyl)-4-(3-phenylpropyl)piperazine dihydrochloride] stimulated activity and failed to antagonize effects of cocaine. JHW007 also blocked the locomotor-stimulant effects of the DAT inhibitor GBR12909 but not stimulation produced by the δ-opioid agonist SNC 80 [4-[(R)-[(2S,5R)-4-allyl-2,5-dimethylpiperazin-1-yl](3-methoxyphenyl)methyl]-N,N-diethylbenzamide], which increases activity through nondopaminergic mechanisms. JHW007 blocked locomotor-stimulant effects of cocaine in both DA D2- and CB1-receptor knockout and wild-type mice, indicating a lack of involvement of these targets. Furthermore, JHW007 blocked effects of cocaine on stereotyped rearing but enhanced stereotyped sniffing, suggesting that interference with locomotion by enhanced stereotypies is not responsible for the cocaine-antagonist effects of JHW007. Time-course data indicate that administration of JHW007 antagonized the locomotor-stimulant effects of cocaine within 10 minutes of injection, whereas occupancy at the DAT, as determined in vivo, did not reach a maximum until 4.5 hours after injection. The σ1-receptor antagonist BD 1008 [N-[2-(3,4-dichlorophenyl)ethyl]-N-methyl-2-(1-pyrrolidinyl)ethylamine dihydrobromide] blocked the locomotor-stimulant effects of cocaine. Overall, these findings suggest that JHW007 has cocaine-antagonist effects that are deviate from its DAT occupancy and that some other mechanism, possibly σ-receptor antagonist activity, may contribute to the cocaine-antagonist effect of JHW007 and like drugs.
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Affiliation(s)
- Rajeev I Desai
- Psychobiology Section (R.I.D., J.L.K.) and Electrophysiology Research Section (C.R.L.), National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland; and Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon (D.K.G.)
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Mereu M, Bonci A, Newman AH, Tanda G. The neurobiology of modafinil as an enhancer of cognitive performance and a potential treatment for substance use disorders. Psychopharmacology (Berl) 2013; 229:415-34. [PMID: 23934211 PMCID: PMC3800148 DOI: 10.1007/s00213-013-3232-4] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 07/28/2013] [Indexed: 12/31/2022]
Abstract
RATIONALE AND OBJECTIVES Modafinil (MOD) and its R-enantiomer (R-MOD) are approved medications for narcolepsy and other sleep disorders. They have also been used, off-label, as cognitive enhancers in populations of patients with mental disorders, including substance abusers that demonstrate impaired cognitive function. A debated nonmedical use of MOD in healthy individuals to improve intellectual performance is raising questions about its potential abuse liability in this population. RESULTS AND CONCLUSIONS MOD has low micromolar affinity for the dopamine transporter (DAT). Inhibition of dopamine (DA) reuptake via the DAT explains the enhancement of DA levels in several brain areas, an effect shared with psychostimulants like cocaine, methylphenidate, and the amphetamines. However, its neurochemical effects and anatomical pattern of brain area activation differ from typical psychostimulants and are consistent with its beneficial effects on cognitive performance processes such as attention, learning, and memory. At variance with typical psychostimulants, MOD shows very low, if any, abuse liability, in spite of its use as a cognitive enhancer by otherwise healthy individuals. Finally, recent clinical studies have focused on the potential use of MOD as a medication for treatment of drug abuse, but have not shown consistent outcomes. However, positive trends in several result measures suggest that medications that improve cognitive function, like MOD or R-MOD, may be beneficial for the treatment of substance use disorders in certain patient populations.
