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Lu J, Huang G, Chang X, Wei B, Sun Y, Yang Z, Zhao Y, Zhao Z, Dong G, Chen J. Effects of Serotonin on Cell Viability, Permeability of Bovine Mammary Gland Epithelial Cells and Their Transcriptome Analysis. Int J Mol Sci 2023; 24:11388. [PMID: 37511146 PMCID: PMC10379418 DOI: 10.3390/ijms241411388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 07/10/2023] [Accepted: 07/11/2023] [Indexed: 07/30/2023] Open
Abstract
Serotonin (5-HT) has been reported to play an important role in mammary gland involution that is defined as the process through which the gland returns to a nonlactating state. However, the overall picture of the regulatory mechanisms of 5-HT and the effects of serotonylation on mammary gland involution still need to be further investigated. The current study aimed to investigate the effects of 5-HT on global gene expression profiles of bovine mammary epithelial cells (MAC-T) and to preliminarily examine whether the serotonylation involved in the mammary gland involution by using Monodansylcadaverine (MDC), a competitive inhibitor of transglutaminase 2. Results showed that a high concentration of 5-HT decreased viability and transepithelial electrical resistance (TEER) in MAC-T cells. Transcriptome analysis indicated that 2477 genes were differentially expressed in MAC-T cells treated with 200 μg/mL of 5-HT compared with the control group, and the Notch, p53, and PI3K-Akt signaling pathways were enriched. MDC influenced 5-HT-induced MAC-T cell death, fatty acid synthesis, and the formation and disruption of tight junctions. Overall, a high concentration of 5-HT is able to accelerate mammary gland involution, which may be regulated through the Notch, p53, and PI3K-Akt signaling pathways. Serotonylation is involved in bovine mammary gland involution.
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Affiliation(s)
- Jie Lu
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
- Chongqing Key Laboratory of Herbivore Science, Chongqing 400715, China
| | - Guohao Huang
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
- Chongqing Key Laboratory of Herbivore Science, Chongqing 400715, China
| | - Xuan Chang
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
- Chongqing Key Laboratory of Herbivore Science, Chongqing 400715, China
| | - Bingni Wei
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
- Chongqing Key Laboratory of Herbivore Science, Chongqing 400715, China
| | - Yawang Sun
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
- Chongqing Key Laboratory of Herbivore Science, Chongqing 400715, China
| | - Zhengguo Yang
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
- Chongqing Key Laboratory of Herbivore Science, Chongqing 400715, China
| | - Yongju Zhao
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
- Chongqing Key Laboratory of Herbivore Science, Chongqing 400715, China
| | - Zhongquan Zhao
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
- Chongqing Key Laboratory of Herbivore Science, Chongqing 400715, China
| | - Guozhong Dong
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
- Chongqing Key Laboratory of Herbivore Science, Chongqing 400715, China
| | - Juncai Chen
- College of Animal Science and Technology, Southwest University, Chongqing 400715, China
- Chongqing Key Laboratory of Herbivore Science, Chongqing 400715, China
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Hjorth O, Frick A, Gingnell M, Engman J, Björkstrand J, Faria V, Alaie I, Carlbring P, Andersson G, Jonasson M, Lubberink M, Antoni G, Reis M, Wahlstedt K, Fredrikson M, Furmark T. Serotonin and dopamine transporter availability in social anxiety disorder after combined treatment with escitalopram and cognitive-behavioral therapy. Transl Psychiatry 2022; 12:436. [PMID: 36202797 PMCID: PMC9537299 DOI: 10.1038/s41398-022-02187-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 09/08/2022] [Accepted: 09/13/2022] [Indexed: 11/15/2022] Open
Abstract
Selective serotonin reuptake inhibitors (SSRIs) and internet-based cognitive behavioral therapy (ICBT) are recommended treatments of social anxiety disorder (SAD), and often combined, but their effects on monoaminergic signaling are not well understood. In this multi-tracer positron emission tomography (PET) study, 24 patients with SAD were randomized to treatment with escitalopram+ICBT or placebo+ICBT under double-blind conditions. Before and after 9 weeks of treatment, patients were examined with positron emission tomography and the radioligands [11C]DASB and [11C]PE2I, probing the serotonin (SERT) and dopamine (DAT) transporter proteins respectively. Both treatment combinations resulted in significant improvement as measured by the Liebowitz Social Anxiety Scale (LSAS). At baseline, SERT-DAT co-expression was high and, in the putamen and thalamus, co-expression showed positive associations with symptom severity. SERT-DAT co-expression was also predictive of treatment success, but predictor-outcome associations differed in direction between the treatments. After treatment, average SERT occupancy in the SSRI + ICBT group was >80%, with positive associations between symptom improvement and occupancy in the nucleus accumbens, putamen and anterior cingulate cortex. Following placebo+ICBT, SERT binding increased in the raphe nuclei. DAT binding increased in both groups in limbic and striatal areas, but relations with symptom improvement differed, being negative for SSRI + ICBT and positive for placebo + ICBT. Thus, serotonin-dopamine transporter co-expression exerts influence on symptom severity and remission rate in the treatment of social anxiety disorder. However, the monoamine transporters are modulated in dissimilar ways when cognitive-behavioral treatment is given concomitantly with either SSRI-medication or pill placebo.
