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Soto PL, Hiranita T. Effects of benztropine analogs on delay discounting in rats. Psychopharmacology (Berl) 2020; 237:3783-3794. [PMID: 32964243 PMCID: PMC7686108 DOI: 10.1007/s00213-020-05655-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Accepted: 08/31/2020] [Indexed: 10/23/2022]
Abstract
RATIONALE Methylphenidate and d-amphetamine, medications used for treatment of attention deficit hyperactivity disorder (ADHD), are used recreationally and self-administered by laboratory animals. Benztropine (BZT) analogs, like those medications, increase synaptic dopamine levels but are less effective in maintaining self-administration, suggesting clinical utility with less abuse liability. OBJECTIVES The current study was designed to evaluate potential therapeutic effects of BZT analogs related to ADHD. METHODS Rats responded under a delay-discounting procedure in which responses on one lever produced immediate delivery of a single food pellet and alternative responses produced four food pellets either immediately or with various temporal delays, with those delays arranged in ascending or random orders in different groups of rats. Selection of the smaller more immediate reinforcer has been suggested as an aspect of "impulsivity," a trait with suggested involvement in ADHD. Other rats were studied under fixed-interval (FI) 300-s schedules to assess drug effects on behavior under temporal control. RESULTS d-Amphetamine, methylphenidate, and the BZT analog AHN 1-055, but not AHN 2-005 or JHW 007, increased selection of the large, delayed reinforcer with either arrangement of delays. All drugs changed the temporal distribution of responses within the FI from one with responses concentrated at the end to a more uniform distribution. Changes in the temporal distribution of FI responding occurred with drugs that did not affect discounting suggesting that discounting does not arise directly from the same temporal control processes controlling FI responding. CONCLUSIONS AHN 1-055 may be of clinical utility in the treatment of ADHD.
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Affiliation(s)
- Paul L Soto
- Department of Psychology, Louisiana State University, Baton Rouge, LA, 70803, USA.
| | - Takato Hiranita
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, USA
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Mikelman SR, Guptaroy B, Schmitt KC, Jones KT, Zhen J, Reith MEA, Gnegy ME. Tamoxifen Directly Interacts with the Dopamine Transporter. J Pharmacol Exp Ther 2018; 367:119-128. [PMID: 30108161 PMCID: PMC7250473 DOI: 10.1124/jpet.118.248179] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 07/26/2018] [Indexed: 11/22/2022] Open
Abstract
The selective estrogen receptor modulator tamoxifen increases extracellular dopamine in vivo and acts as a neuroprotectant in models of dopamine neurotoxicity. We investigated the effect of tamoxifen on dopamine transporter (DAT)-mediated dopamine uptake, dopamine efflux, and [3H]WIN 35,428 [(-)-2-β-carbomethoxy-3-β-(4-fluorophenyl)tropane] binding in rat striatal tissue. Tamoxifen dose-dependently blocked dopamine uptake (54% reduction at 10 μM) and amphetamine-stimulated efflux (59% reduction at 10 μM) in synaptosomes. It also produced a small but significant reduction in [3H]WIN 35,428 binding in striatal membranes, indicating a weak interaction with the substrate binding site in the DAT. Biotinylation and cysteine accessibility studies indicated that tamoxifen stabilizes the outward-facing conformation of the DAT in a cocaine-like manner and does not affect surface expression of the DAT. Additional studies with mutant DAT constructs D476A and I159A suggested a direct interaction between tamoxifen and a secondary substrate binding site of the transporter. Locomotor studies revealed that tamoxifen attenuates amphetamine-stimulated hyperactivity in rats but has no depressant or stimulant activity in the absence of amphetamine. These results suggest a complex mechanism of action for tamoxifen as a regulator of the DAT. Due to its effectiveness against amphetamine actions and its central nervous system permeant activity, the tamoxifen structure represents an excellent starting point for a structure-based drug-design program to develop a pharmacological therapeutic for psychostimulant abuse.
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Affiliation(s)
- Sarah R Mikelman
- Gnegy Laboratory, Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, Michigan (S.R.M., B.G., M.E.G.); and Reith Laboratory, Department of Psychiatry, University of New York School of Medicine, New York, New York (K.C.S., K.T.J., J.Z., M.E.A.R.)
| | - Bipasha Guptaroy
- Gnegy Laboratory, Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, Michigan (S.R.M., B.G., M.E.G.); and Reith Laboratory, Department of Psychiatry, University of New York School of Medicine, New York, New York (K.C.S., K.T.J., J.Z., M.E.A.R.)
| | - Kyle C Schmitt
- Gnegy Laboratory, Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, Michigan (S.R.M., B.G., M.E.G.); and Reith Laboratory, Department of Psychiatry, University of New York School of Medicine, New York, New York (K.C.S., K.T.J., J.Z., M.E.A.R.)
| | - Kymry T Jones
- Gnegy Laboratory, Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, Michigan (S.R.M., B.G., M.E.G.); and Reith Laboratory, Department of Psychiatry, University of New York School of Medicine, New York, New York (K.C.S., K.T.J., J.Z., M.E.A.R.)
| | - Juan Zhen
- Gnegy Laboratory, Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, Michigan (S.R.M., B.G., M.E.G.); and Reith Laboratory, Department of Psychiatry, University of New York School of Medicine, New York, New York (K.C.S., K.T.J., J.Z., M.E.A.R.)
| | - Maarten E A Reith
- Gnegy Laboratory, Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, Michigan (S.R.M., B.G., M.E.G.); and Reith Laboratory, Department of Psychiatry, University of New York School of Medicine, New York, New York (K.C.S., K.T.J., J.Z., M.E.A.R.)
| | - Margaret E Gnegy
- Gnegy Laboratory, Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, Michigan (S.R.M., B.G., M.E.G.); and Reith Laboratory, Department of Psychiatry, University of New York School of Medicine, New York, New York (K.C.S., K.T.J., J.Z., M.E.A.R.)
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Hong WC, Wasko MJ, Wilkinson DS, Hiranita T, Li L, Hayashi S, Snell DB, Madura JD, Surratt CK, Katz JL. Dopamine Transporter Dynamics of N-Substituted Benztropine Analogs with Atypical Behavioral Effects. J Pharmacol Exp Ther 2018; 366:527-540. [PMID: 29945932 DOI: 10.1124/jpet.118.250498] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 06/22/2018] [Indexed: 01/07/2023] Open
Abstract
Atypical dopamine transporter (DAT) inhibitors, despite high DAT affinity, do not produce the psychomotor stimulant and abuse profile of standard DAT inhibitors such as cocaine. Proposed contributing features for those differences include off-target actions, slow onsets of action, and ligand bias regarding DAT conformation. Several 3α-(4',4''-difluoro-diphenylmethoxy)tropanes were examined, including those with the following substitutions: N-(indole-3''-ethyl)- (GA1-69), N-(R)-2''-amino-3''-methyl-n-butyl- (GA2-50), N-2''aminoethyl- (GA2-99), and N-(cyclopropylmethyl)- (JHW013). These compounds were previously reported to have rapid onset of behavioral effects and were presently evaluated pharmacologically alone or in combination with cocaine. DAT conformational mode was assessed by substituted-cysteine accessibility and molecular dynamics (MD) simulations. As determined by substituted-cysteine alkylation, all BZT analogs except GA2-99 showed bias for a cytoplasmic-facing DAT conformation, whereas cocaine stabilized the extracellular-facing conformation. MD simulations suggested that several analog-DAT complexes formed stable R85-D476 "outer gate" bonds that close the DAT to extracellular space. GA2-99 diverged from this pattern, yet had effects similar to those of other atypical DAT inhibitors. Apparent DAT association rates of the BZT analogs in vivo were slower than that for cocaine. None of the compounds was self-administered or stimulated locomotion, and each blocked those effects of cocaine. The present findings provide more detail on ligand-induced DAT conformations and indicate that aspects of DAT conformation other than "open" versus "closed" may facilitate predictions of the actions of DAT inhibitors and may promote rational design of potential treatments for psychomotor-stimulant abuse.