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Affiliation(s)
- Maddalena Mereu
- Molecular Targets & Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, DHHS; 251 Bayview Blvd., NIDA suite 200, Baltimore, MD, 21224
| | - Antonello Bonci
- Synaptic Plasticity Section, Cellular Neurobiology Research Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, DHHS; 251 Bayview Blvd., NIDA suite 200, Baltimore, MD, 21224
| | - Amy Hauck Newman
- Molecular Targets & Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, DHHS; 251 Bayview Blvd., NIDA suite 200, Baltimore, MD, 21224
| | - Gianluigi Tanda
- Molecular Targets & Medication Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, DHHS; 251 Bayview Blvd., NIDA suite 200, Baltimore, MD, 21224
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Tanda G, Li SM, Mereu M, Thomas AM, Ebbs AL, Chun LE, Tronci V, Green JL, Zou MF, Kopajtic TA, Newman AH, Katz JL. Relations between stimulation of mesolimbic dopamine and place conditioning in rats produced by cocaine or drugs that are tolerant to dopamine transporter conformational change. Psychopharmacology (Berl) 2013; 229:307-21. [PMID: 23612854 PMCID: PMC3758386 DOI: 10.1007/s00213-013-3109-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Accepted: 04/05/2013] [Indexed: 10/26/2022]
Abstract
RATIONALE Dopamine transporter (DAT) conformation plays a role in the effectiveness of cocaine-like and other DAT inhibitors. Cocaine-like stimulants are intolerant to DAT conformation changes having decreased potency in cells transfected with DAT constructs that face the cytosol compared to wild-type DAT. In contrast, analogs of benztropine (BZT) are among compounds that are less affected by DAT conformational change. METHODS We compared the displacement of radioligand binding to various mammalian CNS sites, acute stimulation of accumbens shell dopamine levels, and place conditioning in rats among cocaine and four BZT analogs with Cl substitutions on the diphenyl-ether system including two with carboalkoxy substitutions at the 2-position of the tropane ring. RESULTS Binding assays confirmed high-affinity and selectivity for the DAT with the BZT analogs which also produced significant stimulation of mesolimbic dopamine efflux. Because BZT analogs produced temporal patterns of extracellular dopamine levels different from those by cocaine (3-10 mg/kg, i.p.), the place conditioning produced by BZT analogs and cocaine was compared at doses and times at which both the increase in dopamine levels and rates of increase were similar to those produced by an effective dose of cocaine. Despite this equilibration, none of the BZT analogs tested produced significant place conditioning. CONCLUSIONS The present results extend previous findings suggesting that cocaine-like actions are dependent on a binding equilibrium that favors the outward conformational state of the DAT. In contrast, BZT analogs with reduced dependence on DAT conformation have reduced cocaine-like behavioral effects and may prove useful in development of medications for stimulant abuse.
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Affiliation(s)
- Gianluigi Tanda
- Psychobiology Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health; 251 Bayview Blvd., NIDA suite 200, Baltimore, MD, 21224
| | - Su Min Li
- Psychobiology Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health; 251 Bayview Blvd., NIDA suite 200, Baltimore, MD, 21224
| | - Maddalena Mereu
- Psychobiology Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health; 251 Bayview Blvd., NIDA suite 200, Baltimore, MD, 21224
| | - Alexandra M. Thomas
- Psychobiology Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health; 251 Bayview Blvd., NIDA suite 200, Baltimore, MD, 21224
| | - Aaron L. Ebbs
- Psychobiology Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health; 251 Bayview Blvd., NIDA suite 200, Baltimore, MD, 21224
| | | | - Valeria Tronci
- Psychobiology Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health; 251 Bayview Blvd., NIDA suite 200, Baltimore, MD, 21224
| | - Jennifer L. Green
- Psychobiology Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health; 251 Bayview Blvd., NIDA suite 200, Baltimore, MD, 21224
| | - Mu-Fa Zou
- Medicinal Chemistry Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health; 251 Bayview Blvd., NIDA suite 200, Baltimore, MD, 21224
| | - Theresa A. Kopajtic
- Psychobiology Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health; 251 Bayview Blvd., NIDA suite 200, Baltimore, MD, 21224
| | - Amy Hauck Newman
- Medicinal Chemistry Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health; 251 Bayview Blvd., NIDA suite 200, Baltimore, MD, 21224
| | - Jonathan L. Katz
- Psychobiology Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health; 251 Bayview Blvd., NIDA suite 200, Baltimore, MD, 21224