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Affiliation(s)
- Olof Hjorth
- Department of Psychology, Uppsala University, Uppsala, Sweden.
| | - Andreas Frick
- grid.8993.b0000 0004 1936 9457Department of Psychology, Uppsala University, Uppsala, Sweden ,grid.8993.b0000 0004 1936 9457The Beijer Laboratory, Department of Medical Sciences, Psychiatry, Uppsala University, Uppsala, Sweden
| | - Malin Gingnell
- grid.8993.b0000 0004 1936 9457Department of Psychology, Uppsala University, Uppsala, Sweden ,grid.8993.b0000 0004 1936 9457Department of Medical Sciences, Psychiatry, Uppsala University, Uppsala, Sweden
| | - Jonas Engman
- grid.8993.b0000 0004 1936 9457Department of Psychology, Uppsala University, Uppsala, Sweden
| | - Johannes Björkstrand
- grid.4514.40000 0001 0930 2361Department of Psychology, Lund University, Lund, Sweden
| | - Vanda Faria
- grid.38142.3c000000041936754XCenter for Pain and the Brain, Department of Anesthesiology Perioperative and Pain Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, MA USA ,grid.4488.00000 0001 2111 7257Smell & Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Dresden, Germany
| | - Iman Alaie
- grid.8993.b0000 0004 1936 9457Department of Medical Sciences, Child and Adolescent Psychiatry, Uppsala University, Uppsala, Sweden
| | - Per Carlbring
- grid.10548.380000 0004 1936 9377Department of Psychology, Stockholm University, Stockholm, Sweden
| | - Gerhard Andersson
- grid.4714.60000 0004 1937 0626Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden ,grid.5640.70000 0001 2162 9922Department of Behavioural Sciences and Learning, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - My Jonasson
- grid.8993.b0000 0004 1936 9457Department of Surgical Sciences, Radiology, Uppsala University, Uppsala, Sweden
| | - Mark Lubberink
- grid.8993.b0000 0004 1936 9457Department of Surgical Sciences, Radiology, Uppsala University, Uppsala, Sweden
| | - Gunnar Antoni
- grid.8993.b0000 0004 1936 9457Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden
| | - Margareta Reis
- grid.5640.70000 0001 2162 9922Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Kurt Wahlstedt
- grid.8993.b0000 0004 1936 9457Department of Psychology, Uppsala University, Uppsala, Sweden
| | - Mats Fredrikson
- grid.8993.b0000 0004 1936 9457Department of Psychology, Uppsala University, Uppsala, Sweden ,grid.4714.60000 0004 1937 0626Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Tomas Furmark
- grid.8993.b0000 0004 1936 9457Department of Psychology, Uppsala University, Uppsala, Sweden
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Faster Serotonin Clearance in CA3 Region of Hippocampus and Antidepressant-like Effect of Decynium-22 in Juvenile Mice Are Putatively Linked to Increased Plasma Membrane Monoamine Transporter Function: Implications for Efficacy of Antidepressants in Juveniles. Cells 2022; 11:cells11152454. [PMID: 35954298 PMCID: PMC9368098 DOI: 10.3390/cells11152454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 08/02/2022] [Accepted: 08/04/2022] [Indexed: 11/17/2022] Open
Abstract
Selective serotonin reuptake inhibitors (SSRIs) are less efficacious in treating depression in children than in adults. SSRIs block serotonin uptake via the high-affinity, low-capacity serotonin transporter. However, the low-affinity, high-capacity organic cation transporter 3 (OCT3) and plasma membrane monoamine transporter (PMAT) are emerging as important players in serotonin uptake. We hypothesized that OCT3 and/or PMAT are functionally upregulated in juveniles, thereby buffering SSRIs' ability to enhance serotonergic neurotransmission. Unlike in adult mice, we found the OCT/PMAT blocker, decynium-22, to have standalone antidepressant-like effects in juveniles. Using in vivo high-speed chronoamperometry, we found that juveniles clear serotonin from the CA3 region of the hippocampus ~2-fold faster than adult mice. Cell density did not differ between ages, suggesting that faster serotonin clearance in juveniles is unrelated to faster diffusion through the extracellular matrix. Western blot and immunohistochemistry showed that juvenile mice have modestly greater expression of PMAT than adults, whereas OCT3 expression in the CA3 region of the hippocampus was similar between ages. Together, these data suggest that faster serotonin clearance and antidepressant-like effects of decynium-22 in juvenile mice may be due to functionally upregulated PMAT. Faster serotonin clearance via PMAT in juveniles may contribute to reduced therapeutic efficacy of SSRIs in children relative to adults.
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Reyes-Parada M, Iturriaga-Vasquez P, Cassels BK. Amphetamine Derivatives as Monoamine Oxidase Inhibitors. Front Pharmacol 2020; 10:1590. [PMID: 32038257 PMCID: PMC6989591 DOI: 10.3389/fphar.2019.01590] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Accepted: 12/09/2019] [Indexed: 12/11/2022] Open
Abstract
Amphetamine and its derivatives exhibit a wide range of pharmacological activities, including psychostimulant, hallucinogenic, entactogenic, anorectic, or antidepressant effects. The mechanisms of action underlying these effects are usually related to the ability of the different amphetamines to interact with diverse monoamine transporters or receptors. Moreover, many of these compounds are also potent and selective monoamine oxidase inhibitors. In the present work, we review how structural modifications on the aromatic ring, the amino group and/or the aliphatic side chain of the parent scaffold, modulate the enzyme inhibitory properties of hundreds of amphetamine derivatives. Furthermore, we discuss how monoamine oxidase inhibition might influence the pharmacology of these compounds.
