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Mayer FP, Stewart A, Blakely RD. Leaky lessons learned: Efflux prone dopamine transporter variant reveals sex and circuit specific contributions of D2 receptor signalling to neuropsychiatric disease. Basic Clin Pharmacol Toxicol 2024; 134:206-218. [PMID: 37987120 DOI: 10.1111/bcpt.13964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 11/14/2023] [Accepted: 11/17/2023] [Indexed: 11/22/2023]
Abstract
Aberrant dopamine (DA) signalling has been implicated in various neuropsychiatric disorders, including attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), schizophrenia, bipolar disorder (BPD) and addiction. The availability of extracellular DA is sculpted by the exocytotic release of vesicular DA and subsequent transporter-mediated clearance, rendering the presynaptic DA transporter (DAT) a crucial regulator of DA neurotransmission. D2-type DA autoreceptors (D2ARs) regulate multiple aspects of DA homeostasis, including (i) DA synthesis, (ii) vesicular release, (iii) DA neuron firing and (iv) the surface expression of DAT and DAT-mediated DA clearance. The DAT Val559 variant, identified in boys with ADHD or ASD, as well as in a girl with BPD, supports anomalous DA efflux (ADE), which we have shown drives tonic activation of D2ARs. Through ex vivo and in vivo studies of the DAT Val559 variant using transgenic knock-in mice, we have uncovered a circuit and sex-specific capacity of D2ARs to regulate DAT, which consequently disrupts DA signalling and behaviour differently in males and females. Our studies reveal the ability of the construct-valid DAT Val559 model to elucidate endogenous mechanisms that support DA signalling, findings that may be of translational and/or therapeutic importance.
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Affiliation(s)
- Felix P Mayer
- Department of Biomedical Science, Florida Atlantic University, Jupiter, Florida, USA
- Stiles-Nicholson Brain Institute, Florida Atlantic University, Jupiter, Florida, USA
| | - Adele Stewart
- Department of Biomedical Science, Florida Atlantic University, Jupiter, Florida, USA
- Stiles-Nicholson Brain Institute, Florida Atlantic University, Jupiter, Florida, USA
| | - Randy D Blakely
- Department of Biomedical Science, Florida Atlantic University, Jupiter, Florida, USA
- Stiles-Nicholson Brain Institute, Florida Atlantic University, Jupiter, Florida, USA
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2
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Gradisch R, Schlögl K, Lazzarin E, Niello M, Maier J, Mayer FP, Alves da Silva L, Skopec SMC, Blakely RD, Sitte HH, Mihovilovic MD, Stockner T. Ligand coupling mechanism of the human serotonin transporter differentiates substrates from inhibitors. Nat Commun 2024; 15:417. [PMID: 38195746 PMCID: PMC10776687 DOI: 10.1038/s41467-023-44637-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 12/22/2023] [Indexed: 01/11/2024] Open
Abstract
The presynaptic serotonin transporter (SERT) clears extracellular serotonin following vesicular release to ensure temporal and spatial regulation of serotonergic signalling and neurotransmitter homeostasis. Prescription drugs used to treat neurobehavioral disorders, including depression, anxiety, and obsessive-compulsive disorder, trap SERT by blocking the transport cycle. In contrast, illicit drugs of abuse like amphetamines reverse SERT directionality, causing serotonin efflux. Both processes result in increased extracellular serotonin levels. By combining molecular dynamics simulations with biochemical experiments and using a homologous series of serotonin analogues, we uncovered the coupling mechanism between the substrate and the transporter, which triggers the uptake of serotonin. Free energy analysis showed that only scaffold-bound substrates could initiate SERT occlusion through attractive long-range electrostatic interactions acting on the bundle domain. The associated spatial requirements define substrate and inhibitor properties, enabling additional possibilities for rational drug design approaches.
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Affiliation(s)
- Ralph Gradisch
- Medical University of Vienna, Institute of Physiology and Pharmacology, Waehringer Straße 13A, 1090, Vienna, Austria
| | - Katharina Schlögl
- TU Wien, Institute of Applied Synthetic Chemistry, Getreidemarkt 9, 1060, Vienna, Austria
| | - Erika Lazzarin
- Medical University of Vienna, Institute of Physiology and Pharmacology, Waehringer Straße 13A, 1090, Vienna, Austria
| | - Marco Niello
- Medical University of Vienna, Institute of Physiology and Pharmacology, Waehringer Straße 13A, 1090, Vienna, Austria
- Genetics of Cognition Laboratory, Neuroscience area, Istituto Italiano di Tecnologia, via Morego, 30, 16163, Genova, Italy
| | - Julian Maier
- Medical University of Vienna, Institute of Physiology and Pharmacology, Waehringer Straße 13A, 1090, Vienna, Austria
| | - Felix P Mayer
- Florida Atlantic University, Department of Biomedical Science, Jupiter, FL, 33458, USA
- Stiles-Nicholson Brain Institute, Jupiter, FL, 33458, USA
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200, Copenhagen, Denmark
| | - Leticia Alves da Silva
- Medical University of Vienna, Institute of Physiology and Pharmacology, Waehringer Straße 13A, 1090, Vienna, Austria
| | - Sophie M C Skopec
- Medical University of Vienna, Institute of Physiology and Pharmacology, Waehringer Straße 13A, 1090, Vienna, Austria
| | - Randy D Blakely
- Florida Atlantic University, Department of Biomedical Science, Jupiter, FL, 33458, USA
- Stiles-Nicholson Brain Institute, Jupiter, FL, 33458, USA
| | - Harald H Sitte
- Medical University of Vienna, Institute of Physiology and Pharmacology, Waehringer Straße 13A, 1090, Vienna, Austria
- Al-Ahliyya Amman University, Hourani Center for Applied Scientific Research, Amman, Jordan
- Medical University of Vienna, Center for Addiction Research and Science, Waehringer Straße 13A, 1090, Vienna, Austria
| | - Marko D Mihovilovic
- TU Wien, Institute of Applied Synthetic Chemistry, Getreidemarkt 9, 1060, Vienna, Austria
| | - Thomas Stockner
- Medical University of Vienna, Institute of Physiology and Pharmacology, Waehringer Straße 13A, 1090, Vienna, Austria.
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3
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Mayer FP, Niello M, Bulling S, Zhang YW, Li Y, Kudlacek O, Holy M, Kooti F, Sandtner W, Rudnick G, Schmid D, Sitte HH. Mephedrone induces partial release at human dopamine transporters but full release at human serotonin transporters. Neuropharmacology 2023; 240:109704. [PMID: 37703919 DOI: 10.1016/j.neuropharm.2023.109704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 07/07/2023] [Accepted: 08/31/2023] [Indexed: 09/15/2023]
Abstract
Mephedrone (4-methylmethcathinone) is a cathinone derivative that is recreationally consumed for its energizing and empathogenic effects. The stimulating properties are believed to arise from the ability of mephedrone to interact with the high-affinity transporters for dopamine (DA) (DAT) and norepinephrine (NET), whereas the entactogenic effect presumably relies on its activity at the serotonin (5-HT) transporter (SERT). Early studies found that mephedrone acts as a releaser at NET, DAT and SERT, and thus promotes efflux of the respective monoamines. Evidence linked drug-induced reverse transport of 5-HT via SERT to prosocial effects, whereas activity at DAT is strongly correlated with abuse liability. Consequently, we sought to evaluate the pharmacology of mephedrone at human (h) DAT and SERT, heterologously expressed in human embryonic kidney 293 cells, in further detail. In line with previous studies, we report that mephedrone evokes carrier-mediated release via hDAT and hSERT. We found this effect to be sensitive to the protein kinase C inhibitor GF109203X. Electrophysiological recordings revealed that mephedrone is actively transported by hDAT and hSERT. However, mephedrone acts as a full substrate of hSERT but as a partial substrate of hDAT. Furthermore, when compared to fully efficacious releasing agents at hDAT and hSERT (i.e. S(+)-amphetamine and para-chloroamphetamine, respectively) mephedrone displays greater efficacy as a releaser at hSERT than at hDAT. In summary, this study provides additional insights into the molecular mechanism of action of mephedrone at hDAT and hSERT.