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Reith MEA, Ali S, Hashim A, Sheikh IS, Theddu N, Gaddiraju NV, Mehrotra S, Schmitt KC, Murray TF, Sershen H, Unterwald EM, Davis FA. Novel C-1 substituted cocaine analogs unlike cocaine or benztropine. J Pharmacol Exp Ther 2012; 343:413-25. [PMID: 22895898 DOI: 10.1124/jpet.112.193771] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Despite a wealth of information on cocaine-like compounds, there is no information on cocaine analogs with substitutions at C-1. Here, we report on (R)-(-)-cocaine analogs with various C-1 substituents: methyl (2), ethyl (3), n-propyl (4), n-pentyl (5), and phenyl (6). Analog 2 was equipotent to cocaine as an inhibitor of the dopamine transporter (DAT), whereas 3 and 6 were 3- and 10-fold more potent, respectively. None of the analogs, however, stimulated mouse locomotor activity, in contrast to cocaine. Pharmacokinetic assays showed compound 2 occupied mouse brain rapidly, as cocaine itself; moreover, 2 and 6 were behaviorally active in mice in the forced-swim test model of depression and the conditioned place preference test. Analog 2 was a weaker inhibitor of voltage-dependent Na+ channels than cocaine, although 6 was more potent than cocaine, highlighting the need to assay future C-1 analogs for this activity. Receptorome screening indicated few significant binding targets other than the monoamine transporters. Benztropine-like "atypical" DAT inhibitors are known to display reduced cocaine-like locomotor stimulation, presumably by their propensity to interact with an inward-facing transporter conformation. However, 2 and 6, like cocaine, but unlike benztropine, exhibited preferential interaction with an outward-facing conformation upon docking in our DAT homology model. In summary, C-1 cocaine analogs are not cocaine-like in that they are not stimulatory in vivo. However, they are not benztropine-like in binding mechanism and seem to interact with the DAT similarly to cocaine. The present data warrant further consideration of these novel cocaine analogs for antidepressant or cocaine substitution potential.
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Affiliation(s)
- Maarten E A Reith
- Department of Psychiatry, New York University School of Medicine, 450 E 29th Street, Alexandria Building Room 803, New York, NY 10016, USA.
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The atypical stimulant and nootropic modafinil interacts with the dopamine transporter in a different manner than classical cocaine-like inhibitors. PLoS One 2011; 6:e25790. [PMID: 22043293 PMCID: PMC3197159 DOI: 10.1371/journal.pone.0025790] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 09/11/2011] [Indexed: 11/19/2022] Open
Abstract
Modafinil is a mild psychostimulant with pro-cognitive and antidepressant effects. Unlike many conventional stimulants, modafinil has little appreciable potential for abuse, making it a promising therapeutic agent for cocaine addiction. The chief molecular target of modafinil is the dopamine transporter (DAT); however, the mechanistic details underlying modafinil's unique effects remain unknown. Recent studies suggest that the conformational effects of a given DAT ligand influence the magnitude of the ligand's reinforcing properties. For example, the atypical DAT inhibitors benztropine and GBR12909 do not share cocaine's notorious addictive liability, despite having greater binding affinity. Here, we show that the binding mechanism of modafinil is different than cocaine and similar to other atypical inhibitors. We previously established two mutations (W84L and D313N) that increase the likelihood that the DAT will adopt an outward-facing conformational state—these mutations increase the affinity of cocaine-like inhibitors considerably, but have little or opposite effect on atypical inhibitor binding. Thus, a compound's WT/mutant affinity ratio can indicate whether the compound preferentially interacts with a more outward- or inward-facing conformational state. Modafinil displayed affinity ratios similar to those of benztropine, GBR12909 and bupropion (which lack cocaine-like effects in humans), but far different than those of cocaine, β-CFT or methylphenidate. Whereas treatment with zinc (known to stabilize an outward-facing transporter state) increased the affinity of cocaine and methylphenidate two-fold, it had little or no effect on the binding of modafinil, benztropine, bupropion or GBR12909. Additionally, computational modeling of inhibitor binding indicated that while β-CFT and methylphenidate stabilize an “open-to-out” conformation, binding of either modafinil or bupropion gives rise to a more closed conformation. Our findings highlight a mechanistic difference between modafinil and cocaine-like stimulants and further demonstrate that the conformational effects of a given DAT inhibitor influence its phenomenological effects.