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Affiliation(s)
- Weimin C Hong
- Department of Pharmaceutical Sciences, Butler University, Indianapolis, Indiana (W.C.H.); Division of Pharmaceutical Sciences (M.J.W., C.K.S.) and Department of Chemistry and Biochemistry (J.D.M.), Duquesne University, Pittsburgh; and Molecular Neuropsychiatry Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland (D.S.W., T.H., L.L., S.H., D.B.S., J.L.K.)
| | - Michael J Wasko
- Department of Pharmaceutical Sciences, Butler University, Indianapolis, Indiana (W.C.H.); Division of Pharmaceutical Sciences (M.J.W., C.K.S.) and Department of Chemistry and Biochemistry (J.D.M.), Duquesne University, Pittsburgh; and Molecular Neuropsychiatry Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland (D.S.W., T.H., L.L., S.H., D.B.S., J.L.K.)
| | - Derek S Wilkinson
- Department of Pharmaceutical Sciences, Butler University, Indianapolis, Indiana (W.C.H.); Division of Pharmaceutical Sciences (M.J.W., C.K.S.) and Department of Chemistry and Biochemistry (J.D.M.), Duquesne University, Pittsburgh; and Molecular Neuropsychiatry Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland (D.S.W., T.H., L.L., S.H., D.B.S., J.L.K.)
| | - Takato Hiranita
- Department of Pharmaceutical Sciences, Butler University, Indianapolis, Indiana (W.C.H.); Division of Pharmaceutical Sciences (M.J.W., C.K.S.) and Department of Chemistry and Biochemistry (J.D.M.), Duquesne University, Pittsburgh; and Molecular Neuropsychiatry Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland (D.S.W., T.H., L.L., S.H., D.B.S., J.L.K.)
| | - Libin Li
- Department of Pharmaceutical Sciences, Butler University, Indianapolis, Indiana (W.C.H.); Division of Pharmaceutical Sciences (M.J.W., C.K.S.) and Department of Chemistry and Biochemistry (J.D.M.), Duquesne University, Pittsburgh; and Molecular Neuropsychiatry Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland (D.S.W., T.H., L.L., S.H., D.B.S., J.L.K.)
| | - Shuichiro Hayashi
- Department of Pharmaceutical Sciences, Butler University, Indianapolis, Indiana (W.C.H.); Division of Pharmaceutical Sciences (M.J.W., C.K.S.) and Department of Chemistry and Biochemistry (J.D.M.), Duquesne University, Pittsburgh; and Molecular Neuropsychiatry Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland (D.S.W., T.H., L.L., S.H., D.B.S., J.L.K.)
| | - David B Snell
- Department of Pharmaceutical Sciences, Butler University, Indianapolis, Indiana (W.C.H.); Division of Pharmaceutical Sciences (M.J.W., C.K.S.) and Department of Chemistry and Biochemistry (J.D.M.), Duquesne University, Pittsburgh; and Molecular Neuropsychiatry Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland (D.S.W., T.H., L.L., S.H., D.B.S., J.L.K.)
| | - Jeffry D Madura
- Department of Pharmaceutical Sciences, Butler University, Indianapolis, Indiana (W.C.H.); Division of Pharmaceutical Sciences (M.J.W., C.K.S.) and Department of Chemistry and Biochemistry (J.D.M.), Duquesne University, Pittsburgh; and Molecular Neuropsychiatry Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland (D.S.W., T.H., L.L., S.H., D.B.S., J.L.K.)
| | - Christopher K Surratt
- Department of Pharmaceutical Sciences, Butler University, Indianapolis, Indiana (W.C.H.); Division of Pharmaceutical Sciences (M.J.W., C.K.S.) and Department of Chemistry and Biochemistry (J.D.M.), Duquesne University, Pittsburgh; and Molecular Neuropsychiatry Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland (D.S.W., T.H., L.L., S.H., D.B.S., J.L.K.)
| | - Jonathan L Katz
- Department of Pharmaceutical Sciences, Butler University, Indianapolis, Indiana (W.C.H.); Division of Pharmaceutical Sciences (M.J.W., C.K.S.) and Department of Chemistry and Biochemistry (J.D.M.), Duquesne University, Pittsburgh; and Molecular Neuropsychiatry Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland (D.S.W., T.H., L.L., S.H., D.B.S., J.L.K.)
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Dassanayake AF, Canales JJ. Replacement treatment during extinction training with the atypical dopamine uptake inhibitor, JHW-007, reduces relapse to methamphetamine seeking. Neurosci Lett 2018; 671:88-92. [PMID: 29452175 DOI: 10.1016/j.neulet.2018.02.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 01/26/2018] [Accepted: 02/12/2018] [Indexed: 12/29/2022]
Abstract
There are currently no approved medications to effectively counteract the effects of methamphetamine (METH), reduce its abuse and prolong abstinence from it. Data accumulated in recent years have shown that a range of N-substituted benztropine (BZT) analogues possesses psychopharmacological features consistent with those of a potential replacement or "substitute" treatment for stimulant addiction. On the other hand, the evidence that antidepressant therapy may effectively prevent relapse to stimulant seeking is controversial. Here, we compared in rats the ability of the BZT analogue and high affinity dopamine (DA) reuptake inhibitor, JHW-007, and the antidepressant, trazodone, administered during extinction sessions after chronic METH self-administration, to alter METH-primed reinstatement of drug seeking. The data showed that trazodone produced paradoxical effects on lever pressing during extinction of METH self-administration, decreasing active, but increasing inactive, lever pressing. JHW-007 did not have any observable effects on extinction training. Importantly, JHW-007 significantly attenuated METH-primed reinstatement, whereas trazodone enhanced it. These findings lend support to the candidacy of selective DA uptake blockers, such as JHW-007, as potential treatments for METH addiction, but not to the use of antidepressant medication as a single therapeutic approach for relapse prevention.
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Affiliation(s)
- Ashlea F Dassanayake
- Division of Psychology, School of Medicine, University of Tasmania, Private Bag 30, Hobart, TAS, 7001, Australia
| | - Juan J Canales
- Division of Psychology, School of Medicine, University of Tasmania, Private Bag 30, Hobart, TAS, 7001, Australia.