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Affiliation(s)
- Felix P Mayer
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13a, A-1090, Vienna, Austria
| | - Marco Niello
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13a, A-1090, Vienna, Austria
| | - Simon Bulling
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13a, A-1090, Vienna, Austria
| | - Yuan-Wei Zhang
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06520-8066, USA
| | - Yang Li
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13a, A-1090, Vienna, Austria
| | - Oliver Kudlacek
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13a, A-1090, Vienna, Austria
| | - Marion Holy
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13a, A-1090, Vienna, Austria
| | - Fatemeh Kooti
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13a, A-1090, Vienna, Austria
| | - Walter Sandtner
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13a, A-1090, Vienna, Austria
| | - Gary Rudnick
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06520-8066, USA
| | - Diethart Schmid
- Institute for Physiology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13a, A-1090, Vienna, Austria
| | - Harald H Sitte
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Waehringer Strasse 13a, A-1090, Vienna, Austria; Hourani Center for Applied Scientific Research, Al-Ahliyya Amman University, Amman, Jordan; Center for Addiction Research and Science - AddRess, Medical University of Vienna, Waehringer Strasse 13a, A-1090, Vienna, Austria.
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4
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Clauss NJ, Mayer FP, Owens WA, Vitela M, Clarke KM, Bowman MA, Horton RE, Gründemann D, Schmid D, Holy M, Gould GG, Koek W, Sitte HH, Daws LC. Ethanol inhibits dopamine uptake via organic cation transporter 3: Implications for ethanol and cocaine co-abuse. Mol Psychiatry 2023; 28:2934-2945. [PMID: 37308680 PMCID: PMC10615754 DOI: 10.1038/s41380-023-02064-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 12/20/2022] [Accepted: 03/29/2023] [Indexed: 06/14/2023]
Abstract
Concurrent cocaine and alcohol use is among the most frequent drug combination, and among the most dangerous in terms of deleterious outcomes. Cocaine increases extracellular monoamines by blocking dopamine (DA), norepinephrine (NE) and serotonin (5-HT) transporters (DAT, NET and SERT, respectively). Likewise, ethanol also increases extracellular monoamines, however evidence suggests that ethanol does so independently of DAT, NET and SERT. Organic cation transporter 3 (OCT3) is an emergent key player in the regulation of monoamine signaling. Using a battery of in vitro, in vivo electrochemical, and behavioral approaches, as well as wild-type and constitutive OCT3 knockout mice, we show that ethanol's actions to inhibit monoamine uptake are dependent on OCT3. These findings provide a novel mechanistic basis whereby ethanol enhances the neurochemical and behavioral effects of cocaine and encourage further research into OCT3 as a target for therapeutic intervention in the treatment of ethanol and ethanol/cocaine use disorders.
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Affiliation(s)
- N J Clauss
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - F P Mayer
- Center for Physiology and Pharmacology, Medical University of Vienna, 1090, Vienna, Austria
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, DK-2200, Denmark
| | - W A Owens
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - M Vitela
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - K M Clarke
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - M A Bowman
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - R E Horton
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - D Gründemann
- Department of Pharmacology, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50931, Cologne, Germany
| | - D Schmid
- Center for Physiology and Pharmacology, Medical University of Vienna, 1090, Vienna, Austria
| | - M Holy
- Center for Physiology and Pharmacology, Medical University of Vienna, 1090, Vienna, Austria
| | - G G Gould
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - W Koek
- Department of Cell Systems and Anatomy, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - H H Sitte
- Center for Physiology and Pharmacology, Medical University of Vienna, 1090, Vienna, Austria
- Center for Addiction Research and Science, Medical University Vienna, Waehringerstrasse 13 A, 1090, Vienna, Austria
| | - L C Daws
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA.
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA.
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5
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Mayer FP, Stewart A, Varman DR, Moritz AE, Foster JD, Owens AW, Areal LB, Gowrishankar R, Velez M, Wickham K, Phelps H, Katamish R, Rabil M, Jayanthi LD, Vaughan RA, Daws LC, Blakely RD, Ramamoorthy S. Kappa Opioid Receptor Antagonism Rescues Genetic Perturbation of Dopamine Homeostasis: Molecular, Physiological and Behavioral Consequences. bioRxiv 2023:2023.05.03.539310. [PMID: 37205452 PMCID: PMC10187322 DOI: 10.1101/2023.05.03.539310] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Aberrant dopamine (DA) signaling is implicated in schizophrenia, bipolar disorder (BPD), autism spectrum disorder (ASD), substance use disorder, and attention-deficit/hyperactivity disorder (ADHD). Treatment of these disorders remains inadequate. We established that the human DA transporter (DAT) coding variant (DAT Val559), identified in individuals with ADHD, ASD, or BPD, exhibits anomalous DA efflux (ADE) that is blocked by therapeutic amphetamines and methylphenidate. As the latter agents have high abuse liability, we exploited DAT Val559 knock-in mice to identify non-addictive agents that can normalize DAT Val559 functional and behavioral effects ex vivo and in vivo. Kappa opioid receptors (KORs) are expressed by DA neurons and modulate DA release and clearance, suggesting that targeting KORs might offset the effects of DAT Val559. We establish that enhanced DAT Thr53 phosphorylation and increased DAT surface trafficking associated with DAT Val559 expression are mimicked by KOR agonism of wildtype preparations and rescued by KOR antagonism of DAT Val559 ex vivo preparations. Importantly, KOR antagonism also corrected in vivo DA release and sex-dependent behavioral abnormalities. Given their low abuse liability, our studies with a construct valid model of human DA associated disorders reinforce considerations of KOR antagonism as a pharmacological strategy to treat DA associated brain disorders.