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Li SM, Kopajtic TA, O'Callaghan MJ, Agoston GE, Cao J, Newman AH, Katz JL. N-substituted benztropine analogs: selective dopamine transporter ligands with a fast onset of action and minimal cocaine-like behavioral effects. J Pharmacol Exp Ther 2010; 336:575-85. [PMID: 21088247 DOI: 10.1124/jpet.110.173260] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Previous studies suggested that differences between the behavioral effects of cocaine and analogs of benztropine were related to the relatively slow onset of action of the latter compounds. Several N-substituted benztropine analogs with a relatively fast onset of effects were studied to assess whether a fast onset of effects would render the effects more similar to those of cocaine. Only one of the compounds increased locomotor activity, and the increases were modest compared with those of 10 to 20 mg/kg cocaine. In rats trained to discriminate 10 mg/kg cocaine from saline none of the compounds produced more than 40% cocaine-like responds up to 2 h after injection. None of the compounds produced place-conditioning when examined up to 90 min after injection, indicating minimal abuse liability. The compounds had 5.6 to 30 nM affinities at the dopamine transporter (DAT), with uniformly lower affinities at norepinephrine and serotonin transporters (from 490-4600 and 1420-7350 nM, respectively). Affinities at muscarinic M(1) receptors were from 100- to 300-fold lower than DAT affinities, suggesting minimal contribution of those sites to the behavioral effects of the compounds. Affinities at histaminic H(1) sites were from 11- to 43-fold lower than those for the DAT. The compounds also had affinity for sigma, 5-hydroxytryptamine(1) (5-HT(1)), and 5-HT(2) receptors that may have contributed to their behavioral effects. Together, the results indicate that a slow onset of action is not a necessary condition for reduced cocaine-like effects of atypical DAT ligands and suggest several mechanisms that may contribute to the reduced cocaine-like efficacy of these compounds.
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Affiliation(s)
- Su-Min Li
- Sections, Medications Discovery Research Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland 21224, USA
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Involvement of the brain histaminergic system in addiction and addiction-related behaviors: a comprehensive review with emphasis on the potential therapeutic use of histaminergic compounds in drug dependence. Prog Neurobiol 2010; 92:421-41. [PMID: 20638439 DOI: 10.1016/j.pneurobio.2010.07.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 07/01/2010] [Accepted: 07/10/2010] [Indexed: 01/13/2023]
Abstract
Neurons that produce histamine are exclusively located in the tuberomamillary nucleus of the posterior hypothalamus and send widespread projections to almost all brain areas. Neuronal histamine is involved in many physiological and behavioral functions such as arousal, feeding behavior and learning. Although conflicting data have been published, several studies have also demonstrated a role of histamine in the psychomotor and rewarding effects of addictive drugs. Pharmacological and brain lesion experiments initially led to the proposition that the histaminergic system exerts an inhibitory influence on drug reward processes, opposed to that of the dopaminergic system. The purpose of this review is to summarize the relevant literature on this topic and to discuss whether the inhibitory function of histamine on drug reward is supported by current evidence from published results. Research conducted during the past decade demonstrated that the ability of many antihistaminic drugs to potentiate addiction-related behaviors essentially results from non-specific effects and does not constitute a valid argument in support of an inhibitory function of histamine on reward processes. The reviewed findings also indicate that histamine can either stimulate or inhibit the dopamine mesolimbic system through distinct neuronal mechanisms involving different histamine receptors. Finally, the hypothesis that the histaminergic system plays an inhibitory role on drug reward appears to be essentially supported by place conditioning studies that focused on morphine reward. The present review suggests that the development of drugs capable of activating the histaminergic system may offer promising therapeutic tools for the treatment of opioid dependence.
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Tanda G, Newman AH, Katz JL. Discovery of drugs to treat cocaine dependence: behavioral and neurochemical effects of atypical dopamine transport inhibitors. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2009; 57:253-89. [PMID: 20230764 PMCID: PMC6768413 DOI: 10.1016/s1054-3589(08)57007-4] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Stimulant drugs acting at the dopamine transporter (DAT), like cocaine, are widely abused, yet effective medical treatments for this abuse have not been found. Analogs of benztropine (BZT) that, like cocaine, act at the DAT have effects that differ from cocaine and in some situations block the behavioral, neurochemical, and reinforcing actions of cocaine. Neurochemical studies of dopamine levels in brain and behavioral studies have demonstrated that BZT analogs have a relatively slow onset and reduced maximal effects compared to cocaine. Pharmacokinetic studies, however, indicated that the BZT analogs rapidly access the brain at concentrations above their in vitro binding affinities, while binding in vivo demonstrates apparent association rates for BZT analogs lower than that for cocaine. Additionally, the off-target effects of these compounds do not fully explain their differences from cocaine. Initial structure-activity studies indicated that BZT analogs bind to DAT differently from cocaine and these differences have been supported by site-directed mutagenesis studies of the DAT. In addition, BZT analog-mediated inhibition of uptake was more resistant to mutations producing inward conformational DAT changes than cocaine analogs. The BZT analogs have provided new insights into the relation between the molecular and behavioral actions of cocaine and the diversity of effects produced by dopamine transport inhibitors. Novel interactions of BZT analogs with the DAT suggest that these drugs may have a pharmacology that would be useful in their development as treatments for cocaine abuse.