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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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Pei Y, Asif-Malik A, Hoener M, Canales JJ. A partial trace amine-associated receptor 1 agonist exhibits properties consistent with a methamphetamine substitution treatment. Addict Biol 2017; 22:1246-1256. [PMID: 27193165 DOI: 10.1111/adb.12410] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 04/04/2016] [Accepted: 04/25/2016] [Indexed: 12/25/2022]
Abstract
Recent evidence suggests that the trace amine-associated receptor 1 (TAAR1) plays a pivotal role in the regulation of dopamine (DA) transmission and psychostimulant action. Several selective TAAR1 agonists have previously shown efficacy in models of cocaine addiction. However, the effects of TAAR1 activation on methamphetamine (METH)-induced behaviours are less well understood, as indeed are the underlying neurochemical mechanisms mediating potential interactions between TAAR1 and METH. Here, in a progressive ratio schedule of reinforcement the partial TAAR1 agonist, RO5263397, reduced the break-point for METH self-administration, while significantly increasing responding maintained by food reward. Following self-administration and extinction training, RO5263397 completely blocked METH-primed reinstatement of METH seeking. Moreover, when used as a substitute, unlike a low dose of METH, which sustained vigorous responding when substituting for the training dose of METH, RO5263397 was not self-administered at any dose, thus exhibiting no apparent abuse liability. Fast-scan cyclic voltammetry experiments showed that RO5263397 prevented METH-induced DA overflow in slices of the nucleus accumbens, while having no effect on DA transmission in its own right. Collectively, the present observations demonstrate that partial TAAR1 activation decreases the motivation to self-administer METH, blocks METH-primed reinstatement of METH seeking and prevents METH-induced DA elevations in the nucleus accumbens, and strongly support the candidacy of TAAR1-based medications as potential substitute treatment in METH addiction.
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Affiliation(s)
- Yue Pei
- Department of Neuroscience, Psychology and Behaviour; University of Leicester; Leicester UK
| | - Aman Asif-Malik
- Department of Neuroscience, Psychology and Behaviour; University of Leicester; Leicester UK
| | - Marius Hoener
- Neuroscience, Ophthalmology and Rare Diseases Discovery & Translational Area; pRED, Roche Innovation Center Basel; Basel Switzerland
| | - Juan J. Canales
- Department of Neuroscience, Psychology and Behaviour; University of Leicester; Leicester UK
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Hiranita T, Hong WC, Kopajtic T, Katz JL. σ Receptor Effects of N-Substituted Benztropine Analogs: Implications for Antagonism of Cocaine Self-Administration. J Pharmacol Exp Ther 2017; 362:2-13. [PMID: 28442581 PMCID: PMC5454590 DOI: 10.1124/jpet.117.241109] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 04/20/2017] [Indexed: 11/22/2022] Open
Abstract
Several N-substituted benztropine (BZT) analogs are atypical dopamine transport inhibitors as they have affinity for the dopamine transporter (DAT) but have minimal cocaine-like pharmacologic effects and can block numerous effects of cocaine, including its self-administration. Among these compounds, N-methyl (AHN1-055), N-allyl (AHN2-005), and N-butyl (JHW007) analogs of 3α-[bis(4'-fluorophenyl)methoxy]-tropane were more potent in antagonizing self-administration of cocaine and d-methamphetamine than in decreasing food-maintained responding. The antagonism of cocaine self-administration (0.03-1.0 mg/kg per injection) with the above BZT analogs was reproduced in the present study. Further, the stimulant-antagonist effects resembled previously reported effects of pretreatments with combinations of standard DAT inhibitors and σ1-receptor (σ1R) antagonists. Therefore, the present study examined binding of the BZT analogs to σRs, as well as their in vivo σR antagonist effects. Each of the BZT analogs displaced radiolabeled σR ligands with nanomolar affinity. Further, self-administration of the σR agonist DTG (0.1-3.2 mg/kg/injection) was dose dependently blocked by AHN2-005 and JHW007 but potentiated by AHN1-055. In contrast, none of the BZT analogs that were active against DTG self-administration was active against the self-administration of agonists at dopamine D1-like [R(+)-SKF 81297, (±)-SKF 82958 (0.00032-0.01 mg/kg per injection each)], D2-like [R(-)-NPA (0.0001-0.0032 mg/kg per injection), (-)-quinpirole (0.0032-0.1 mg/kg per injection)], or μ-opioid (remifentanil, 0.0001-0.0032 mg/kg per injection) receptors. The present results indicate that behavioral antagonist effects of the N-substituted BZT analogs are specific for abused drugs acting at the DAT and further suggest that σR antagonism contributes to those actions.
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Affiliation(s)
- Takato Hiranita
- Psychobiology Section, Molecular Neuropsychiatry Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health (T.H., T.K., J.L.K.), and Department of Pharmaceutical Sciences, Butler University (W.C.H.), Indianapolis, Indiana
| | - Weimin C Hong
- Psychobiology Section, Molecular Neuropsychiatry Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health (T.H., T.K., J.L.K.), and Department of Pharmaceutical Sciences, Butler University (W.C.H.), Indianapolis, Indiana
| | - Theresa Kopajtic
- Psychobiology Section, Molecular Neuropsychiatry Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health (T.H., T.K., J.L.K.), and Department of Pharmaceutical Sciences, Butler University (W.C.H.), Indianapolis, Indiana
| | - Jonathan L Katz
- Psychobiology Section, Molecular Neuropsychiatry Research Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health (T.H., T.K., J.L.K.), and Department of Pharmaceutical Sciences, Butler University (W.C.H.), Indianapolis, Indiana
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Further delineation between typical and atypical dopamine uptake inhibitors: effects on food-maintained behavior and food consumption. Behav Pharmacol 2016; 28:74-82. [PMID: 27926573 DOI: 10.1097/fbp.0000000000000278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The present studies compared the acute effects of benztropine analogs (4-Cl-BZT, JHW 007, AHN 1-055), which are atypical dopamine uptake inhibitors, with those of the standard dopamine uptake inhibitors GBR 12909 and cocaine, on the reinforcing efficacy of food and food intake in male Sprague-Dawley rats. Repeated drug effects of JHW 007 on food intake were also determined. The number of ratios completed under a progressive-ratio schedule of food delivery was used as an index of reinforcing efficacy. Food intake was determined by measuring powdered laboratory-chow consumption during daily 40 min food-availability time periods. Under the progressive-ratio schedule, cocaine and GBR 12909 dose-dependently increased the number of ratios completed. JHW 007 decreased ratios completed, whereas neither 4-Cl-BZT nor AHN 1-055 increased ratios completed with a magnitude that approximated any of the increases produced by cocaine or GBR 12909. Acute administration of each drug dose-dependently decreased food intake; however, the benztropine analogs were more potent than cocaine and GBR 12909. A reduction in food intake emerged after repeated administration of a low dose of JHW 007. Future studies that compare JHW 007 with standard anorectic drugs (e.g. phentermine) and continue investigation of the repeated drug effects under similar experimental procedures are clearly warranted.