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Affiliation(s)
- Felix P Mayer
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, FL, USA
- Stiles-Nicholson Brain Institute, Florida Atlantic University, Jupiter, FL, USA
| | - Adele Stewart
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, FL, USA
- Stiles-Nicholson Brain Institute, Florida Atlantic University, Jupiter, FL, USA
| | - Durairaj Ragu Varman
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA
| | - Amy E Moritz
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - James D Foster
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Anthony W Owens
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, TX, USA
| | - Lorena B Areal
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, FL, USA
| | - Raajaram Gowrishankar
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, FL, USA
| | - Michelle Velez
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, FL, USA
| | - Kyria Wickham
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, FL, USA
| | - Hannah Phelps
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, FL, USA
| | - Rania Katamish
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, FL, USA
| | - Maximilian Rabil
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, FL, USA
| | - Lankupalle D Jayanthi
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA
| | - Roxanne A Vaughan
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Lynette C Daws
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, TX, USA
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, TX, USA
| | - Randy D Blakely
- Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, FL, USA
- Stiles-Nicholson Brain Institute, Florida Atlantic University, Jupiter, FL, USA
| | - Sammanda Ramamoorthy
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA
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6
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Mayer FP, Luethi D, Areal LB, Sitte HH. Editorial: Old and new psychoactive substances: Pharmacology and potential applications. Front Psychiatry 2023; 13:1087005. [PMID: 36684007 PMCID: PMC9846803 DOI: 10.3389/fpsyt.2022.1087005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 12/14/2022] [Indexed: 01/06/2023] Open
Affiliation(s)
- Felix P Mayer
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, United States
| | - Dino Luethi
- Division of Clinical Pharmacology and Toxicology, University Hospital Basel and University of Basel, Basel, Switzerland
| | - Lorena B Areal
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, United States
| | - Harald H Sitte
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
- AddRess, Center for Addiction Research and Science, Medical University of Vienna, Vienna, Austria
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Mayer FP, Niello M, Cintulova D, Sideromenos S, Maier J, Li Y, Bulling S, Kudlacek O, Schicker K, Iwamoto H, Deng F, Wan J, Holy M, Katamish R, Sandtner W, Li Y, Pollak DD, Blakely RD, Mihovilovic MD, Baumann MH, Sitte HH. Serotonin-releasing agents with reduced off-target effects. Mol Psychiatry 2023; 28:722-732. [PMID: 36352123 PMCID: PMC9645344 DOI: 10.1038/s41380-022-01843-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 10/06/2022] [Accepted: 10/12/2022] [Indexed: 11/10/2022]
Abstract
Increasing extracellular levels of serotonin (5-HT) in the brain ameliorates symptoms of depression and anxiety-related disorders, e.g., social phobias and post-traumatic stress disorder. Recent evidence from preclinical and clinical studies established the therapeutic potential of drugs inducing the release of 5-HT via the 5-HT-transporter. Nevertheless, current 5-HT releasing compounds under clinical investigation carry the risk for abuse and deleterious side effects. Here, we demonstrate that S-enantiomers of certain ring-substituted cathinones show preference for the release of 5-HT ex vivo and in vivo, and exert 5-HT-associated effects in preclinical behavioral models. Importantly, the lead cathinone compounds (1) do not induce substantial dopamine release and (2) display reduced off-target activity at vesicular monoamine transporters and 5-HT2B-receptors, indicative of low abuse-liability and low potential for adverse events. Taken together, our findings identify these agents as lead compounds that may prove useful for the treatment of disorders where elevation of 5-HT has proven beneficial.
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Affiliation(s)
- Felix P. Mayer
- grid.22937.3d0000 0000 9259 8492Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Waehringer Strasse 13a, 1090 Vienna, Austria ,grid.255951.fDepartment of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, FL 33458 USA
| | - Marco Niello
- grid.22937.3d0000 0000 9259 8492Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Waehringer Strasse 13a, 1090 Vienna, Austria
| | - Daniela Cintulova
- grid.5329.d0000 0001 2348 4034Institute of Applied Synthetic Chemistry, TU Wien, Vienna, Austria
| | - Spyridon Sideromenos
- grid.22937.3d0000 0000 9259 8492Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Vienna, Austria
| | - Julian Maier
- grid.22937.3d0000 0000 9259 8492Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Waehringer Strasse 13a, 1090 Vienna, Austria
| | - Yang Li
- grid.22937.3d0000 0000 9259 8492Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Waehringer Strasse 13a, 1090 Vienna, Austria ,grid.8547.e0000 0001 0125 2443Present Address: Institutes of Brain Science, Fudan University, Shanghai, 200032 China
| | - Simon Bulling
- grid.22937.3d0000 0000 9259 8492Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Waehringer Strasse 13a, 1090 Vienna, Austria
| | - Oliver Kudlacek
- grid.22937.3d0000 0000 9259 8492Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Waehringer Strasse 13a, 1090 Vienna, Austria
| | - Klaus Schicker
- grid.22937.3d0000 0000 9259 8492Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Waehringer Strasse 13a, 1090 Vienna, Austria
| | - Hideki Iwamoto
- grid.255951.fStiles-Nicholson Brain Institute and Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, FL 33458 USA
| | - Fei Deng
- grid.11135.370000 0001 2256 9319IDG McGovern Institute for Brain Research, Peking University, 100871 Beijing, China
| | - Jinxia Wan
- grid.11135.370000 0001 2256 9319IDG McGovern Institute for Brain Research, Peking University, 100871 Beijing, China
| | - Marion Holy
- grid.22937.3d0000 0000 9259 8492Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Waehringer Strasse 13a, 1090 Vienna, Austria
| | - Rania Katamish
- grid.255951.fDepartment of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, FL 33458 USA
| | - Walter Sandtner
- grid.22937.3d0000 0000 9259 8492Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Waehringer Strasse 13a, 1090 Vienna, Austria
| | - Yulong Li
- grid.11135.370000 0001 2256 9319IDG McGovern Institute for Brain Research, Peking University, 100871 Beijing, China
| | - Daniela D. Pollak
- grid.22937.3d0000 0000 9259 8492Department of Neurophysiology and Neuropharmacology, Medical University of Vienna, Vienna, Austria
| | - Randy D. Blakely
- grid.255951.fDepartment of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, FL 33458 USA ,grid.255951.fStiles-Nicholson Brain Institute and Department of Biomedical Science, Charles E. Schmidt College of Medicine, Florida Atlantic University, Jupiter, FL 33458 USA
| | - Marko D. Mihovilovic
- grid.5329.d0000 0001 2348 4034Institute of Applied Synthetic Chemistry, TU Wien, Vienna, Austria
| | - Michael H. Baumann
- grid.94365.3d0000 0001 2297 5165Designer Drug Research Unit, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224 USA
| | - Harald H. Sitte
- grid.22937.3d0000 0000 9259 8492Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Waehringer Strasse 13a, 1090 Vienna, Austria ,grid.22937.3d0000 0000 9259 8492AddRess, Center for Addiction Research and Science, Medical University of Vienna, Vienna, Austria
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8
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Stewart A, Mayer FP, Gowrishankar R, Davis GL, Areal LB, Gresch PJ, Katamish RM, Peart R, Stilley SE, Spiess K, Rabil MJ, Diljohn FA, Wiggins AE, Vaughan RA, Hahn MK, Blakely RD. Behaviorally penetrant, anomalous dopamine efflux exposes sex and circuit dependent regulation of dopamine transporters. Mol Psychiatry 2022; 27:4869-4880. [PMID: 36117213 DOI: 10.1038/s41380-022-01773-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 08/18/2022] [Accepted: 08/31/2022] [Indexed: 01/19/2023]
Abstract
Virtually all neuropsychiatric disorders display sex differences in prevalence, age of onset, and/or clinical symptomology. Although altered dopamine (DA) signaling is a feature of many of these disorders, sex-dependent mechanisms uniquely responsive to DA that drive sex-dependent behaviors remain unelucidated. Previously, we established that anomalous DA efflux (ADE) is a prominent feature of the DA transporter (DAT) variant Val559, a coding substitution identified in two male-biased disorders: attention-deficit/hyperactivity disorder and autism spectrum disorder. In vivo, Val559 ADE induces activation of nigrostriatal D2-type DA autoreceptors (D2ARs) that magnifies inappropriate, nonvesicular DA release by elevating phosphorylation and surface trafficking of ADE-prone DAT proteins. Here we demonstrate that DAT Val559 mice exhibit sex-dependent alterations in psychostimulant responses, social behavior, and cognitive performance. In a search for underlying mechanisms, we discovered that the ability of ADE to elicit D2AR regulation of DAT is both sex and circuit-dependent, with dorsal striatum D2AR/DAT coupling evident only in males, whereas D2AR/DAT coupling in the ventral striatum is exclusive to females. Moreover, systemic administration of the D2R antagonist sulpiride, which precludes ADE-driven DAT trafficking, can normalize DAT Val559 behavioral changes unique to each sex and without effects on the opposite sex or wildtype mice. Our studies support the sex- and circuit dependent capacity of D2ARs to regulate DAT as a critical determinant of the sex-biased effects of perturbed DA signaling in neurobehavioral disorders. Moreover, our work provides a cogent example of how a shared biological insult drives alternative physiological and behavioral trajectories as opposed to resilience.