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Affiliation(s)
- Gianluigi Tanda
- Medications Discovery Research Branch, Intramural Research Program, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland 21224, USA
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Banks ML, Andersen ML, Murnane KS, Meyer RC, Howell LL. Behavioral and neurochemical effects of cocaine and diphenhydramine combinations in rhesus monkeys. Psychopharmacology (Berl) 2009; 205:467-74. [PMID: 19430765 PMCID: PMC3233267 DOI: 10.1007/s00213-009-1555-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Accepted: 04/22/2009] [Indexed: 11/28/2022]
Abstract
RATIONALE Diphenhydramine (DPH) is an over-the-counter medication used in the treatment of allergic symptoms. While DPH abuse is infrequent, recent preclinical evidence suggests that DPH and cocaine combinations may have enhanced reinforcing properties. OBJECTIVE The aims were to assess the reinforcing effectiveness of cocaine and DPH alone or in combination under a second-order schedule of reinforcement and to examine the neurochemical basis of this interaction using in vivo microdialysis in awake rhesus monkeys. MATERIALS AND METHODS Cocaine (0.03-0.3 mg/kg per injection), DPH (0.3-3.0 mg/kg per injection), or a combination was available under a second-order schedule of intravenous drug reinforcement (n = 3). In microdialysis studies, noncontingent cocaine (0.1-1.0 mg/kg, iv), DPH (1.7 and 3.0 mg/kg, iv), or a combination was administered and changes in extracellular dopamine levels in the caudate nucleus were examined (n = 3-5). RESULTS Cocaine and DPH dose-dependently maintained operant responding. Dose combinations of 1.0 or 1.7 mg/kg per injection DPH and 0.03 mg/kg per injection cocaine maintained greater rates of operant responding than 0.03 mg/kg per injection cocaine alone in the second component of the behavioral session. In microdialysis studies, cocaine dose-dependently increased extracellular dopamine levels, but no dose of DPH tested significantly increased dopamine levels above baseline. Moreover, combining DPH with cocaine did not enhance cocaine-induced dopamine increases. CONCLUSIONS The results support previous evidence of enhanced reinforcement with cocaine and DPH combinations and extend this finding to operant behavior maintained under a second-order schedule. However, the reinforcing effects of DPH alone or in combination with cocaine do not appear to be mediated via changes in dopamine overflow.
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Affiliation(s)
- Matthew L. Banks
- Yerkes National Primate Research Center, Emory University, 954 Gatewood Rd, Atlanta, GA 30329, USA
| | - Monica L. Andersen
- Yerkes National Primate Research Center, Emory University, 954 Gatewood Rd, Atlanta, GA 30329, USA. Department of Psychobiology, Universidade Federal de São Paulo, Escola Paulista de Medicina (UNIFESP/EPM), São Paulo, São Paulo, Brazil
| | - Kevin S. Murnane
- Yerkes National Primate Research Center, Emory University, 954 Gatewood Rd, Atlanta, GA 30329, USA
| | - Rebecca C. Meyer
- Yerkes National Primate Research Center, Emory University, 954 Gatewood Rd, Atlanta, GA 30329, USA
| | - Leonard L. Howell
- Yerkes National Primate Research Center, Emory University, 954 Gatewood Rd, Atlanta, GA 30329, USA. Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA, USA
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Brabant C, Alleva L, Grisar T, Quertemont E, Lakaye B, Ohtsu H, Lin JS, Jatlow P, Picciotto MR, Tirelli E. Effects of the H3 receptor inverse agonist thioperamide on cocaine-induced locomotion in mice: role of the histaminergic system and potential pharmacokinetic interactions. Psychopharmacology (Berl) 2009; 202:673-87. [PMID: 18843481 DOI: 10.1007/s00213-008-1345-y] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Accepted: 09/17/2008] [Indexed: 01/03/2023]
Abstract