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Affiliation(s)
- Miguel Reyes-Parada
- Centro de Investigación Biomédica y Aplicada (CIBAP), Escuela de Medicina, Facultad de Ciencias Médicas, Universidad de Santiago de Chile, Santiago, Chile.,Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Talca, Chile
| | - Patricio Iturriaga-Vasquez
- Departamento de Ciencias Químicas y Recursos Naturales, Facultad de Ingeniería y Ciencias, Universidad de la Frontera, Temuco, Chile
| | - Bruce K Cassels
- Departamento de Química, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
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Martín-López M, Muela AT, Cavas M, Navarro JF. Effects of para-methoxyamphetamine (PMA) on agonistic encounters between male mice. Pharmacol Biochem Behav 2018; 167:9-16. [PMID: 29453997 DOI: 10.1016/j.pbb.2018.02.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 02/09/2018] [Accepted: 02/12/2018] [Indexed: 11/30/2022]
Abstract
Para-methoxyamphetamine (PMA) is a synthetic drug chemically similar to the recreational drug 3,4-methylenedioxy-methamphetamine (MDMA or "ecstasy") and often replaces MDMA in tablets that show an "ecstasy" logo. PMA displays a higher toxic potential than MDMA, but the behavioral profile of PMA has been scarcely studied in animal models. Here we evaluated the effects of PMA (2, 4, 8, and 12 mg/kg, i.p.) on agonist encounters between male mice using an ethopharmacological approach, the isolation-induced aggression model. Likewise, since PMA and MDMA share common mechanisms of action, we compared the behavioral profile of PMA with that induced by MDMA (8 mg/kg, i.p.) which behavioral effects in this model are well characterized. Individually housed mice were exposed to anosmic standard opponents 30 min after drug administration. The encounters were videotaped and evaluated using an ethologically based analysis. PMA (all doses) significantly reduced offensive behaviors (threat and attack), however, a detailed behavioral analysis suggests that the observed antiaggressive effect seems to be unspecific, showing a complex dose-dependent behavioral profile. Thus, antiaggresive actions observed after the administration of the lowest dose were accompanied by increases in social investigation, avoidance/flee behaviors and non-social explorations, together with a reduction of digging behavior. This pattern reflects both approach-contact behaviors and avoidance-flee behaviors. From 4 mg/kg to 12 mg/kg, the increase in social investigation previously observed disappears, and there is a slight increase in immobility, together with a different behavioral pattern that suggests anxiogenic effects of PMA, similar to those reported after the administration of MDMA. The higher doses of PMA exhibit a behavioral profile very similar to that observed in animals treated with MDMA, with the exception of the immobility produced by PMA. These findings show for the first time the non-specific antiaggressive profile of PMA in the model of aggression induced by isolation in male mice.
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Affiliation(s)
- Mercedes Martín-López
- Department of Psychobiology, Faculty of Psychology, Campus de Teatinos s/n, University of Málaga, 29071 Málaga, Spain.
| | - Ana T Muela
- Department of Psychobiology, Faculty of Psychology, Campus de Teatinos s/n, University of Málaga, 29071 Málaga, Spain
| | - María Cavas
- Department of Psychobiology, Faculty of Psychology, Campus de Teatinos s/n, University of Málaga, 29071 Málaga, Spain
| | - José Francisco Navarro
- Department of Psychobiology, Faculty of Psychology, Campus de Teatinos s/n, University of Málaga, 29071 Málaga, Spain
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Abstract
This chapter describes how new psychoactive substances (NPS) have been involved in fatal intoxications from 2010 and onwards. It summarizes the circumstances, antemortem symptoms, and adverse effects that have led to death after ingestion of one or more NPS and tabulates concentrations, and postmortem findings from these intoxications.Consumption of NPS exerts health problems and unknown risks for the users. Data on toxicity of many NPS are scarce or nonexistent and long-term toxicity and risks are still largely unknown. In addition, purity and composition of products containing NPS are often inconsistent or not known, which places users at high risk as evidenced by hospital emergency admissions and deaths.The most serious threat to drug users are the synthetic opioids that with strong central nervous depressant effects have caused numerous accidental deaths spread over the entire globe. The synthetic cannabinoids seem to be the most unpredictable with no clear toxidrome and unknown or poorly understood mechanisms of toxicity, but with adverse effects pointing toward the cardiovascular system. The toxidromes commonly encountered after ingestion of cathinones and phenethylamines are of sympathomimetic and hallucinogenic character, which includes risk of developing a serotonin syndrome, excited delirium, and life-threatening cardiovascular effects. In comparison to their conventional "parent" drug, i.e., heroin, cannabis, and amphetamine, most NPS appear to exhibit more severe adverse effects. The deaths attributed to NPS have dramatically increased in the last years. In our opinion, this is because of the shift from synthetic cannabinoids and cathinones to the even more toxic and dangerously potent fentanyl analogues.