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Affiliation(s)
- Adele Stewart
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA.,Stiles-Nicholson Brain Institute, Florida Atlantic University, Jupiter, FL, USA
| | - Felix P Mayer
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA
| | | | - Gwynne L Davis
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA
| | - Lorena B Areal
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA
| | - Paul J Gresch
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA.,Stiles-Nicholson Brain Institute, Florida Atlantic University, Jupiter, FL, USA
| | - Rania M Katamish
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA
| | - Rodeania Peart
- Wilkes Honors College, Florida Atlantic University, Jupiter, FL, USA
| | - Samantha E Stilley
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA
| | - Keeley Spiess
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA
| | - Maximilian J Rabil
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA
| | | | - Angelica E Wiggins
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA
| | - Roxanne A Vaughan
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Maureen K Hahn
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA.,Stiles-Nicholson Brain Institute, Florida Atlantic University, Jupiter, FL, USA
| | - Randy D Blakely
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA. .,Stiles-Nicholson Brain Institute, Florida Atlantic University, Jupiter, FL, USA.
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9
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Clauss NJ, Owens WA, Vitela M, Bowman MA, Mayer FP, Schmid D, Holy M, Sitte HH, Gould GG, Koek W, Daws LC. Ethanol Inhibits Dopamine Uptake and Augments Rewarding Effects of Cocaine via Organic Cation Transporter 3. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r5274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Nikki J. Clauss
- Cellular and Integrative PhysiologyUniversity of Texas Health Science Center At San AntonioSan AntonioTX
| | - W. A. Owens
- Cellular and Integrative PhysiologyUniversity of Texas Health Science Center At San AntonioSan AntonioTX
| | - Melissa Vitela
- Cellular and Integrative PhysiologyUniversity of Texas Health Science Center At San AntonioSan AntonioTX
| | - Melodi A. Bowman
- Cellular and Integrative PhysiologyUniversity of Texas Health Science Center At San AntonioSan AntonioTX
| | - Felix P. Mayer
- Institute of PharmacologyMedical University of ViennaVienna
- Medical University of ViennaVienna
| | | | - Marion Holy
- Institute of PharmacologyMedical University of ViennaVienna
| | | | - Geogianna G. Gould
- Cellular and Integrative PhysiologyUniversity of Texas Health Science Center At San AntonioSan AntonioTX
| | - Wouter Koek
- Cellular and Integrative PhysiologyUniversity of Texas Health Science Center At San AntonioSan AntonioTX
| | - Lynette C. Daws
- Cellular and Integrative PhysiologyUniversity of Texas Health Science Center At San AntonioSan AntonioTX
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10
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Nawaratne V, McLaughlin SP, Mayer FP, Gichi Z, Mastriano A, Carvelli L. Prolonged Amphetamine Exposures Increase the Endogenous Human Dopamine Receptors 2 at the Cellular Membrane in Cells Lacking the Dopamine Transporter. Front Cell Neurosci 2021; 15:681539. [PMID: 34512264 PMCID: PMC8427050 DOI: 10.3389/fncel.2021.681539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 08/03/2021] [Indexed: 11/30/2022] Open
Abstract
The dopamine 2 receptors (D2R) are G-protein coupled receptors expressed both in pre- and post-synaptic terminals that play an important role in mediating the physiological and behavioral effects of amphetamine (Amph). Previous studies have indicated that the effects of Amph at the D2R mainly rely on the ability of Amph to robustly increase extracellular dopamine through the dopamine transporter (DAT). This implies that the effects of Amph on D2R require the neurotransmitter dopamine. However, because of its lipophilic nature, Amph can cross the cellular membrane and thus potentially affect D2R expression independently of dopamine and DAT, e.g., in post-synaptic terminals. Here we used an in vitro system to study whether Amph affects total expression, cellular distribution, and function of the human D2R (hD2R), endogenously expressed in HEK293 cells. By performing Western blot experiments, we found that prolonged treatments with 1 or 50 μM Amph cause a significant decrease of the endogenous hD2R in cells transfected with human DAT (hDAT). On the other hand, in cells lacking expression of DAT, quantification of the hD2R-mediated changes in cAMP, biotinylation assays, Western blots and imaging experiments demonstrated an increase of hD2R at the cellular membrane after 15-h treatments with Amph. Moreover, imaging data suggested that barbadin, a specific inhibitor of the βarrestin-βadaptin interaction, blocked the Amph-induced increase of hD2R. Taken together our data suggest that prolonged exposures to Amph decrease or increase the endogenous hD2R at the cellular membrane in HEK293 cells expressing or lacking hDAT, respectively. Considering that this drug is often consumed for prolonged periods, during which tolerance develops, our data suggest that even in absence of DAT or dopamine, Amph can still alter D2R distribution and function.
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Affiliation(s)
- Vindhya Nawaratne
- Department of Biology, Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL, United States
| | - Sean P. McLaughlin
- Brain Institute, Florida Atlantic University, Jupiter, FL, United States
| | - Felix P. Mayer
- Brain Institute, Florida Atlantic University, Jupiter, FL, United States
| | - Zayna Gichi
- Brain Institute, Florida Atlantic University, Jupiter, FL, United States
| | - Alyssa Mastriano
- Department of Biology, Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL, United States
| | - Lucia Carvelli
- Department of Biology, Harriet L. Wilkes Honors College, Florida Atlantic University, Jupiter, FL, United States
- Brain Institute, Florida Atlantic University, Jupiter, FL, United States
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11
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Mayer FP, Iwamoto H, Hahn MK, Grumbar GJ, Stewart A, Li Y, Blakely RD. There's no place like home? Return to the home cage triggers dopamine release in the mouse nucleus accumbens. Neurochem Int 2021; 142:104894. [PMID: 33161093 PMCID: PMC7779706 DOI: 10.1016/j.neuint.2020.104894] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 10/27/2020] [Accepted: 10/28/2020] [Indexed: 10/23/2022]
Abstract
Various stimuli have been employed as reinforcers in preclinical rodent models to elucidate the underpinnings of reward at a molecular and circuit level, with the release of dopamine (DA) in the nucleus accumbens (NAc) as a well-replicated, physiological correlate. Many factors, however, including strain differences, sex, prior stress, and reinforcer administration protocols can influence reward responding and DA release. Although previous evidence indicates that access to the home cage can be an effective reinforcer in behavioral tasks, whether this simple environmental manipulation can trigger DA release in the NAc has not been demonstrated. Here, using fiber photometric recordings of in vivo NAc dopamine release from a genetically-encoded DA sensor, we show that the movement of animals from the home cage to a clear, polycarbonate recording chamber evokes little to no DA release following initial exposure whereas returning animals from the recording chamber to a clean, home-like cage or to the home cage robustly triggers the release of DA, comparable in size to that observed with a 10 mg/kg i.p. Cocaine injection in the recording chamber. Although DA release can be evoked in moving mice to a clean cage, this release was significantly augmented when moving animals from the clean cage to the home cage. Our data provide direct evidence that home cage return from a foreign environment results in a biochemical change consistent with that of a rewarding stimulus. This simple environmental manipulation provides a minimally invasive approach to study the reward circuitry underlying an ethologically relevant reinforcer, return to the safe confines of "home". The home cage - DA release paradigm may also represent a biomarker-driven paradigm for the evaluation of genetic and experiential events that underlie anhedonic states, characteristic of major mood disorders, and to present new opportunities to identify their treatments.
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Affiliation(s)
- Felix P Mayer
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA
| | - Hideki Iwamoto
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA; Brain Institute, Florida Atlantic University, Jupiter, FL, USA
| | - Maureen K Hahn
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA; Brain Institute, Florida Atlantic University, Jupiter, FL, USA
| | - Gregory J Grumbar
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA
| | - Adele Stewart
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA; Brain Institute, Florida Atlantic University, Jupiter, FL, USA
| | - Yulong Li
- Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing, 100871, China
| | - Randy D Blakely
- Department of Biomedical Science, Florida Atlantic University, Jupiter, FL, USA; Brain Institute, Florida Atlantic University, Jupiter, FL, USA.