RATIONALE Previous studies have shown that intraperitoneal injections of thioperamide, an imidazole-based H3 receptor inverse agonist that enhances histamine release in the brain, potentiate cocaine-induced hyperlocomotion. The present study examined the involvement of the histaminergic system in these effects of thioperamide in mice. MATERIALS AND METHODS We investigated whether immepip, a selective H3 agonist, could reverse the potentiating effects of thioperamide. Moreover, the non-imidazole H3 inverse agonist A-331440 was tested on the locomotor effects of cocaine. Using high-performance liquid chromatography with ultraviolet detection, cocaine plasma concentrations were measured to study potential drug-drug interactions between thioperamide and cocaine. Finally, thioperamide was tested on the locomotor effects of cocaine in histamine-deficient knockout mice in order to determine the contribution of histamine to the modulating effects of thioperamide. RESULTS Thioperamide potentiated cocaine-induced hyperlocomotion in normal mice, and to a higher extent, in histamine-deficient knockout mice. A-331440 only slightly affected the locomotor effects of cocaine. Immepip did not alter cocaine-induced hyperactivity but significantly reduced the potentiating actions of thioperamide on cocaine's effects. Finally, plasma cocaine concentrations were more elevated in mice treated with thioperamide than in mice that received cocaine alone. CONCLUSIONS The present results indicate that histamine released by thioperamide through the blockade of H3 autoreceptors is not involved in the ability of this compound to potentiate cocaine induced-hyperactivity. Our data suggest that thioperamide, at least at 10 mg/kg, increases cocaine-induced locomotion through the combination of pharmacokinetic effects and the blockade of H3 receptors located on non-histaminergic neurons.
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Affiliation(s)
- Christian Brabant
- Centre de Neurosciences Cognitives et Comportementales (CNCC), Université de Liège, Boulevard du Rectorat 5/B-32, 4000 Liège, Belgium
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Atypical Dopamine Uptake Inhibitors that Provide Clues About Cocaine's Mechanism at the Dopamine Transporter. ACTA ACUST UNITED AC 2008. [DOI: 10.1007/7355_2008_027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Wang Z, Woolverton WL. Super-additive interaction of the reinforcing effects of cocaine and H1-antihistamines in rhesus monkeys. Pharmacol Biochem Behav 2008; 91:590-5. [PMID: 18930758 DOI: 10.1016/j.pbb.2008.09.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Revised: 09/25/2008] [Accepted: 09/26/2008] [Indexed: 11/25/2022]
Abstract
Histamine H1 receptor antagonists can be sedating and have behavioral effects, including reinforcing and discriminative stimulus effects in non-humans, that predict abuse liability. Previous research has suggested that antihistamines can enhance the effects of some drugs of abuse. We have reported a synergistic interaction between cocaine and diphenhydramine (DPH) in a self-administration assay with monkeys. The present study was designed to extend those findings to other combinations of cocaine and DPH, and to the mixture of cocaine and another H1-antihistamine, pyrilamine. Rhesus monkeys were prepared with chronic i.v. catheters and allowed to self-administer cocaine, DPH or pyrilamine alone or as mixtures under a progressive-ratio schedule of reinforcement. Cocaine, DPH and pyrilamine alone maintained self-administration and cocaine was the stronger reinforcer. When cocaine was combined with DPH or pyrilamine in a 1:1, 1:2 or 2:1 ratio of the ED(50)s, the combinations were super-additive as reinforcers. Reinforcing strength of the combinations was greater than that of the antihistamines alone but not greater than cocaine. The data support the prediction that the combination of cocaine and histamine H1 receptor antagonists could have enhanced potential for abuse relative to either drug alone. The interaction may involve dopamine systems in the CNS.