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Golovko AI, Bonitenko EY, Ivanov MB, Barinov VA, Zatsepin EP. The neurochemical bases of the pharmacological activity of ligands of monoamine-transport systems. NEUROCHEM J+ 2016. [DOI: 10.1134/s1819712416030065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Pei Y, Asif-Malik A, Canales JJ. Trace Amines and the Trace Amine-Associated Receptor 1: Pharmacology, Neurochemistry, and Clinical Implications. Front Neurosci 2016; 10:148. [PMID: 27092049 PMCID: PMC4820462 DOI: 10.3389/fnins.2016.00148] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 03/21/2016] [Indexed: 01/30/2023] Open
Abstract
Biogenic amines are a collection of endogenous molecules that play pivotal roles as neurotransmitters and hormones. In addition to the "classical" biogenic amines resulting from decarboxylation of aromatic acids, including dopamine (DA), norepinephrine, epinephrine, serotonin (5-HT), and histamine, other biogenic amines, present at much lower concentrations in the central nervous system (CNS), and hence referred to as "trace" amines (TAs), are now recognized to play significant neurophysiological and behavioral functions. At the turn of the century, the discovery of the trace amine-associated receptor 1 (TAAR1), a phylogenetically conserved G protein-coupled receptor that is responsive to both TAs, such as β-phenylethylamine, octopamine, and tyramine, and structurally-related amphetamines, unveiled mechanisms of action for TAs other than interference with aminergic pathways, laying the foundations for deciphering the functional significance of TAs and its mammalian CNS receptor, TAAR1. Although, its molecular interactions and downstream targets have not been fully elucidated, TAAR1 activation triggers accumulation of intracellular cAMP, modulates PKA and PKC signaling and interferes with the β-arrestin2-dependent pathway via G protein-independent mechanisms. TAAR1 is uniquely positioned to exert direct control over DA and 5-HT neuronal firing and release, which has profound implications for understanding the pathophysiology of, and therefore designing more efficacious therapeutic interventions for, a range of neuropsychiatric disorders that involve aminergic dysregulation, including Parkinson's disease, schizophrenia, mood disorders, and addiction. Indeed, the recent development of novel pharmacological tools targeting TAAR1 has uncovered the remarkable potential of TAAR1-based medications as new generation pharmacotherapies in neuropsychiatry. This review summarizes recent developments in the study of TAs and TAAR1, their intricate neurochemistry and pharmacology, and their relevance for neurodegenerative and neuropsychiatric disease.
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Affiliation(s)
| | | | - Juan J. Canales
- Department of Neuroscience, Psychology and Behaviour, University of LeicesterLeicester, UK
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Selective activation of the trace amine-associated receptor 1 decreases cocaine's reinforcing efficacy and prevents cocaine-induced changes in brain reward thresholds. Prog Neuropsychopharmacol Biol Psychiatry 2015; 63:70-5. [PMID: 26048337 DOI: 10.1016/j.pnpbp.2015.05.014] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 05/26/2015] [Accepted: 05/26/2015] [Indexed: 01/09/2023]
Abstract
The newly discovered trace amine-associated receptor 1 (TAAR1) has emerged as a promising target for medication development in stimulant addiction due to its ability to regulate dopamine (DA) function and modulate stimulants' effects. Recent findings indicate that TAAR1 activation blocks some of the abuse-related physiological and behavioral effects of cocaine. However, findings from existing self-administration studies are inconclusive due to the very limited range of cocaine unit doses tested. Here, in order to shed light on the influence of TAAR1 on cocaine's reward and reinforcement, we studied the effects of partial and full activation of TAAR1on (1) the dose-response curve for cocaine self-administration and (2) cocaine-induced changes in intracranial self-stimulation (ICSS). In the first experiment, we examined the effects of the selective full and partial TAAR1 agonists, RO5256390 and RO5203648, on self-administration of five unit-injection doses of cocaine (0.03, 0.1, 0.2, 0.45, and 1mg/kg/infusion). Both agonists induced dose-dependent downward shifts in the cocaine dose-response curve, indicating that both partial and full TAAR1 activation decrease cocaine, reinforcing efficacy. In the second experiment, RO5256390 and the partial agonist, RO5263397, dose-dependently prevented cocaine-induced lowering of ICSS thresholds. Taken together, these data demonstrated that TAAR1 stimulation effectively suppresses the rewarding and reinforcing effects of cocaine in self-administration and ICSS models, supporting the candidacy of TAAR1 as a drug discovery target for cocaine addiction.
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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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Hamilton J, Lee J, Canales JJ. Chronic unilateral stimulation of the nucleus accumbens at high or low frequencies attenuates relapse to cocaine seeking in an animal model. Brain Stimul 2014; 8:57-63. [PMID: 25457212 DOI: 10.1016/j.brs.2014.09.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 09/23/2014] [Accepted: 09/28/2014] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Deep brain stimulation (DBS), a form of neurosurgical intervention that is used to modulate the electrophysiological activity of specific brain areas, has emerged as a form of therapy for severe cases of treatment-refractory addiction. OBJECTIVE/HYPOTHESIS Recent research suggests that the nucleus accumbens (NAC) is a promising target area for DBS in addiction. The current experiments were designed to determine optimal parameters of stimulation and long-term efficacy of NAC DBS in an animal model of cocaine addiction. METHODS Rats were implanted with a stimulating electrode in the right NAC and exposed to chronic cocaine self-administration (0.5 mg/kg/infusion). Rats underwent drug seeking tests by exposing them to the self-administration context paired with cocaine challenge (5 mg/kg i.p.) on days 1, 15 and 30 after withdrawal from cocaine self-administration. Low-frequency (LF, 20 Hz) or high-frequency (HF, 160 Hz) DBS was applied for 30 min daily for 14 consecutive days starting one day after drug withdrawal. RESULTS Rats exhibited robust drug-seeking 1, 15 and 30 days after withdrawal from cocaine self-administration, with responding being highest on day 15. Both LF and HF attenuated cocaine seeking on day 15 post-withdrawal by 36 and 48%, respectively. Both forms of stimulation were ineffective on the tests conducted on days 1 and 30. CONCLUSION The present data showed that unilateral DBS of the NAC effectively attenuated cocaine relapse after 15 days of drug withdrawal, with therapeutic-like effects seemingly diminishing after DBS discontinuation. This evidence provides support for DBS as a promising intervention in intractable cases of stimulant addiction.
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Affiliation(s)
- J Hamilton
- Department of Psychology, University of Canterbury, Christchurch, New Zealand
| | - J Lee
- Department of Psychology, University of Canterbury, Christchurch, New Zealand
| | - J J Canales
- School of Psychology, University of Leicester, Leicester, United Kingdom.
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Pei Y, Lee J, Leo D, Gainetdinov RR, Hoener MC, Canales JJ. Activation of the trace amine-associated receptor 1 prevents relapse to cocaine seeking. Neuropsychopharmacology 2014; 39:2299-308. [PMID: 24722355 PMCID: PMC4138750 DOI: 10.1038/npp.2014.88] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 03/22/2014] [Accepted: 04/04/2014] [Indexed: 02/08/2023]
Abstract
The trace amine-associated receptor 1 (TAAR1) has emerged as a promising target for medication development in addiction because of its ability to regulate dopamine (DA) transmission. We tested in rats the efficacy of RO5203648 and RO5256390, partial and full TAAR1 agonists, respectively, in models of cocaine relapse. Using a model of context-induced relapse, both RO5203648 and RO5256390 dose-dependently suppressed cocaine seeking after a 2-week period of withdrawal from chronic cocaine self-administration. In a model of extinction-reinstatement, RO5203648 completely inhibited cocaine-primed reinstatement of cocaine seeking. At doses that effectively suppressed cocaine seeking neither RO5203648 nor RO5256390 altered responding maintained by a natural reward. Moreover, fast scan cyclic voltammetry data showed that RO5203648 prevented cocaine-induced DA overflow in the nucleus accumbens without altering DA half-life, suggesting that the partial TAAR1 agonist attenuated cocaine-stimulated DA overflow by mechanisms other than direct interference with DA uptake. Collectively, these data provide strong evidence in support of TAAR1 as a neuropharmacological target for the treatment of cocaine addiction.