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12
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Mayer FP, Schmid D, Owens WA, Gould GG, Apuschkin M, Kudlacek O, Salzer I, Boehm S, Chiba P, Williams PH, Wu HH, Gether U, Koek W, Daws LC, Sitte HH. An unsuspected role for organic cation transporter 3 in the actions of amphetamine. Neuropsychopharmacology 2018; 43:2408-2417. [PMID: 29773909 PMCID: PMC6180071 DOI: 10.1038/s41386-018-0053-5] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 03/19/2018] [Accepted: 03/21/2018] [Indexed: 01/11/2023]
Abstract
Amphetamine abuse is a major public health concern for which there is currently no effective treatment. To develop effective treatments, the mechanisms by which amphetamine produces its abuse-related effects need to be fully understood. It is well known that amphetamine exerts its actions by targeting high-affinity transporters for monoamines, in particular the cocaine-sensitive dopamine transporter. Organic cation transporter 3 (OCT3) has recently been found to play an important role in regulating monoamine signaling. However, whether OCT3 contributes to the actions of amphetamine is unclear. We found that OCT3 is expressed in dopamine neurons. Then, applying a combination of in vivo, ex vivo, and in vitro approaches, we revealed that a substantial component of amphetamine's actions is OCT3-dependent and cocaine insensitive. Our findings support OCT3 as a new player in the actions of amphetamine and encourage investigation of this transporter as a potential new target for the treatment of psychostimulant abuse.
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Affiliation(s)
- Felix P. Mayer
- 0000 0000 9259 8492grid.22937.3dCenter for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - Diethart Schmid
- 0000 0000 9259 8492grid.22937.3dCenter for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - W. Anthony Owens
- 0000 0001 0629 5880grid.267309.9Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229 USA
| | - Georgianna G. Gould
- 0000 0001 0629 5880grid.267309.9Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229 USA
| | - Mia Apuschkin
- 0000 0001 0674 042Xgrid.5254.6Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Panum Institute 18.6, 2200 Copenhagen N, Denmark
| | - Oliver Kudlacek
- 0000 0000 9259 8492grid.22937.3dCenter for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - Isabella Salzer
- 0000 0000 9259 8492grid.22937.3dCenter for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - Stefan Boehm
- 0000 0000 9259 8492grid.22937.3dCenter for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - Peter Chiba
- 0000 0000 9259 8492grid.22937.3dInstitute of Medical Chemistry, Medical University of Vienna, 1090 Vienna, Austria
| | - Piper H. Williams
- 0000 0001 2156 6853grid.42505.36Department of Pediatrics, The Saban Research Institute, Children’s Hospital Los Angeles, Keck School of Medicine of USC, 4661 Sunset Blvd. Rm 307, Los Angeles, CA 90027 USA
| | - Hsiao-Huei Wu
- 0000 0001 2156 6853grid.42505.36Department of Pediatrics, The Saban Research Institute, Children’s Hospital Los Angeles, Keck School of Medicine of USC, 4661 Sunset Blvd. Rm 307, Los Angeles, CA 90027 USA
| | - Ulrik Gether
- 0000 0001 0674 042Xgrid.5254.6Molecular Neuropharmacology and Genetics Laboratory, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Panum Institute 18.6, 2200 Copenhagen N, Denmark
| | - Wouter Koek
- 0000 0001 0629 5880grid.267309.9Department of Psychiatry, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229 USA ,0000 0001 0629 5880grid.267309.9Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229 USA
| | - Lynette C. Daws
- 0000 0001 0629 5880grid.267309.9Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229 USA ,0000 0001 0629 5880grid.267309.9Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229 USA
| | - Harald H. Sitte
- 0000 0000 9259 8492grid.22937.3dCenter for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria ,0000 0000 9259 8492grid.22937.3dCenter for Addiction Research and Science, Medical University Vienna, Waehringerstrasse 13 A, 1090 Vienna, Austria
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13
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Fraser-Spears R, Krause-Heuer AM, Basiouny M, Mayer FP, Manishimwe R, Wyatt NA, Dobrowolski JC, Roberts MP, Greguric I, Kumar N, Koek W, Sitte HH, Callaghan PD, Fraser BH, Daws LC. Comparative analysis of novel decynium-22 analogs to inhibit transport by the low-affinity, high-capacity monoamine transporters, organic cation transporters 2 and 3, and plasma membrane monoamine transporter. Eur J Pharmacol 2018; 842:351-364. [PMID: 30473490 DOI: 10.1016/j.ejphar.2018.10.028] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 10/03/2018] [Accepted: 10/19/2018] [Indexed: 11/30/2022]
Abstract
Growing evidence supports involvement of low-affinity/high-capacity organic cation transporters (OCTs) and plasma membrane monoamine transporter (PMAT) in regulating clearance of monoamines. Currently decynium-22 (D22) is the best pharmacological tool to study these transporters, however it does not readily discriminate among them, underscoring a need to develop compounds with greater selectivity for each of these transporters. We developed seven D22 analogs, and previously reported that some have lower affinity for α1-adrenoceptors than D22 and showed antidepressant-like activity in mice. Here, we extend these findings to determine the affinity of these analogs for OCT2, OCT3 and PMAT, as well as serotonin, norepinephrine and dopamine transporters (SERT, NET and DAT) using a combination of uptake competition with [3H]methyl-4-phenylpyridinium acetate in overexpressed HEK cells and [3H]citalopram, [3H]nisoxetine and [3H]WIN 35428 displacement binding in mouse hippocampal and striatal preparations. Like D22, all analogs showed greater binding affinities for OCT3 than OCT2 and PMAT. However, unlike D22, some analogs also showed modest affinity for SERT and DAT. Dual OCT3/SERT and/or OCT3/DAT actions of certain analogs may help explain their ability to produce antidepressant-like effects in mice and help account for our previous findings that D22 lacks antidepressant-like effects unless SERT function is either genetically or pharmacologically compromised. Though these analogs are not superior than D22 in discriminating among OCTs/PMAT, our findings point to development of compounds with combined ability to inhibit both low-affinity/high-capacity transporters, such as OCT3, and high-affinity/low-capacity transporters, such as SERT, as therapeutics with potentially improved efficacy for treatment of psychiatric disorders.
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Affiliation(s)
- Rheaclare Fraser-Spears
- Department of Cellular & Integrative Physiology, University of Texas Health Science Center at San Antonio, United States; University of the Incarnate Word, Feik School of Pharmacy, Department of Pharmaceutical Sciences, United States
| | - Anwen M Krause-Heuer
- The Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Mohamed Basiouny
- Department of Cellular & Integrative Physiology, University of Texas Health Science Center at San Antonio, United States
| | - Felix P Mayer
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Währingerstraße 13A, 1090 Vienna, Austria
| | - Retrouvailles Manishimwe
- Department of Cellular & Integrative Physiology, University of Texas Health Science Center at San Antonio, United States
| | - Naomi A Wyatt
- The Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | | | - Maxine P Roberts
- The Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Ivan Greguric
- The Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Naresh Kumar
- University of New South Wales, School of Chemistry, Sydney, NSW 2052, Australia
| | - Wouter Koek
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, United States; Department of Psychiatry, University of Texas Health Science Center at San Antonio, United States
| | - Harald H Sitte
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Währingerstraße 13A, 1090 Vienna, Austria
| | - Paul D Callaghan
- The Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Benjamin H Fraser
- The Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, NSW 2232, Australia
| | - Lynette C Daws
- Department of Cellular & Integrative Physiology, University of Texas Health Science Center at San Antonio, United States; Department of Pharmacology, University of Texas Health Science Center at San Antonio, United States.