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Affiliation(s)
- Zhixia Wang
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, 2500 N. State Street, Jackson, MS 39216, USA
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Tanda G, Kopajtic TA, Katz JL. Cocaine-like neurochemical effects of antihistaminic medications. J Neurochem 2008; 106:147-57. [PMID: 18363822 DOI: 10.1111/j.1471-4159.2008.05361.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The pattern of activation of dopamine (DA) neurotransmission in the nucleus accumbens (NAc) of rats produced by H(1) histamine antagonists which have behavioral effects like those of psychostimulant drugs was examined. Diphenhydramine and (+)-chlorpheniramine were compared with triprolidine, a potent and selective H(1) antagonist and (-)-chlorpheniramine which is less active than its enantiomer at H(1) receptors. Affinities of the drugs to DA, serotonin, and norepinephrine transporters at H(1) receptors and potencies for DA uptake inhibition in striatal synaptosomes were determined to assess mechanisms by which the compounds increased DA levels. Intravenous diphenhydramine (1.0-3.0 mg/kg) (+)- and (-)-chlorpheniramine (1.0-5.6 mg/kg) but not triprolidine (1.0-3.0 mg/kg) elicited a cocaine-like pattern of stimulation of DA transmission with larger effects in the NAc shell than core. The absence of stereospecific effects with chlorpheniramine enantiomers along with the lack of an effect with triprolidine suggest that the effects on DA transmission were not related to H(1) receptor antagonism. Although in vivo potencies were not directly related to DA transporter affinities, it is hypothesized that actions at that site modulated by other actions, possibly those at the serotonin transporter, are primarily responsible for the neurochemical actions of the drugs on DA neurotransmission and might underlie the occasional misuse of these medications.
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Affiliation(s)
- Gianluigi Tanda
- Psychobiology Section, Medications Discovery Research Branch, Department of Health and Human Services, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland 21224, USA.
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Loland CJ, Desai RI, Zou MF, Cao J, Grundt P, Gerstbrein K, Sitte HH, Newman AH, Katz JL, Gether U. Relationship between Conformational Changes in the Dopamine Transporter and Cocaine-Like Subjective Effects of Uptake Inhibitors. Mol Pharmacol 2007; 73:813-23. [DOI: 10.1124/mol.107.039800] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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Rothman RB, Baumann M, Prisinzano TE, Newman AH. Dopamine transport inhibitors based on GBR12909 and benztropine as potential medications to treat cocaine addiction. Biochem Pharmacol 2007; 75:2-16. [PMID: 17897630 PMCID: PMC2225585 DOI: 10.1016/j.bcp.2007.08.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2007] [Revised: 08/02/2007] [Accepted: 08/06/2007] [Indexed: 12/20/2022]
Abstract
The discovery and development of medications to treat addiction and notably, cocaine addiction, have been frustrated by both the complexity of the disorder and the lack of target validation in human subjects. The dopamine transporter has historically been a primary target for cocaine abuse medication development, but addictive liability and other confounds of such inhibitors of dopamine uptake have limited clinical evaluation and validation. Herein we describe efforts to develop analogues of the dopamine uptake inhibitors GBR 12909 and benztropine that show promising profiles in animal models of cocaine abuse that contrast to that of cocaine. Their unique pharmacological profiles have provided important insights into the reinforcing actions of cocaine and we propose that clinical investigation of novel dopamine uptake inhibitors will facilitate the discovery of cocaine-abuse medications.
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Affiliation(s)
- Richard B. Rothman
- Clinical Psychopharmacology, National Institute on Drug Abuse – Intramural Research Program, National Institutes of Health, Baltimore, Maryland
| | - Michael Baumann
- Clinical Psychopharmacology, National Institute on Drug Abuse – Intramural Research Program, National Institutes of Health, Baltimore, Maryland
| | | | - Amy Hauck Newman
- Medicinal Chemistry Sections, National Institute on Drug Abuse – Intramural Research Program, National Institutes of Health, Baltimore, Maryland
- *Corresponding Author Amy Hauck Newman, Ph.D. Medicinal Chemistry Section, NIDA-IRP, NIH, 333 Cassell Dr. Baltimore, MD 21224, 410-550-6568 X114,