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Sambo DO, Lin M, Owens A, Lebowitz JJ, Richardson B, Jagnarine DA, Shetty M, Rodriquez M, Alonge T, Ali M, Katz J, Yan L, Febo M, Henry LK, Bruijnzeel AW, Daws L, Khoshbouei H. The sigma-1 receptor modulates methamphetamine dysregulation of dopamine neurotransmission. Nat Commun 2017; 8:2228. [PMID: 29263318 PMCID: PMC5738444 DOI: 10.1038/s41467-017-02087-x] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 11/05/2017] [Indexed: 12/16/2022] Open
Abstract
Dopamine neurotransmission is highly dysregulated by the psychostimulant methamphetamine, a substrate for the dopamine transporter (DAT). Through interactions with DAT, methamphetamine increases extracellular dopamine levels in the brain, leading to its rewarding and addictive properties. Methamphetamine also interacts with the sigma-1 receptor (σ1R), an inter-organelle signaling modulator. Using complementary strategies, we identified a novel mechanism for σ1R regulation of dopamine neurotransmission in response to methamphetamine. We found that σ1R activation prevents methamphetamine-induced, DAT-mediated increases in firing activity of dopamine neurons. In vitro and in vivo amperometric measurements revealed that σ1R activation decreases methamphetamine-stimulated dopamine efflux without affecting basal dopamine neurotransmission. Consistent with these findings, σ1R activation decreases methamphetamine-induced locomotion, motivated behavior, and enhancement of brain reward function. Notably, we revealed that the σ1R interacts with DAT at or near the plasma membrane and decreases methamphetamine-induced Ca2+ signaling, providing potential mechanisms. Broadly, these data provide evidence for σ1R regulation of dopamine neurotransmission and support the σ1R as a putative target for the treatment of methamphetamine addiction.
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Affiliation(s)
- Danielle O Sambo
- Department of Neuroscience, University of Florida, Gainesville, FL, 32611, USA
| | - Min Lin
- Department of Neuroscience, University of Florida, Gainesville, FL, 32611, USA
| | - Anthony Owens
- Department of Cellular & Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - Joseph J Lebowitz
- Department of Neuroscience, University of Florida, Gainesville, FL, 32611, USA
| | - Ben Richardson
- Department of Neuroscience, University of Florida, Gainesville, FL, 32611, USA
| | - Darin A Jagnarine
- Department of Psychiatry, University of Florida, Gainesville, FL, 32611, USA
| | - Madhur Shetty
- Department of Biomedical Sciences, University of North Dakota, Grand Forks, ND, 58203, USA
| | - Meghan Rodriquez
- Department of Biomedical Sciences, University of North Dakota, Grand Forks, ND, 58203, USA
| | - Taiwo Alonge
- Department of Neuroscience, University of Florida, Gainesville, FL, 32611, USA
| | - Mishaal Ali
- Department of Neuroscience, University of Florida, Gainesville, FL, 32611, USA
| | - Jonathan Katz
- Psychobiology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, 21224, USA
| | - Long Yan
- Max Plank Institute for Neuroscience Jupiter, Jupiter, FL, 33458, USA
| | - Marcelo Febo
- Department of Psychiatry, University of Florida, Gainesville, FL, 32611, USA
| | - L Keith Henry
- Department of Biomedical Sciences, University of North Dakota, Grand Forks, ND, 58203, USA
| | | | - Lynette Daws
- Department of Cellular & Integrative Physiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229, USA
| | - Habibeh Khoshbouei
- Department of Neuroscience, University of Florida, Gainesville, FL, 32611, USA.
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Jensen KL, Runegaard AH, Weikop P, Gether U, Rickhag M. Assessment of Dopaminergic Homeostasis in Mice by Use of High-performance Liquid Chromatography Analysis and Synaptosomal Dopamine Uptake. J Vis Exp 2017. [PMID: 28994779 DOI: 10.3791/56093] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Dopamine (DA) is a modulatory neurotransmitter controlling motor activity, reward processes and cognitive function. Impairment of dopaminergic (DAergic) neurotransmission is strongly associated with several central nervous system-associated diseases such as Parkinson's disease, attention-deficit-hyperactivity disorder and drug addiction1,2,3,4. Delineating disease mechanisms involving DA imbalance is critically dependent on animal models to mimic aspects of the diseases, and thus protocols that assess specific parts of the DA homeostasis are important to provide novel insights and possible therapeutic targets for these diseases. Here, we present two useful experimental protocols that when combined provide a functional read-out of the DAergic system in mice. Biochemical and functional parameters on DA homeostasis are obtained through assessment of DA levels and dopamine transporter (DAT) functionality5. When investigating the DA system, the ability to reliably measure endogenous levels of DA from adult brain is essential. Therefore, we present how to perform high-performance liquid chromatography (HPLC) on brain tissue from mice to determine levels of DA. We perform the experiment on tissue from dorsal striatum (dStr) and nucleus accumbens (NAc), but the method is also suitable for other DA-innervated brain areas. DAT is essential for reuptake of DA into the presynaptic terminal, thereby controlling the temporal and spatial activity of released DA. Knowing the levels and functionality of DAT in the striatum is of major importance when assessing DA homeostasis. Here, we provide a protocol that allows to simultaneously deduce information on surface levels and function using a synaptosomal6 DA uptake assay. Current methods combined with standard immunoblotting protocols provide the researcher with relevant tools to characterize the DAergic system.