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14
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Abstract
Aminorex (5-phenyl-4,5-dihydro-1,3-oxazol-2-amine) and 4-methylaminorex (4-methyl-5-phenyl-4,5-dihydro-1,3-oxazol-2-amine) are psychostimulants that have long been listed in Schedules IV and I of the UN Convention on Psychotropic Substances of 1971. However, a range of psychoactive analogues exist that are not internationally controlled and therefore often classified as new psychoactive substances (NPS). Aminorex analogues encompass failed pharmaceuticals that reemerged as drugs of abuse, and newly synthesized substances that were solely designed for recreational use by clandestine chemists. NPS, sometimes also referred to as "designer drugs" in alignment with a phenomenon arising in the early 1980s, serve as alternatives to controlled drugs. Aminorex and its derivatives interact with monoaminergic neurotransmission by interfering with the function of monoamine transporters. Hence, these compounds share pharmacological and neurochemical similarities with amphetamines and cocaine. The consumption of aminorex, 4-methylaminorex and 4,4'-dimethylaminorex (4-methyl-5-(4-methylphenyl)-4,5-dihydro-1,3-oxazol-2-amine) has been associated with adverse events including death, bestowing an inglorious fame on aminorex-derived drugs. In this Review, a historical background is presented, as well as an account of the pharmacodynamic and pharmacokinetic properties of aminorex and various analogues. Light is shed on their misuse as drug adulterants of well-established drugs on the market. This Review not only provides a detailed overview of an abused substance-class, but also emphasizes the darkest aspect of the NPS market, i.e., deleterious side effects that arise from the ingestion of certain NPS, as knowledge of the pharmacology, the potency, or the identity of the active ingredients remains obscure to NPS users.
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Affiliation(s)
- Julian Maier
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Währingerstraße 13A, 1090, Vienna, Austria
| | - Felix P. Mayer
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Währingerstraße 13A, 1090, Vienna, Austria
| | - Simon D. Brandt
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Harald H. Sitte
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Währingerstraße 13A, 1090, Vienna, Austria
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15
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Maier J, Mayer FP, Luethi D, Holy M, Jäntsch K, Reither H, Hirtler L, Hoener MC, Liechti ME, Pifl C, Brandt SD, Sitte HH. The psychostimulant (±)-cis-4,4'-dimethylaminorex (4,4'-DMAR) interacts with human plasmalemmal and vesicular monoamine transporters. Neuropharmacology 2018; 138:282-291. [PMID: 29908239 DOI: 10.1016/j.neuropharm.2018.06.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 05/01/2018] [Accepted: 06/12/2018] [Indexed: 10/28/2022]
Abstract
(±)-cis-4,4'-Dimethylaminorex (4,4'-DMAR) is a new psychoactive substance (NPS) that has been associated with 31 fatalities and other adverse events in Europe between June 2013 and February 2014. We used in vitro uptake inhibition and transporter release assays to determine the effects of 4,4'-DMAR on human high-affinity transporters for dopamine (DAT), norepinephrine (NET) and serotonin (SERT). In addition, we assessed its binding affinities to monoamine receptors and transporters. Furthermore, we investigated the interaction of 4,4'-DMAR with the vesicular monoamine transporter 2 (VMAT2) in rat phaeochromocytoma (PC12) cells and synaptic vesicles prepared from human striatum. 4,4'-DMAR inhibited uptake mediated by human DAT, NET or SERT, respectively in the low micromolar range (IC50 values < 2 μM). Release assays identified 4,4'-DMAR as a substrate type releaser, capable of inducing transporter-mediated reverse transport via DAT, NET and SERT. Furthermore, 4,4'-DMAR inhibited both the rat and human isoforms of VMAT2 at a potency similar to 3,4-methylenedioxymethylamphetamine (MDMA). This study identified 4,4'-DMAR as a potent non-selective monoamine releasing agent. In contrast to the known effects of aminorex and 4-methylaminorex, 4,4'-DMAR exerts profound effects on human SERT. The latter finding is consistent with the idea that fatalities associated with its abuse may be linked to monoaminergic toxicity including serotonin syndrome. The activity at VMAT2 suggests that chronic abuse of 4,4'-DMAR may result in long-term neurotoxicity.
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Affiliation(s)
- Julian Maier
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Währingerstraße 13A, 1090, Vienna, Austria
| | - Felix P Mayer
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Währingerstraße 13A, 1090, Vienna, Austria
| | - Dino Luethi
- University Hospital Basel and University of Basel, Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, Hebelstraße 20, 4031, Basel, Switzerland
| | - Marion Holy
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Währingerstraße 13A, 1090, Vienna, Austria
| | - Kathrin Jäntsch
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Währingerstraße 13A, 1090, Vienna, Austria
| | - Harald Reither
- Medical University of Vienna, Center for Brain Research, Department of Molecular Neurosciences, Spitalgasse 4, 1090, Vienna, Austria
| | - Lena Hirtler
- Medical University of Vienna, Center for Anatomy and Cell Biology, Währingerstraße 13, 1090, Vienna, Austria
| | - Marius C Hoener
- F. Hoffmann - La Roche Ltd., pRED, Roche Innovation Center Basel, Neuroscience Research, Department of Neurosymptomatic Domains, Grenzacherstraße 124, 4070, Basel, Switzerland
| | - Matthias E Liechti
- University Hospital Basel and University of Basel, Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, Hebelstraße 20, 4031, Basel, Switzerland
| | - Christian Pifl
- Medical University of Vienna, Center for Brain Research, Department of Molecular Neurosciences, Spitalgasse 4, 1090, Vienna, Austria
| | - Simon D Brandt
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Harald H Sitte
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Währingerstraße 13A, 1090, Vienna, Austria; Center for Addiction Research and Science, Medical University Vienna, Waehringerstrasse 13A, 1090 Vienna, Austria.
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16
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Hasenhuetl PS, Bhat S, Mayer FP, Sitte HH, Freissmuth M, Sandtner W. A kinetic account for amphetamine-induced monoamine release. J Gen Physiol 2018; 150:431-451. [PMID: 29439119 PMCID: PMC5839721 DOI: 10.1085/jgp.201711915] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 01/18/2018] [Indexed: 01/14/2023] Open
Abstract
This study on serotonin transporters shows that amphetamine-induced monoamine release requires cooperative substrate and cosubstrate binding. A kinetic model is presented that can account qualitatively and quantitatively for the releasing action of amphetamines. The plasmalemmal monoamine transporters for dopamine, norepinephrine, and serotonin (SERT) are targets for amphetamines. In vivo, amphetamines elicit most, if not all, of their actions by triggering monoamine efflux. This is thought to be accomplished by an amphetamine-induced switch from the forward-transport to the substrate-exchange mode. The mechanism underlying this switch has remained elusive; available kinetic models posit that substrates and cosubstrate Na+ ions bind either in a random or in a sequential order. Neither can account for all reported experimental observations. We used electrophysiological recordings to interrogate crucial conformational transitions associated with the binding of five different substrates (serotonin, para-chloroamphetamine, and the high-affinity naphthyl-propan-amines PAL-287, PAL-1045, and PAL-1046) to human SERT expressed in HEK293 cells; specifically, we determined the relaxation kinetics of SERT from a substrate-loaded to a substrate-free state at various intracellular and extracellular Na+ concentrations. These rates and their dependence on intracellular and extracellular Na+ concentrations differed considerably between substrates. We also examined the effect of K+ on substrate affinity and found that K+ enhanced substrate dissociation. A kinetic model was developed, which allowed for random, but cooperative, binding of substrate and Na+ (or K+). The synthetic data generated by this model recapitulated the experimental observations. More importantly, the cooperative binding model accounted for the releasing action of amphetamines without any digression from alternating access. To the best of our knowledge, this model is the first to provide a mechanistic framework for amphetamine-induced monoamine release and to account for the findings that some substrates are less efficacious than others in promoting the substrate-exchange mode.