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Affiliation(s)
- Yui Pei
- Behavioural Neuroscience, Department of Psychology, University of Canterbury, Christchurch, New Zealand
| | - Jungah Lee
- Behavioural Neuroscience, Department of Psychology, University of Canterbury, Christchurch, New Zealand
| | - Damiana Leo
- Department of Neuroscience and Brain Technologies, Italian Institute of Technology, Genoa, Italy
| | - Raul R Gainetdinov
- Department of Neuroscience and Brain Technologies, Italian Institute of Technology, Genoa, Italy,Skolkovo Institute of Science and Technology, Skolkovo, Russia,Faculty of Biology and Soil Science, St Petersburg State University, St Petersburg, Russia
| | - Marius C Hoener
- Neuroscience Research, Pharmaceuticals Division, F Hoffmann-La Roche, Basel, Switzerland
| | - Juan J Canales
- Behavioural Neuroscience, Department of Psychology, University of Canterbury, Christchurch, New Zealand,Behavioural Neuroscience, Department of Psychology, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand, Tel: +64 3 364 2987 Ext. 7005 (office) 7303 (lab), Fax: +64 3 364 2181, E-mail:
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Ferragud A, Velázquez-Sánchez C, Canales JJ. Modulation of methamphetamine's locomotor stimulation and self-administration by JHW 007, an atypical dopamine reuptake blocker. Eur J Pharmacol 2014; 731:73-9. [PMID: 24675149 DOI: 10.1016/j.ejphar.2014.03.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Revised: 02/20/2014] [Accepted: 03/17/2014] [Indexed: 11/28/2022]
Abstract
JHW 007 [N-(n-butil)-3α-[bis(4'-fluorophenil)methoxi]-tropane] belongs to the family of N-substituted benztropine (BZT) analogs, atypical dopamine transporter (DAT) blockers that are able to strongly modulate cocaine- and amphetamine-related behavior. In the present study, we tested in rats the ability of JHW 007 to alter the stimulant and reinforcing properties of methamphetamine (METH) using locomotor activity, fixed ratio and progressive ratio (PR) self-administration tests. The results showed that JHW 007 attenuated METH-induced locomotor stimulation in a dose-dependent manner and had no stimulant effects when administered alone. The BZT analog, given as a pre-treatment, attenuated METH self-administration without affecting responding for sucrose. In the PR tests JHW 007 produced an increase of the breaking point achieved for both METH- and sucrose self-administration, suggesting that the ability of the BZT analog to reduce self-administration may be linked to its ability to enhance the reinforcing properties of METH. Taken together, these data suggest that DAT inhibition with a high affinity blocker such as JHW 007 can exert differential effects on METH-associated behaviors, reducing METH-induced motor stimulation but augmenting METH׳s reinforcing effects.
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Affiliation(s)
- A Ferragud
- Department of Psychology, University of Canterbury, Christchurch, New Zealand
| | - C Velázquez-Sánchez
- Department of Psychology, University of Canterbury, Christchurch, New Zealand
| | - J J Canales
- Department of Psychology, University of Canterbury, Christchurch, New Zealand.
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Canales JJ, Ferrer-Donato A. Prenatal Exposure to Alcohol and 3,4-Methylenedioxymethamphetamine (Ecstasy) Alters Adult Hippocampal Neurogenesis and Causes Enduring Memory Deficits. Dev Neurosci 2014; 36:10-7. [DOI: 10.1159/000356820] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 10/25/2013] [Indexed: 11/19/2022] Open
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Hiranita T, Kohut SJ, Soto PL, Tanda G, Kopajtic TA, Katz JL. Preclinical efficacy of N-substituted benztropine analogs as antagonists of methamphetamine self-administration in rats. J Pharmacol Exp Ther 2014; 348:174-91. [PMID: 24194527 PMCID: PMC3868882 DOI: 10.1124/jpet.113.208264] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 11/04/2013] [Indexed: 01/16/2023] Open
Abstract
Atypical dopamine-uptake inhibitors have low abuse potential and may serve as leads for development of cocaine-abuse treatments. Among them, the benztropine (BZT) derivatives, N-butyl (JHW007), N-allyl (AHN2-005), and N-methyl (AHN1-055) analogs of 3α-[bis(4'-fluorophenyl)methoxy]-tropane dose-dependently decreased cocaine self-administration without effects on food-maintained responding. Our study examined selectivity by assessing their effects on self-administration of other drugs. As with cocaine, each BZT analog (1.0-10.0 mg/kg i.p.) dose-dependently decreased maximal self-administration of d-methamphetamine (0.01-0.32 mg/kg/infusion) but was inactive against heroin (1.0-32.0 µg/kg/infusion) and ketamine (0.032-1.0 mg/kg/infusion) self-administration. Further, standard dopamine indirect-agonists [WIN35,428 ((-)-3β-(4-fluorophenyl)-tropan-2-β-carboxylic acid methyl ester tartrate), d-amphetamine (0.1-1.0 mg/kg i.p., each)] dose-dependently left-shifted self-administration dose-effect curves for d-methamphetamine, heroin, and ketamine. Noncompetitive NMDA-glutamate receptor/channel antagonists [(+)-MK-801 (0.01-0.1 mg/kg i.p.), memantine (1.0-10.0 mg/kg i.p.)] also left-shifted dose-effect curves for d-methamphetamine and ketamine (but not heroin) self-administration. The µ-agonists [dl-methadone and morphine (1.0-10.0 mg/kg i.p., each)] dose-dependently decreased maximal self-administration of µ-agonists (heroin, remifentanil) but not d-methamphetamine or ketamine self-administration. The µ-agonist-induced decreases were similar to the effects of BZT analogs on stimulant self-administration and effects of food prefeeding on responding maintained by food reinforcement. Radioligand-binding and behavioral studies suggested that inhibition of dopamine transporters and σ receptors were critical for blocking stimulant self-administration by BZT-analogs. Thus, the present results suggest that the effects of BZT analogs on stimulant self-administration are similar to effects of µ-agonists on µ-agonist self-administration and food prefeeding on food-reinforced responding, which implicates behavioral mechanisms for these effects and further supports development of atypical dopamine uptake inhibitors as medications for stimulant abuse.
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Affiliation(s)
- Takato Hiranita
- Psychobiology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland (T.H., S.J.K., G.T., T.A.K., J.L.K.); Division of Behavioral Biology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland (P.L.S.)