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Affiliation(s)
- Kathrine L Jensen
- Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen
| | - Annika H Runegaard
- Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen
| | - Pia Weikop
- Laboratory of Neuropsychiatry, Psychiatric Center Copenhagen and Department of Neuroscience and Pharmacology, University of Copenhagen
| | - Ulrik Gether
- Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen
| | - Mattias Rickhag
- Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen;
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Ethanol induced antidepressant-like effect in the mouse forced swimming test: modulation by serotonergic system. Psychopharmacology (Berl) 2017; 234:447-459. [PMID: 27838747 DOI: 10.1007/s00213-016-4478-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 11/01/2016] [Indexed: 01/12/2023]
Abstract
AIM The present investigation explored the modulatory role of serotonergic transmission in the acute ethanol-induced effects on immobility time in the mouse forced swim test (FST). METHODS AND RESULTS Acute i.p. administration of ethanol (20% w/v, 2 or 2.5 g/kg, i.p.) decreased the immobility time in FST of mice, indicating its antidepressant-like effect while lower doses of ethanol (1, 1.5 g/kg, i.p.) were devoid of any effect in the FST. The mice pre-treated with a sub-effective dose of 5-HT2A agonist, DOI (10 μg/mouse, i.c.v.) or 5-HT1A receptor antagonist, WAY 100635 (0.1 μg/mouse, i.c.v.) but not with the 5-HT2A/2C antagonist, ketanserin (1.5 μg/mouse, i.c.v.) exhibited a synergistic reduction in the immobility time induced by sub-effective dose of ethanol (1.5 g/kg, i.p.). On the other hand, ethanol (2.5 g/kg, i.p.) failed to decrease the immobility time in mice, pre-treated with 5-HT1A agonist, 8-OH-DPAT (0.1 μg/mouse, i.c.v.) or ketanserin (1.5 μg/mouse, i.c.v.). In addition, pre-treatment with a 5-HT neuronal synthesis inhibitor, p-CPA (300 mg/kg, i.p. × 3 days) attenuated the anti-immobility effect ethanol (2.5 g/kg, i.p.) in mouse FST. CONCLUSIONS Thus, the results of the present study points towards the essentiality of the central 5-HT transmission at the synapse for the ethanol-induced antidepressant-like effect in the FST wherein the regulatory role of the 5-HT1A receptor or contributory role of the 5-HT2A/2C receptor-mediated mechanism is proposed in the anti-immobility effect of acute ethanol in mouse FST.
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Tyrkkö E, Andersson M, Kronstrand R. The Toxicology of New Psychoactive Substances: Synthetic Cathinones and Phenylethylamines. Ther Drug Monit 2016; 38:190-216. [PMID: 26587869 DOI: 10.1097/ftd.0000000000000263] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND New psychoactive substances (NPSs) are substitutes for classical drugs of abuse and there are now compounds available from all groups of classical drugs of abuse. During 2014, the number of synthetic cathinones increased dramatically and, together with phenylethylamines, they dominate the NPS markets in the European Union. In total, 31 cathinones and 9 phenylethylamines were encountered in 2014. The aim of this article was to summarize the existing knowledge about the basic pharmacology, metabolism, and human toxicology of relevant synthetic cathinones and phenylethylamines. Compared with existing reviews, we have also compiled the existing case reports from both fatal and nonfatal intoxications. METHODS We performed a comprehensive literature search using bibliographic databases PubMed and Web of Science, complemented with Google Scholar. The focus of the literature search was on original articles, case reports, and previously published review articles published in 2014 or earlier. RESULTS The rapid increase of NPSs is a growing concern and sets new challenges not only for societies in drug prevention and legislation but also in clinical and forensic toxicology. In vivo and in vitro studies have demonstrated that the pharmacodynamic profile of cathinones is similar to that of other psychomotor stimulants. Metabolism studies show that cathinones and phenylethylamines are extensively metabolized; however, the parent compound is usually detectable in human urine. In vitro studies have shown that many cathinones and phenylethylamines are metabolized by CYP2D6 enzymes. This indicates that these drugs may have many possible drug-drug interactions and that genetic polymorphism may influence their toxicity. However, the clinical and toxicological relevance of CYP2D6 in adverse effects of cathinones and phenylethylamines is questionable, because these compounds are metabolized by other enzymes as well. The toxidromes commonly encountered after ingestion of cathinones and phenylethylamines are mainly of sympathomimetic and hallucinogenic character with a risk of excited delirium and life-threatening cardiovascular effects. CONCLUSIONS The acute and chronic toxicity of many NPSs is unknown or very sparsely investigated. There is a need for evidence-based-treatment recommendations for acute intoxications and a demand for new strategies to analyze these compounds in clinical and forensic cases.
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Affiliation(s)
- Elli Tyrkkö
- Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, Linköping, Sweden
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Hai A, Cai LX, Lee T, Lelyveld VS, Jasanoff A. Molecular fMRI of Serotonin Transport. Neuron 2016; 92:754-765. [PMID: 27773583 DOI: 10.1016/j.neuron.2016.09.048] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 06/29/2016] [Accepted: 09/20/2016] [Indexed: 01/03/2023]
Abstract
Reuptake of neurotransmitters from the brain interstitium shapes chemical signaling processes and is disrupted in several pathologies. Serotonin reuptake in particular is important for mood regulation and is inhibited by first-line drugs for treatment of depression. Here we introduce a molecular-level fMRI technique for micron-scale mapping of serotonin transport in live animals. Intracranial injection of an MRI-detectable serotonin sensor complexed with serotonin, together with serial imaging and compartmental analysis, permits neurotransmitter transport to be quantified as serotonin dissociates from the probe. Application of this strategy to much of the striatum and surrounding areas reveals widespread nonsaturating serotonin removal with maximal rates in the lateral septum. The serotonin reuptake inhibitor fluoxetine selectively suppresses serotonin removal in septal subregions, whereas both fluoxetine and a dopamine transporter blocker depress reuptake in striatum. These results highlight promiscuous pharmacological influences on the serotonergic system and demonstrate the utility of molecular fMRI for characterization of neurochemical dynamics.