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Othman AA, Newman AH, Eddington ND. Applicability of the dopamine and rate hypotheses in explaining the differences in behavioral pharmacology of the chloro-benztropine analogs: studies conducted using intracerebral microdialysis and population pharmacodynamic modeling. J Pharmacol Exp Ther 2007; 322:760-9. [PMID: 17519385 DOI: 10.1124/jpet.107.123315] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous studies indicated that the chloro-benztropine analogs differed significantly in their cocaine-like activity, which was not expected based on the similarity in their in vitro binding affinity and functional potency at the dopamine transporter (DAT). The present study was designed to extend the understanding of the involvement of both pharmacokinetic and pharmacodynamic factors in mediating the behavioral differences among these analogs. The pharmacokinetics of 3'-chloro-3alpha-(diphenylmethoxy)tropane (3'-Cl BZT), the analog showing a cocaine-like behavioral profile in rodents, was compared with previously reported pharmacokinetic characteristics of cocaine and 4',4''-dichloro-3alpha-(diphenylmethoxy)tropane (4',4''-diCl BZT), an analog totally devoid of cocaine-like actions. Microdialysis studies in rats were conducted to determine whether 3'-Cl and 4',4''-diCl BZT differed significantly in their effect on nucleus accumbens extracellular dopamine levels, with cocaine serving as a reference. A mechanistic model based on DAT association/dissociation kinetics was used to describe the time delay between the plasma concentrations of the chloro-analogs and their dopaminergic effects. 3'-Cl BZT had plasma elimination half-life of 1.9 h versus 0.5 and 21.1 h for cocaine and 4',4''-diCl BZT, respectively. 4',4''-diCl BZT increased the DA levels at a slower rate and to a significantly lower extent relative to 3'-Cl BZT that were, in turn, lower than cocaine. The duration of dopamine elevation was as follows: 4',4''-diCl BZT > 3'-Cl BZT > cocaine. The model indicated faster association and dissociation with DAT for 3'-Cl BZT relative to 4',4''-diCl BZT. The present results indicate that behavioral differences among the chloro-analogs may be explainable based on both the dopamine and rate hypotheses of drug abuse.
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Affiliation(s)
- Ahmed A Othman
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, Baltimore, MD 21201, USA.
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Kulkarni SS, Kopajtic TA, Katz JL, Newman AH. Comparative structure-activity relationships of benztropine analogues at the dopamine transporter and histamine H(1) receptors. Bioorg Med Chem 2006; 14:3625-34. [PMID: 16460947 PMCID: PMC1555624 DOI: 10.1016/j.bmc.2006.01.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2005] [Revised: 01/10/2006] [Accepted: 01/10/2006] [Indexed: 11/16/2022]
Abstract
Benztropine (BZT) and its analogues inhibit dopamine uptake and bind with moderate to high affinity to the dopamine transporter (DAT). However, many of these compounds, in contrast to other monoamine uptake inhibitors, lack cocaine-like behavioral effects and fail to potentiate the effects of cocaine. The BZT analogues also exhibit varied binding affinities for muscarinic M(1) and histamine H(1) receptors. In this study, a comparative analysis was conducted of pharmacophoric features with respect to the activities of BZT analogues at the DAT and at the histamine H(1) receptor. The BZT analogues showed a wide range of histamine H(1) receptor (K(i)=16-37,600 nM) and DAT (K(i)=8.5-6370 nM) binding affinities. A stereoselective histamine H(1)-antagonist pharmacophore, using a five-point superimposition of classical antagonists on the template, cyproheptadine, was developed. A series of superimpositions and comparisons were performed with various analogues of BZT. In general, smaller substituents were well tolerated on the aromatic rings of the diphenyl methoxy group for both the DAT and H(1) receptor, however, for the H(1) receptor, substitution at only one of the aromatic rings was preferred. The substituents at the 2- and N-positions of the tropane ring were preferred for DAT, however, these groups seem to overlap receptor essential regions in the histamine H(1) receptor. Molecular models at the DAT and the histamine H(1) receptor provide further insight into the structural requirements for binding affinity and selectivity that can be implemented in future drug design.
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Affiliation(s)
- Santosh S. Kulkarni
- Medicinal Chemistry, Intramural Research Program, National Institute on Drug Abuse, NIH, 5500, Nathan Shock Drive, Baltimore, MD-21224 USA
| | - Theresa A. Kopajtic
- Psychobiology Sections, Intramural Research Program, National Institute on Drug Abuse, NIH, 5500, Nathan Shock Drive, Baltimore, MD-21224 USA
| | - Jonathan L. Katz
- Psychobiology Sections, Intramural Research Program, National Institute on Drug Abuse, NIH, 5500, Nathan Shock Drive, Baltimore, MD-21224 USA
| | - Amy Hauck Newman
- Medicinal Chemistry, Intramural Research Program, National Institute on Drug Abuse, NIH, 5500, Nathan Shock Drive, Baltimore, MD-21224 USA
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