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Velázquez-Sánchez C, Ferragud A, Ramos-Miguel A, García-Sevilla JA, Canales JJ. Substituting a long-acting dopamine uptake inhibitor for cocaine prevents relapse to cocaine seeking. Addict Biol 2013; 18:633-43. [PMID: 22741574 DOI: 10.1111/j.1369-1600.2012.00458.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The treatment of cocaine addiction remains a challenge. The dopamine replacement approach in cocaine addiction involves the use of a competing dopaminergic agonist that might suppress withdrawal and drug craving in abstinent individuals. Although it has long been postulated that such an approach may be therapeutically successful, preclinical or clinical evidence showing its effectiveness to prevent relapse is scant. We used in rats a procedure that involved substitution of the N-substituted benztropine analog 3α-[bis(4'-fluorophenyl)methoxy]-tropane (AHN-1055), a long-acting dopamine uptake inhibitor (DUI), for cocaine. Maintenance treatment was self-administered. After extinction, reinstatement of drug seeking was induced by cocaine priming. We measured the contents of brain-derived neurotrophic factor (BDNF), c-Fos and Fas-associated death domain (FADD) proteins in the medial prefrontal cortex (mPFC) following reinstatement. DUI, but not amphetamine, substitution led to extinction of active lever presses, as did saline substitution. DUI substitution significantly reduced cocaine-induced reinstatement of drug-seeking behavior, which was strongly elicited after saline substitution. Rats passively yoked to DUI also showed reduced cocaine-primed reinstatement. Reductions in drug seeking during reinstatement were matched by downward shifts in the contents of BDNF, c-Fos and FADD proteins in the mPFC, which were elevated in relapsing rats. These data indicate that DUI substitution not only leads to extinction of self-administration behavior but also prevents reinstatement of drug seeking induced by cocaine re-exposure. Thus, DUI substitution therapy using compounds with low abuse potential, even if received passively in the context previously paired with drug taking, may provide an effective treatment for stimulant addiction.
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Velázquez-Sánchez C, García-Verdugo JM, Murga J, Canales JJ. The atypical dopamine transport inhibitor, JHW 007, prevents amphetamine-induced sensitization and synaptic reorganization within the nucleus accumbens. Prog Neuropsychopharmacol Biol Psychiatry 2013; 44:73-80. [PMID: 23385166 DOI: 10.1016/j.pnpbp.2013.01.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 01/25/2013] [Accepted: 01/25/2013] [Indexed: 11/17/2022]
Abstract
Benztropine (BZT) analogs, a family of agents with high affinity for the dopamine transporter have been postulated as potential treatments in stimulant abuse due to their ability to attenuate a wide range of effects evoked by psychomotor stimulants such as cocaine and amphetamine (AMPH). Repeating administration of drugs, including stimulants, can result in behavioral sensitization, a progressive increase in their psychomotor activating effects. We examined in mice the sensitizing effects and the neuroplasticity changes elicited by chronic AMPH exposure, and the modulation of these effects by the BZT derivative and atypical dopamine uptake inhibitor, JHW007, a candidate medication for stimulant abuse. The results indicated that JHW007 did not produce sensitized locomotor activity when given alone but prevented the sensitized motor behavior induced by chronic AMPH administration. Morphological analysis of medium spiny neurons of the nucleus accumbens revealed that JHW 007 prevented the neuroadaptations induced by chronic AMPH exposure, including increments in dendritic arborization, lengthening of dendritic processes and increases in spine density. Furthermore, data revealed that AMPH produced an increase in the density of asymmetric, possibly glutamatergic synapses in the nucleus accumbens, an effect that was also blocked by JHW007 pretreatment. The present observations demonstrate that JHW007 is able to prevent not only AMPH-induced behavioral sensitization but also the long-term structural changes induced by chronic AMPH in the nucleus accumbens. Such findings support the development and evaluation of BZT derivatives as possible leads for treatment in stimulant addiction.
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Affiliation(s)
- Clara Velázquez-Sánchez
- Behavioural Neuroscience, Department of Psychology, University of Canterbury, Christchurch, New Zealand
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Navarro G, Moreno E, Bonaventura J, Brugarolas M, Farré D, Aguinaga D, Mallol J, Cortés A, Casadó V, Lluís C, Ferre S, Franco R, Canela E, McCormick PJ. Cocaine inhibits dopamine D2 receptor signaling via sigma-1-D2 receptor heteromers. PLoS One 2013; 8:e61245. [PMID: 23637801 PMCID: PMC3630156 DOI: 10.1371/journal.pone.0061245] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 03/08/2013] [Indexed: 11/19/2022] Open
Abstract
Under normal conditions the brain maintains a delicate balance between inputs of reward seeking controlled by neurons containing the D1-like family of dopamine receptors and inputs of aversion coming from neurons containing the D2-like family of dopamine receptors. Cocaine is able to subvert these balanced inputs by altering the cell signaling of these two pathways such that D1 reward seeking pathway dominates. Here, we provide an explanation at the cellular and biochemical level how cocaine may achieve this. Exploring the effect of cocaine on dopamine D2 receptors function, we present evidence of σ1 receptor molecular and functional interaction with dopamine D2 receptors. Using biophysical, biochemical, and cell biology approaches, we discovered that D2 receptors (the long isoform of the D2 receptor) can complex with σ1 receptors, a result that is specific to D2 receptors, as D3 and D4 receptors did not form heteromers. We demonstrate that the σ1-D2 receptor heteromers consist of higher order oligomers, are found in mouse striatum and that cocaine, by binding to σ1 -D2 receptor heteromers, inhibits downstream signaling in both cultured cells and in mouse striatum. In contrast, in striatum from σ1 knockout animals these complexes are not found and this inhibition is not seen. Taken together, these data illuminate the mechanism by which the initial exposure to cocaine can inhibit signaling via D2 receptor containing neurons, destabilizing the delicate signaling balance influencing drug seeking that emanates from the D1 and D2 receptor containing neurons in the brain.
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Affiliation(s)
- Gemma Navarro
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) and Institute of Biomedicine of the University of Barcelona (IBUB) and Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Estefania Moreno
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) and Institute of Biomedicine of the University of Barcelona (IBUB) and Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Jordi Bonaventura
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) and Institute of Biomedicine of the University of Barcelona (IBUB) and Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Marc Brugarolas
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) and Institute of Biomedicine of the University of Barcelona (IBUB) and Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Daniel Farré
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) and Institute of Biomedicine of the University of Barcelona (IBUB) and Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - David Aguinaga
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) and Institute of Biomedicine of the University of Barcelona (IBUB) and Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Josefa Mallol
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) and Institute of Biomedicine of the University of Barcelona (IBUB) and Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Antoni Cortés
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) and Institute of Biomedicine of the University of Barcelona (IBUB) and Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Vicent Casadó
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) and Institute of Biomedicine of the University of Barcelona (IBUB) and Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Carmen Lluís
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) and Institute of Biomedicine of the University of Barcelona (IBUB) and Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Sergi Ferre
- National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Department of Health and Human Services, Baltimore, Maryland, United States of America
| | - Rafael Franco
- Centro de Investigación Médica Aplicada, Universidad de Navarra, Pamplona, Spain
| | - Enric Canela
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) and Institute of Biomedicine of the University of Barcelona (IBUB) and Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Peter J. McCormick
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED) and Institute of Biomedicine of the University of Barcelona (IBUB) and Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Barcelona, Spain
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Li L, Hiranita T, Hayashi S, Newman AH, Katz JL. The stereotypy-inducing effects of N-substituted benztropine analogs alone and in combination with cocaine do not account for their blockade of cocaine self-administration. Psychopharmacology (Berl) 2013; 225:733-42. [PMID: 22975727 PMCID: PMC4472487 DOI: 10.1007/s00213-012-2862-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 08/22/2012] [Indexed: 11/24/2022]
Abstract
RATIONALE Previous studies have demonstrated that several N-substituted 4', 4″-diF-benztropine (BZT) analogs with high dopamine transporter affinity selectively decreased cocaine self-administration without affecting food-maintained behavior in rats. OBJECTIVES The present study examined if the decreases in cocaine self-administration are due to competition from excess behavioral activity (hyperlocomotion or stereotypy) induced by the BZT analogs alone or in combination with cocaine. RESULTS Pretreatments with the typical dopamine uptake inhibitor methylphenidate [1.0, 3.2, and 10 mg/kg, intraperitoneally (i.p.)] dose-dependently shifted the cocaine self-administration dose-effect curve (0, 0.032, 0.1, 0.32, and 1.0 mg/kg/injection) leftward. The shift in the dose-effect curve was obtained at doses of methylphenidate that, when administered alone, also decreased food-maintained behavior and increased locomotor activity and stereotypy. In contrast, the N-substituted BZT analogs, JHW 007 (1.0, 3.2, and 10 mg/kg, i.p.), AHN 1-055 (10 mg/kg), and, AHN 2-005 (10 mg/kg), as previously reported, decreased the maximum for the cocaine self-administration dose-effect curve, and did so at doses that were virtually without effects on food-maintained behavior. Further, the BZT analogs alone had minimal effects on locomotor activity and stereotypies and did not appreciably change the effects of cocaine on these measures when administered in combination with cocaine. CONCLUSIONS The present results suggest that the decrease in cocaine self-administration produced by the N-substituted BZT analogs is due to an antagonism of the reinforcing effects of cocaine rather than due to interference from competing behavioral overstimulation, and further supports the development of N-substituted BZT analogs as medications to treat cocaine abuse.