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Affiliation(s)
- Peter S Hasenhuetl
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Shreyas Bhat
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Felix P Mayer
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Harald H Sitte
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Michael Freissmuth
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Walter Sandtner
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
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17
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Mayer FP, Luf A, Nagy C, Holy M, Schmid R, Freissmuth M, Sitte HH. Application of a Combined Approach to Identify New Psychoactive Street Drugs and Decipher Their Mechanisms at Monoamine Transporters. Curr Top Behav Neurosci 2017; 32:333-350. [PMID: 28025810 DOI: 10.1007/7854_2016_63] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Psychoactive compounds can cause acute and long-term health problems and lead to addiction. In addition to well-studied and legally controlled compounds like cocaine, new psychoactive substances (NPS) are appearing in street drug markets as replacement strategies and legal alternatives. NPS are effectively marketed as "designer drugs" or "research chemicals" without any knowledge of their underlying pharmacological mode of action and their potential toxicological effects and obviously devoid of any registration process. As of 2016, the knowledge of structure-activity relationships for most NPS is scarce, and predicting detailed pharmacological activity of newly emerging drugs is a challenging task. Therefore, it is important to combine different approaches and employ biological test systems that are superior to mere chemical analysis in recognizing novel and potentially harmful street drugs. In this chapter, we provide a detailed description of techniques to decipher the molecular mechanism of action of NPS that target the high-affinity transporters for dopamine, norepinephrine, and serotonin. In addition, this chapter provides insights into a combined approach to identify and characterize new psychoactive street drugs of unknown content in a collaboration with the Austrian prevention project "checkit!."
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Affiliation(s)
- Felix P Mayer
- Center of Physiology and Pharmacology, Institute of Pharmacology, Medical University Vienna, Waehringerstrasse 13a, A-1090, Vienna, Austria
| | - Anton Luf
- Clinical Department of Laboratory Medicine, Medical University of Vienna, Waehringer Guertel 10-20, 1090, Vienna, Austria
| | - Constanze Nagy
- checkit! - Suchthilfe Wien GmbH, Gumpendorfer Gürtel 8, 1060, Vienna, Austria
| | - Marion Holy
- Center of Physiology and Pharmacology, Institute of Pharmacology, Medical University Vienna, Waehringerstrasse 13a, A-1090, Vienna, Austria
| | - Rainer Schmid
- Clinical Department of Laboratory Medicine, Medical University of Vienna, Waehringer Guertel 10-20, 1090, Vienna, Austria
| | - Michael Freissmuth
- Center of Physiology and Pharmacology, Institute of Pharmacology, Medical University Vienna, Waehringerstrasse 13a, A-1090, Vienna, Austria
| | - Harald H Sitte
- Center of Physiology and Pharmacology, Institute of Pharmacology, Medical University Vienna, Waehringerstrasse 13a, A-1090, Vienna, Austria.
- Center for Addiction Research and Science - Medical University Vienna, Waehringerstrasse 13A, 1090, Vienna, Austria.
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Kudlacek O, Hofmaier T, Luf A, Mayer FP, Stockner T, Nagy C, Holy M, Freissmuth M, Schmid R, Sitte HH. Cocaine adulteration. J Chem Neuroanat 2017; 83-84:75-81. [PMID: 28619473 DOI: 10.1016/j.jchemneu.2017.06.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 05/03/2017] [Accepted: 06/10/2017] [Indexed: 12/20/2022]
Abstract
Cocaine is a naturally occurring and illicitly used psychostimulant drug. Cocaine acts at monoaminergic neurotransmitter transporters to block uptake of the monoamines, dopamine, serotonin and norepinephrine. The resulting increase of monoamines in the extracellular space underlies the positively reinforcing effects that cocaine users seek. In turn, this increase in monoamines underlies the development of addiction, and can also result in a number of severe side effects. Currently, cocaine is one of the most common illicit drugs available on the European market. However, cocaine is increasingly sold in impure forms. This trend is driven by cocaine dealers seeking to increase their profit margin by mixing ("cutting") cocaine with numerous other compounds ("adulterants"). Importantly, these undeclared compounds put cocaine consumers at risk, because consumers are not aware of the additional potential threats to their health. This review describes adulterants that have been identified in cocaine sold on the street market. Their typical pharmacological profile and possible reasons why these compounds can be used as cutting agents will be discussed. Since a subset of these adulterants has been found to exert effects similar to cocaine itself, we will discuss levamisole, the most frequently used cocaine cutting agent today, and its metabolite aminorex.
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Affiliation(s)
- Oliver Kudlacek
- Medical University Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Waehringerstrasse 13a, 1090 Vienna, Austria
| | - Tina Hofmaier
- Medical University Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Waehringerstrasse 13a, 1090 Vienna, Austria
| | - Anton Luf
- Medical University of Vienna, Clinical Department of Laboratory Medicine, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - Felix P Mayer
- Medical University Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Waehringerstrasse 13a, 1090 Vienna, Austria
| | - Thomas Stockner
- Medical University Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Waehringerstrasse 13a, 1090 Vienna, Austria
| | - Constanze Nagy
- checkit!-Suchthilfe Wien gGmbH, Gumpendorferstraße8, 1060 Vienna, Austria
| | - Marion Holy
- Medical University Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Waehringerstrasse 13a, 1090 Vienna, Austria
| | - Michael Freissmuth
- Medical University Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Waehringerstrasse 13a, 1090 Vienna, Austria
| | - Rainer Schmid
- Medical University of Vienna, Clinical Department of Laboratory Medicine, Waehringer Guertel 18-20, 1090 Vienna, Austria
| | - Harald H Sitte
- Medical University Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Waehringerstrasse 13a, 1090 Vienna, Austria; Center for Addiction Research and Science - Medical University Vienna, Waehringerstrasse 13A, 1090 Vienna, Austria.
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Li Y, Mayer FP, Hasenhuetl PS, Burtscher V, Schicker K, Sitte HH, Freissmuth M, Sandtner W. Occupancy of the zinc-binding site by transition metals decreases the substrate affinity of the human dopamine transporter by an allosteric mechanism. J Biol Chem 2017; 292:7161. [PMID: 28455408 PMCID: PMC5409482 DOI: 10.1074/jbc.a116.760140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Li Y, Mayer FP, Hasenhuetl PS, Burtscher V, Schicker K, Sitte HH, Freissmuth M, Sandtner W. Occupancy of the Zinc-binding Site by Transition Metals Decreases the Substrate Affinity of the Human Dopamine Transporter by an Allosteric Mechanism. J Biol Chem 2017; 292:4235-4243. [PMID: 28096460 PMCID: PMC5354487 DOI: 10.1074/jbc.m116.760140] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 12/16/2016] [Indexed: 11/06/2022] Open
Abstract
The human dopamine transporter (DAT) has a tetrahedral Zn2+-binding site. Zn2+-binding sites are also recognized by other first-row transition metals. Excessive accumulation of manganese or of copper can lead to parkinsonism because of dopamine deficiency. Accordingly, we examined the effect of Mn2+, Co2+, Ni2+, and Cu2+ on transport-associated currents through DAT and DAT-H193K, a mutant with a disrupted Zn2+-binding site. All transition metals except Mn2+ modulated the transport cycle of wild-type DAT with affinities in the low micromolar range. In this concentration range, they were devoid of any action on DAT-H193K. The active transition metals reduced the affinity of DAT for dopamine. The affinity shift was most pronounced for Cu2+, followed by Ni2+ and Zn2+ (= Co2+). The extent of the affinity shift and the reciprocal effect of substrate on metal affinity accounted for the different modes of action: Ni2+ and Cu2+ uniformly stimulated and inhibited, respectively, the substrate-induced steady-state currents through DAT. In contrast, Zn2+ elicited biphasic effects on transport, i.e. stimulation at 1 μm and inhibition at 10 μm. A kinetic model that posited preferential binding of transition metal ions to the outward-facing apo state of DAT and a reciprocal interaction of dopamine and transition metals recapitulated all experimental findings. Allosteric activation of DAT via the Zn2+-binding site may be of interest to restore transport in loss-of-function mutants.