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Affiliation(s)
- Aviad Hai
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Lili X Cai
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Taekwan Lee
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Victor S Lelyveld
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
| | - Alan Jasanoff
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Department of Brain & Cognitive Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Department of Nuclear Science & Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
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12
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Gołembiowska K, Jurczak A, Kamińska K, Noworyta-Sokołowska K, Górska A. Effect of Some Psychoactive Drugs Used as 'Legal Highs' on Brain Neurotransmitters. Neurotox Res 2016; 29:394-407. [PMID: 26501352 PMCID: PMC4786600 DOI: 10.1007/s12640-015-9569-1] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 09/28/2015] [Accepted: 10/13/2015] [Indexed: 11/29/2022]
Abstract
New psychoactive "designer drugs" are synthetic compounds developed to provide similar effects to illicit drugs of abuse, but not subjected to legal control. The rapidly changing legal status of novel psychoactive drugs triggers the development of new compounds, analogs of well-known amphetamine or mescaline. New designer drugs used as substitutes in ecstasy pills are the least investigated and can cause life-threatening effects on users. The aim of our research was to examine the effects of acute administration of 4-methoxyamphetamine (PMA, 5 and 10 mg/kg), 4-methoxy-N-methylamphetamine (PMMA, 5 and 10 mg/kg), and mephedrone (MEPH, 5, 10 and 20 mg/kg) on extracellular and tissue level of dopamine (DA), 5-hydroxytryptamine (5-HT) and their metabolites in rat brain, by microdialysis method in freely moving animals and HPLC. Similarly to 3,4-methylenedioxymethamphetamine (MDMA, 5 and 10 mg/kg) PMA, PMMA and MEPH enhanced the release of DA and 5-HT in rat striatum, nucleus accumbens, and frontal cortex. DA tissue content was increased by MEPH and PMMA in striatum, by MEPH, PMA, and PMMA in nucleus accumbens, and by PMA in frontal cortex. Instead, cortical DA level was decreased by MEPH and PMMA. MEPH did not influence 5-HT tissue level in striatum and nucleus accumbens, but decreased its level in frontal cortex. PMMA increased 5-HT content in striatum, while PMA enhanced it in nucleus accumbens and frontal cortex. Observed changes in brain monoamines and their metabolites by new psychoactive drugs suggest that these drugs may be capable of development of dependence. Further experiments are needed to fully investigate the neurotoxic and abuse potential of those drugs.
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Affiliation(s)
- Krystyna Gołembiowska
- Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna, 31-343, Kraków, Poland.
| | - Alexandra Jurczak
- Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna, 31-343, Kraków, Poland
| | - Katarzyna Kamińska
- Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna, 31-343, Kraków, Poland
| | - Karolina Noworyta-Sokołowska
- Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna, 31-343, Kraków, Poland
| | - Anna Górska
- Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, 12 Smętna, 31-343, Kraków, Poland
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13
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Simmler LD, Rickli A, Hoener MC, Liechti ME. Monoamine transporter and receptor interaction profiles of a new series of designer cathinones. Neuropharmacology 2013; 79:152-60. [PMID: 24275046 DOI: 10.1016/j.neuropharm.2013.11.008] [Citation(s) in RCA: 157] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 11/11/2013] [Accepted: 11/13/2013] [Indexed: 01/28/2023]
Abstract
Psychoactive β-keto amphetamines (cathinones) are sold as "bath salts" or "legal highs" and recreationally abused. We characterized the pharmacology of a new series of cathinones, including methedrone, 4-methylethcathinone (4-MEC), 3-fluoromethcathinone (3-FMC), pentylone, ethcathinone, buphedrone, pentedrone, and N,N-dimethylcathinone. We investigated norepinephrine (NE), dopamine (DA), and serotonin (5-HT) uptake inhibition using human embryonic kidney 293 (HEK 293) cells that express the respective human monoamine transporter, the drug-induced efflux of NE, DA, and 5-HT from monoamine-preloaded cells, and binding affinity to monoamine transporters and receptors. All of the cathinones were potent NE uptake inhibitors but differed in their DA vs. 5-HT transporter inhibition profiles and monoamine release effects. Methedrone was a more potent 5-HT than DA transporter inhibitor and released NE and 5-HT similar to para-methoxymethamphetamine (PMMA), para-methoxyamphetamine (PMA), 4-methylthioamphetamine (4-MTA), and 3,4-methylenedioxymethamphetamine (MDMA). 4-MEC and pentylone equipotently inhibited all of the monoamine transporters and released 5-HT. Ethcathinone and 3-FMC inhibited NE and DA uptake and released NE, and 3-FMC also released DA similar to N-ethylamphetamine and methamphetamine. Pentedrone and N,N-dimethylcathinone were non-releasing NE and DA uptake inhibitors as previously shown for pyrovalerone cathinones. Buphedrone preferentially inhibited NE and DA uptake and also released NE. None of the cathinones bound to rodent trace amine-associated receptor 1, in contrast to the non-β-keto-amphetamines. None of the cathinones exhibited relevant binding to other monoamine receptors. In summary, we found considerable differences in the monoamine transporter interaction profiles among different cathinones and compared with related amphetamines.
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Affiliation(s)
- L D Simmler
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, University Hospital Basel and University of Basel, Hebelstrasse 2, Basel CH-4031, Switzerland
| | - A Rickli
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, University Hospital Basel and University of Basel, Hebelstrasse 2, Basel CH-4031, Switzerland
| | - M C Hoener
- Neuroscience Research, Pharmaceuticals Division, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - M E Liechti
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, University Hospital Basel and University of Basel, Hebelstrasse 2, Basel CH-4031, Switzerland.