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Affiliation(s)
- Libin Li
- Psychobiology, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD 21224
| | - Takato Hiranita
- Psychobiology, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD 21224
| | - Shuichiro Hayashi
- Psychobiology, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD 21224
| | - Amy H. Newman
- Medicinal Chemistry Sections, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD 21224
| | - Jonathan L. Katz
- Psychobiology, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD 21224
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22
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Therapeutic-like properties of a dopamine uptake inhibitor in animal models of amphetamine addiction. Int J Neuropsychopharmacol 2011; 14:655-65. [PMID: 20735880 DOI: 10.1017/s1461145710000969] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
N-substituted benztropine (BZT) analogs are molecules that display high affinity for the dopamine transporter (DAT), therapeutic-like effects in animal models of cocaine abuse, and psychopharmacological characteristics consistent with those of a substitute medication for cocaine addiction. Since amphetamine (Amph) and cocaine share mechanisms of action at the DAT, we evaluated the effectiveness of a BZT analog in animal models of Amph addiction. We tested in mice and rats the effects of the BZT derivative, 3α-[bis(4-fluorophenyl)methoxy]-tropane (AHN-1055), on Amph-induced conditioned place preference (CPP), locomotor activity, sensitization, self-administration and ΔFosB accumulation in the nucleus accumbens (NAc). The results showed that AHN-1055 did not produce rewarding, stimulant, or sensitized locomotor effects in mice when administered alone but it readily blocked the rewarding, stimulant, and sensitizing effects of repeated Amph exposure. Furthermore, in mice undergoing conditioning in the CPP paradigm, the BZT analog prevented the accumulation of ΔFosB protein induced in the NAc shell region by Amph treatment. Notably, treatment with AHN-1055 dose-dependently reduced Amph self-administration in rats with a steady history of voluntary Amph intake. These results provide a straightforward demonstration that a BZT derivative with binding affinity for DAT exhibits high efficacy in animal models of Amph abuse, suggesting that the novel generation of BZT analogs could have wider therapeutic applications in stimulant-spectrum disorders than those previously recognized.
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Lin Z, Canales JJ, Björgvinsson T, Thomsen MM, Qu H, Liu QR, Torres GE, Caine SB. Monoamine transporters: vulnerable and vital doorkeepers. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 98:1-46. [PMID: 21199769 PMCID: PMC3321928 DOI: 10.1016/b978-0-12-385506-0.00001-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Transporters of dopamine, serotonin, and norepinephrine have been empirically used as medication targets for several mental illnesses in the last decades. These protein-targeted medications are effective only for subpopulations of patients with transporter-related brain disorders. Since the cDNA clonings in early 1990s, molecular studies of these transporters have revealed a wealth of information about the transporters' structure-activity relationship (SAR), neuropharmacology, cell biology, biochemistry, pharmacogenetics, and the diseases related to the human genes encoding these transporters among related regulators. Such new information creates a unique opportunity to develop transporter-specific medications based on SAR, mRNA, DNA, and perhaps transporter trafficking regulation for a number of highly relevant diseases including substance abuse, depression, schizophrenia, and Parkinson's disease.
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Affiliation(s)
- Zhicheng Lin
- Department of Psychiatry, Harvard Medical School and Division of Alcohol and Drug Abuse, McLean Hospital, Belmont, MA 02478, USA
| | - Juan J. Canales
- Department of Psychology, Behavioural Neuroscience, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
| | - Thröstur Björgvinsson
- Behavioral Health Partial Hospital and Psychology Internship Programs, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA
| | - Morgane M. Thomsen
- Department of Psychiatry, Harvard Medical School and Division of Alcohol and Drug Abuse, McLean Hospital, Belmont, MA 02478, USA
| | - Hong Qu
- Center for Bioinformatics, National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University. Beijing, 100871 China
| | - Qing-Rong Liu
- Behavioral Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, NIH/DHHS, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Gonzalo E. Torres
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - S. Barak Caine
- Department of Psychiatry, Harvard Medical School and Division of Alcohol and Drug Abuse, McLean Hospital, Belmont, MA 02478, USA
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24
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Is slow-onset long-acting monoamine transport blockade to cocaine as methadone is to heroin? Implication for anti-addiction medications. Neuropsychopharmacology 2010; 35:2564-78. [PMID: 20827272 PMCID: PMC2978747 DOI: 10.1038/npp.2010.133] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The success of methadone in treating opiate addiction has suggested that long-acting agonist therapies may be similarly useful for treating cocaine addiction. Here, we examined this hypothesis, using the slow-onset long-acting monoamine reuptake inhibitor 31,345, a trans-aminotetralin analog, in a variety of addiction-related animal models, and compared it with methadone's effects on heroin's actions in the same animal models. Systemic administration of 31,345 produced long-lasting enhancement of electrical brain-stimulation reward (BSR) and extracellular nucleus accumbens (NAc) dopamine (DA). Pretreatment with 31,345 augmented cocaine-enhanced BSR, prolonged cocaine-enhanced NAc DA, and produced a long-term (24-48 h) reduction in cocaine self-administration rate without obvious extinction pattern, suggesting an additive effect of 31,345 with cocaine. In contrast, methadone pretreatment not only dose-dependently inhibited heroin self-administration with an extinction pattern but also dose-dependently inhibited heroin-enhanced BSR and NAc DA, suggesting functional antagonism by methadone of heroin's actions. In addition, 31,345 appears to possess significant abuse liability, as it produces dose-dependent enhancement of BSR and NAc DA, maintains a low rate of self-administration behavior, and dose-dependently reinstates drug-seeking behavior. In contrast, methadone only partially maintains self-administration with an extinction pattern, and fails to induce reinstatement of drug-seeking behavior. These findings suggest that 31,345 is a cocaine-like slow-onset long-acting monoamine transporter inhibitor that may act as an agonist therapy for cocaine addiction. However, its pattern of action appears to be significantly different from that of methadone. Ideal agonist substitutes for cocaine should fully emulate methadone's actions, that is, functionally antagonizing cocaine's action while blocking monoamine transporters to augment synaptic DA.