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Affiliation(s)
- Yang Li
- From the Institute of Pharmacology, Center of Physiology and Pharmacology, Medical University Vienna, Waehringerstrasse 13a, 1090 Vienna, Austria
| | - Felix P Mayer
- From the Institute of Pharmacology, Center of Physiology and Pharmacology, Medical University Vienna, Waehringerstrasse 13a, 1090 Vienna, Austria
| | - Peter S Hasenhuetl
- From the Institute of Pharmacology, Center of Physiology and Pharmacology, Medical University Vienna, Waehringerstrasse 13a, 1090 Vienna, Austria
| | - Verena Burtscher
- From the Institute of Pharmacology, Center of Physiology and Pharmacology, Medical University Vienna, Waehringerstrasse 13a, 1090 Vienna, Austria
| | - Klaus Schicker
- From the Institute of Pharmacology, Center of Physiology and Pharmacology, Medical University Vienna, Waehringerstrasse 13a, 1090 Vienna, Austria
| | - Harald H Sitte
- From the Institute of Pharmacology, Center of Physiology and Pharmacology, Medical University Vienna, Waehringerstrasse 13a, 1090 Vienna, Austria
| | - Michael Freissmuth
- From the Institute of Pharmacology, Center of Physiology and Pharmacology, Medical University Vienna, Waehringerstrasse 13a, 1090 Vienna, Austria
| | - Walter Sandtner
- From the Institute of Pharmacology, Center of Physiology and Pharmacology, Medical University Vienna, Waehringerstrasse 13a, 1090 Vienna, Austria
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Mayer FP, Wimmer L, Dillon-Carter O, Partilla JS, Burchardt NV, Mihovilovic MD, Baumann MH, Sitte HH. Phase I metabolites of mephedrone display biological activity as substrates at monoamine transporters. Br J Pharmacol 2016; 173:2657-68. [PMID: 27391165 PMCID: PMC4978154 DOI: 10.1111/bph.13547] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 05/30/2016] [Accepted: 06/26/2016] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND AND PURPOSE 4-Methyl-N-methylcathinone (mephedrone) is a synthetic stimulant that acts as a substrate-type releaser at transporters for dopamine (DAT), noradrenaline (NET) and 5-HT (SERT). Upon systemic administration, mephedrone is metabolized to several phase I compounds: the N-demethylated metabolite, 4-methylcathinone (nor-mephedrone); the ring-hydroxylated metabolite, 4-hydroxytolylmephedrone (4-OH-mephedrone); and the reduced keto-metabolite, dihydromephedrone. EXPERIMENTAL APPROACH We used in vitro assays to compare the effects of mephedrone and synthetically prepared metabolites on transporter-mediated uptake and release in HEK293 cells expressing human monoamine transporters and in rat brain synaptosomes. In vivo microdialysis was employed to examine the effects of i.v. metabolite injection (1 and 3 mg·kg(-1) ) on extracellular dopamine and 5-HT levels in rat nucleus accumbens. KEY RESULTS In cells expressing transporters, mephedrone and its metabolites inhibited uptake, although dihydromephedrone was weak overall. In cells and synaptosomes, nor-mephedrone and 4-OH-mephedrone served as transportable substrates, inducing release via monoamine transporters. When administered to rats, mephedrone and nor-mephedrone produced elevations in extracellular dopamine and 5-HT, whereas 4-OH-mephedrone did not. Mephedrone and nor-mephedrone, but not 4-OH-mephedrone, induced locomotor activity. CONCLUSIONS AND IMPLICATIONS Our results demonstrate that phase I metabolites of mephedrone are transporter substrates (i.e. releasers) at DAT, NET and SERT, but dihydromephedrone is weak in this regard. When administered in vivo, nor-mephedrone increases extracellular dopamine and 5-HT in the brain whereas 4-OH-mephedrone does not, suggesting the latter metabolite does not penetrate the blood-brain barrier. Future studies should examine the pharmacokinetics of nor-mephedrone to determine its possible contribution to the in vivo effects produced by mephedrone.
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Affiliation(s)
- F P Mayer
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Vienna, Austria
| | - L Wimmer
- Institute of Applied Synthetic Chemistry, Vienna University of Technology, Vienna, Austria
| | - O Dillon-Carter
- Designer Drug Research Unit (DDRU), Intramural Research Program (IRP), NIDA, NIH, Baltimore, MD, USA
| | - J S Partilla
- Designer Drug Research Unit (DDRU), Intramural Research Program (IRP), NIDA, NIH, Baltimore, MD, USA
| | - N V Burchardt
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Vienna, Austria
| | - M D Mihovilovic
- Institute of Applied Synthetic Chemistry, Vienna University of Technology, Vienna, Austria
| | - M H Baumann
- Designer Drug Research Unit (DDRU), Intramural Research Program (IRP), NIDA, NIH, Baltimore, MD, USA
| | - H H Sitte
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Vienna, Austria
- Center for Addiction Research and Science, Medical University Vienna, Vienna, Austria
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Sandtner W, Schmid D, Schicker K, Gerstbrein K, Koenig X, Mayer FP, Boehm S, Freissmuth M, Sitte HH. A quantitative model of amphetamine action on the 5-HT transporter. Br J Pharmacol 2014; 171:1007-18. [PMID: 24251585 PMCID: PMC3925039 DOI: 10.1111/bph.12520] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 10/30/2013] [Accepted: 11/05/2013] [Indexed: 10/27/2022] Open
Abstract
BACKGROUND AND PURPOSE Amphetamines bind to the plasmalemmal transporters for the monoamines dopamine (DAT), noradrenaline (NET) and 5-HT (SERT); influx of amphetamine leads to efflux of substrates. Various models have been proposed to account for this amphetamine-induced reverse transport in mechanistic terms. A most notable example is the molecular stent hypothesis, which posits a special amphetamine-induced conformation that is not likely in alternative access models of transport. The current study was designed to evaluate the explanatory power of these models and the molecular stent hypothesis. EXPERIMENTAL APPROACH Xenopus laevis oocytes and HEK293 cells expressing human (h) SERT were voltage-clamped and exposed to 5-HT, p-chloroamphetamine (pCA) or methylenedioxyamphetamine (MDMA). KEY RESULTS In contrast to the currents induced by 5-HT, pCA-triggered currents through SERT decayed slowly in Xenopus laevis oocytes once the agonist was removed (consistent with the molecular stent hypothesis). However, when SERT was expressed in HEK293 cells, currents induced by 3 or 100 μM pCA decayed 10 or 100 times faster, respectively, after pCA removal. CONCLUSIONS AND IMPLICATIONS This discrepancy in decay rates is inconsistent with the molecular stent hypothesis. In contrast, a multistate version of the alternative access model accounts for all the observations and reproduces the kinetic parameters extracted from the electrophysiological recordings. A crucial feature that explains the action of amphetamines is their lipophilic nature, which allows for rapid diffusion through the membrane.
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Affiliation(s)
- Walter Sandtner
- Center of Physiology and Pharmacology, Medical University Vienna, Vienna, Austria
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Mayer FP, Schmid D, Holy M, Yang JW, Salzer I, Boehm S, Chiba P, Sitte HH. Real-time uptake of fluorescent ASP+ via the organic cation transporter 3. BMC Pharmacol Toxicol 2012. [PMCID: PMC3506348 DOI: 10.1186/2050-6511-13-s1-a80] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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