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14
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Rickhag M, Owens WA, Winkler MT, Strandfelt KN, Rathje M, Sørensen G, Andresen B, Madsen KL, Jørgensen TN, Wörtwein G, Woldbye DPD, Sitte H, Daws LC, Gether U. Membrane-permeable C-terminal dopamine transporter peptides attenuate amphetamine-evoked dopamine release. J Biol Chem 2013; 288:27534-27544. [PMID: 23884410 DOI: 10.1074/jbc.m112.441295] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The dopamine transporter (DAT) is responsible for sequestration of extracellular dopamine (DA). The psychostimulant amphetamine (AMPH) is a DAT substrate, which is actively transported into the nerve terminal, eliciting vesicular depletion and reversal of DA transport via DAT. Here, we investigate the role of the DAT C terminus in AMPH-evoked DA efflux using cell-permeant dominant-negative peptides. A peptide, which corresponded to the last 24 C-terminal residues of DAT (TAT-C24 DAT) and thereby contained the Ca(2+)-calmodulin-dependent protein kinase IIα (CaMKIIα) binding domain and the PSD-95/Discs-large/ZO-1 (PDZ)-binding sequence of DAT, was made membrane-permeable by fusing it to the cell membrane transduction domain of the HIV-1 Tat protein (TAT-C24WT). The ability of TAT-C24WT but not a scrambled peptide (TAT-C24Scr) to block the CaMKIIα-DAT interaction was supported by co-immunoprecipitation experiments in heterologous cells. In heterologous cells, we also found that TAT-C24WT, but not TAT-C24Scr, decreased AMPH-evoked 1-methyl-4-phenylpyridinium efflux. Moreover, chronoamperometric recordings in striatum revealed diminished AMPH-evoked DA efflux in mice preinjected with TAT-C24WT. Both in heterologous cells and in striatum, the peptide did not further inhibit efflux upon KN-93-mediated inhibition of CaMKIIα activity, consistent with a dominant-negative action preventing binding of CaMKIIα to the DAT C terminus. This was further supported by the ability of a peptide with perturbed PDZ-binding sequence, but preserved CaMKIIα binding (TAT-C24AAA), to diminish AMPH-evoked DA efflux in vivo to the same extent as TAT-C24WT. Finally, AMPH-induced locomotor hyperactivity was attenuated following systemic administration of TAT-C24WT but not TAT-C24Scr. Summarized, our findings substantiate that DAT C-terminal protein-protein interactions are critical for AMPH-evoked DA efflux and suggest that it may be possible to target protein-protein interactions to modulate transporter function and interfere with psychostimulant effects.
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Affiliation(s)
- Mattias Rickhag
- Molecular Neuropharmacology Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - William A Owens
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
| | - Marie-Therese Winkler
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University Vienna, A-1090 Vienna, Austria
| | - Kristine Nørgaard Strandfelt
- Molecular Neuropharmacology Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Mette Rathje
- Molecular Neuropharmacology Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Gunnar Sørensen
- Molecular Neuropharmacology Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark; Laboratory of Neuropsychiatry, Faculty of Health and Medical Sciences, Department of Neuroscience and Pharmacology, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Bjørn Andresen
- Molecular Neuropharmacology Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Kenneth L Madsen
- Molecular Neuropharmacology Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Trine Nygaard Jørgensen
- Molecular Neuropharmacology Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Gitta Wörtwein
- Laboratory of Neuropsychiatry, Faculty of Health and Medical Sciences, Department of Neuroscience and Pharmacology, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - David P D Woldbye
- Laboratory of Neuropsychiatry, Faculty of Health and Medical Sciences, Department of Neuroscience and Pharmacology, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Harald Sitte
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University Vienna, A-1090 Vienna, Austria
| | - Lynette C Daws
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
| | - Ulrik Gether
- Molecular Neuropharmacology Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark.
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15
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Garcia-Olivares J, Torres-Salazar D, Owens WA, Baust T, Siderovski DP, Amara SG, Zhu J, Daws LC, Torres GE. Inhibition of dopamine transporter activity by G protein βγ subunits. PLoS One 2013; 8:e59788. [PMID: 23555781 PMCID: PMC3608556 DOI: 10.1371/journal.pone.0059788] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 02/18/2013] [Indexed: 12/15/2022] Open
Abstract
Uptake through the Dopamine Transporter (DAT) is the primary mechanism of terminating dopamine signaling within the brain, thus playing an essential role in neuronal homeostasis. Deregulation of DAT function has been linked to several neurological and psychiatric disorders including ADHD, schizophrenia, Parkinson’s disease, and drug addiction. Over the last 15 years, several studies have revealed a plethora of mechanisms influencing the activity and cellular distribution of DAT; suggesting that fine-tuning of dopamine homeostasis occurs via an elaborate interplay of multiple pathways. Here, we show for the first time that the βγ subunits of G proteins regulate DAT activity. In heterologous cells and brain tissue, a physical association between Gβγ subunits and DAT was demonstrated by co-immunoprecipitation. Furthermore, in vitro pull-down assays using purified proteins established that this association occurs via a direct interaction between the intracellular carboxy-terminus of DAT and Gβγ. Functional assays performed in the presence of the non-hydrolyzable GTP analog GTP-γ-S, Gβγ subunit overexpression, or the Gβγ activator mSIRK all resulted in rapid inhibition of DAT activity in heterologous systems. Gβγ activation by mSIRK also inhibited dopamine uptake in brain synaptosomes and dopamine clearance from mouse striatum as measured by high-speed chronoamperometry in vivo. Gβγ subunits are intracellular signaling molecules that regulate a multitude of physiological processes through interactions with enzymes and ion channels. Our findings add neurotransmitter transporters to the growing list of molecules regulated by G-proteins and suggest a novel role for Gβγ signaling in the control of dopamine homeostasis.