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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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26
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Hernandez-Rabaza V, Navarro-Mora G, Velazquez-Sanchez C, Ferragud A, Marin MP, Garcia-Verdugo JM, Renau-Piqueras J, Canales JJ. Neurotoxicity and persistent cognitive deficits induced by combined MDMA and alcohol exposure in adolescent rats. Addict Biol 2010; 15:413-23. [PMID: 21040238 DOI: 10.1111/j.1369-1600.2010.00259.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Recent trend assessments of drug consumption reveal an increase in the simultaneous use of several drugs at raves, clubs and college settings among youngsters and young adults. We studied in adolescent rats the effects of repeated exposure to cocaine and 3,4-methylenedioxymethanphetamine (MDMA, ecstasy), given alone or in combination with alcohol, on memory performance, adult hippocampal neurogenesis and neurotoxicity. Rats were trained two weeks after the drug treatments in the radial arm maze. The results showed that only rats exposed to combinations of alcohol and MDMA exhibited significant memory deficits. Alcohol, MDMA and combinations thereof significantly decreased 5-bromodeoxyuridine labeling in the dentate gyrus (DG), indicating reduced survival of neuronal precursors. None of the treatments altered the length of the dendritic arbors of doublecortin (DCX)-positive neurons or the number and length of DCX-negative gaps in the DG. Thus, changes in adult neurogenesis were not causally related to the cognitive alterations induced by the treatments. Only the combination of alcohol and MDMA significantly decreased the population of mature granule neurons in the DG and increased the presence of cluster of differentiation 11b+ reactive microglia in the bordering areas of the subgranular zone. Critically, memory impairment was correlated with granule cell depletion. These observations demonstrate that exposure to alcohol and MDMA during adolescence, at doses that do not provoke apparent cognitive impairment when given separately, causes neurotoxic alterations affecting the DG region as well as persistent memory deficits. The findings highlight the elevated risk associated with the concurrent recreational use of alcohol and MDMA.
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Affiliation(s)
- Vicente Hernandez-Rabaza
- Biopsychology & Comparative Neuroscience, ICBiBE, University of Valencia-FGUV & Red de Trastornos Adictivos, RETICS, Spain
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27
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Kopajtic TA, Liu Y, Surratt CK, Donovan DM, Newman AH, Katz JL. Dopamine transporter-dependent and -independent striatal binding of the benztropine analog JHW 007, a cocaine antagonist with low abuse liability. J Pharmacol Exp Ther 2010; 335:703-14. [PMID: 20855444 DOI: 10.1124/jpet.110.171629] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The benztropine analog N-(n-butyl)-3α-[bis(4'-fluorophenyl)methoxy]-tropane (JHW 007) displays high affinity for the dopamine transporter (DAT), but unlike typical DAT ligands, has relatively low abuse liability and blocks the effects of cocaine, including its self-administration. To determine sites responsible for the cocaine antagonist effects of JHW 007, its in vitro binding was compared with that of methyl (1R,2S,3S,5S)-3-(4-fluorophenyl)-8-methyl-8-azabicyclo[3.2.1]octane-2-carboxylate (WIN 35428) in rats, mice, and human DAT (hDAT)-transfected cells. A one-site model, with K(d) values of 4.21 (rat) and 8.99 nM (mouse) best fit the [(3)H]WIN 35428 data. [(3)H]JHW 007 binding best fit a two-site model (rat, 7.40/4400 nM; mouse, 8.18/2750 nM), although a one-site fit was observed with hDAT membranes (43.7 nM). Drugs selective for the norepinephrine and serotonin transporters had relatively low affinity in competition with [(3)H]JHW 007 binding, as did drugs selective for other sites identified previously as potential JHW 007 binding sites. The association of [(3)H]WIN 35428 best fit a one-phase model, whereas the association of [(3)H]JHW 007 best fit a two-phase model in all tissues. Because cocaine antagonist effects of JHW 007 have been observed previously soon after injection, its rapid association observed here may contribute to those effects. Multiple [(3)H]JHW 007 binding sites were obtained in tissue from mice lacking the DAT, suggesting these as yet unidentified sites as potential contributors to the cocaine antagonist effects of JHW 007. Unlike WIN 35428, the binding of JHW 007 was Na(+)-independent. This feature of JHW 007 has been linked to the conformational status of the DAT, which in turn may contribute to the antagonism of cocaine.
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Affiliation(s)
- Theresa A Kopajtic
- Psychobiology Section, Medications Discovery Research Branch, National Institute on Drug Abuse Intramural Research Program, Baltimore, Maryland 21224, USA
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28
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Velázquez-Sánchez C, Ferragud A, Murga J, Cardá M, Canales JJ. The high affinity dopamine uptake inhibitor, JHW 007, blocks cocaine-induced reward, locomotor stimulation and sensitization. Eur Neuropsychopharmacol 2010; 20:501-8. [PMID: 20413276 DOI: 10.1016/j.euroneuro.2010.03.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Revised: 01/12/2010] [Accepted: 03/18/2010] [Indexed: 11/30/2022]
Abstract
The discovery and evaluation of high affinity dopamine transport inhibitors with low abuse liability is an important step toward the development of efficacious medications for cocaine addiction. We examined in mice the behavioural effects of (N-(n-butyl)-3alpha-[bis(4'-fluorophenyl)methoxy]-tropane) (JHW 007), a benztropine (BZT) analogue that blocks dopamine uptake, and assessed its potential to influence the actions of cocaine in clinically-relevant models of cocaine addiction. In the conditioned place preference (CPP) paradigm, JHW 007 exposure did not produce place conditioning within an ample dose range but effectively blocked the CPP induced by cocaine administration. Similarly, in the CPP apparatus JHW 007 treatment failed to stimulate locomotor activity at any dose but dose-dependently suppressed the hyperactivity evoked by cocaine treatment. In locomotor sensitization assays performed in the open field, JHW 007 did not produce sensitized locomotor behaviour when given alone, but it prevented the sensitized component of the locomotor response elicited by subchronic (8-day) cocaine exposure. In the elevated plus maze (EPM), acute treatment with JHW 007, cocaine and combinations of the BZT analogue and cocaine produced an anxiogenic-like profile. Re-test in the EPM following subchronic (8-day) exposure enhanced the anxiogenic-like effect of the same drug treatments. The present findings indicate that JHW 007 exposure counteracts some critical behavioural correlates of cocaine treatment, including conditioned reward, locomotor stimulation and sensitization, and lend support to the further development of BZT analogues as potential replacement medications in cocaine addiction.
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Affiliation(s)
- C Velázquez-Sánchez
- Biopsychology and Comparative Neuroscience Group, Cavanilles Institute (ICBiBE), University of Valencia-FGUV, Valencia, Spain.
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29
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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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