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Affiliation(s)
- Jennie Garcia-Olivares
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Delany Torres-Salazar
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - William A. Owens
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Tracy Baust
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - David P. Siderovski
- Department of Pharmacology and UNC Neuroscience Center, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Susan G. Amara
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Jun Zhu
- Department of Pharmaceutical and Biomedical Sciences, South Carolina College of Pharmacy, University of South Carolina, Columbia, South Carolina, United States of America
| | - Lynette C. Daws
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States of America
| | - Gonzalo E. Torres
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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16
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Linking the pharmacological content of ecstasy tablets to the subjective experiences of drug users. Psychopharmacology (Berl) 2012; 220:751-62. [PMID: 21993879 DOI: 10.1007/s00213-011-2529-4] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 09/26/2011] [Indexed: 12/18/2022]
Abstract
RATIONALE Most studies on the subjective effects of ecstasy are based on the assumption that the substance that was taken is 3,4-methylenedioxymethamphetamine (MDMA). However, many tablets sold as ecstasy contain other substances and MDMA in varying doses. So far, few attempts have been made to take this into account while assessing subjective effects. OBJECTIVES This study aims to link the pharmacological content of tablets sold as ecstasy to the subjective experiences reported by ecstasy users. METHODS Self-reported effects on ecstasy tablets were available from 5,786 drug users who handed in their tablets for chemical analysis at the Drug Information and Monitoring System (DIMS) in the Netherlands. Logistic regression was employed to link the pharmacological content of ecstasy tablets to the self-reported subjective effects and compare effects with MDMA to other substances present. RESULTS MDMA showed a strong association with desirable subjective effects, unparalleled by any other psychoactive substance. However, the association of MDMA was dose-dependent, with higher doses (>120 mg/tablet) likely to evoke more adverse effects. The novel psychostimulants mephedrone and p-fluoroamphetamine were considered relatively desirable, whereas meta-chlorophenylpiperazine (mCPP) and p-methoxymethamphetamine (PMMA) were strongly associated with adverse subjective effects. Also, 3,4-methylene-dioxyamphetamine (MDA) and benzylpiperazine (BZP) were not appreciated as replacement for MDMA. CONCLUSION Linking the pharmacological content of ecstasy sold on the street to subjective experiences contributes to a better understanding of the wide range of subjective effects ascribed to ecstasy and provides a strong rationale for the prolonged endurance of MDMA as the key ingredient of the ecstasy market.
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Owens WA, Williams JM, Saunders C, Avison MJ, Galli A, Daws LC. Rescue of dopamine transporter function in hypoinsulinemic rats by a D2 receptor-ERK-dependent mechanism. J Neurosci 2012; 32:2637-47. [PMID: 22357848 PMCID: PMC3310897 DOI: 10.1523/jneurosci.3759-11.2012] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 01/04/2012] [Accepted: 01/04/2012] [Indexed: 01/16/2023] Open
Abstract
The dopamine (DA) transporter (DAT) is a major target for abused drugs and a key regulator of extracellular DA. A rapidly growing literature implicates insulin as an important regulator of DAT function. We showed previously that amphetamine (AMPH)-evoked DA release is markedly impaired in rats depleted of insulin with the diabetogenic agent streptozotocin (STZ). Similarly, functional magnetic resonance imaging experiments revealed that the blood oxygenation level-dependent signal following acute AMPH administration in STZ-treated rats is reduced. Here, we report that these deficits are restored by repeated, systemic administration of AMPH (1.78 mg/kg, every other day for 8 d). AMPH stimulates DA D(2) receptors indirectly by increasing extracellular DA. Supporting a role for D(2) receptors in mediating this "rescue," the effect was completely blocked by pre-treatment of STZ-treated rats with the D(2) receptor antagonist raclopride before systemic AMPH. D(2) receptors regulate DAT cell surface expression through ERK1/2 signaling. In ex vivo striatal preparations, repeated AMPH injections increased immunoreactivity of phosphorylated ERK1/2 (p-ERK1/2) in STZ-treated but not control rats. These data suggest that repeated exposure to AMPH can rescue, by activating D(2) receptors and p-ERK signaling, deficits in DAT function that result from hypoinsulinemia. Our data confirm the idea that disorders influencing insulin levels and/or signaling, such as diabetes and anorexia, can degrade DAT function and that insulin-independent pathways are present that may be exploited as potential therapeutic targets to restore normal DAT function.
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Affiliation(s)
| | - Jason M. Williams
- Departments of Molecular Physiology and Biophysics
- Center for Molecular Neuroscience, and
- Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | | | - Malcolm J. Avison
- Pharmacology, and
- Radiology and Radiological Sciences
- Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | - Aurelio Galli
- Departments of Molecular Physiology and Biophysics
- Center for Molecular Neuroscience, and
| | - Lynette C. Daws
- Departments of Physiology and
- Pharmacology, The University of Texas Health Science Center, San Antonio, Texas 78229, and
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Mohamed WM, Hamida SB, Cassel JC, de Vasconcelos AP, Jones BC. MDMA: Interactions with other psychoactive drugs. Pharmacol Biochem Behav 2011; 99:759-74. [DOI: 10.1016/j.pbb.2011.06.032] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 05/10/2011] [Accepted: 06/28/2011] [Indexed: 10/18/2022]
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19
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Larsen MB, Sonders MS, Mortensen OV, Larson GA, Zahniser NR, Amara SG. Dopamine transport by the serotonin transporter: a mechanistically distinct mode of substrate translocation. J Neurosci 2011; 31:6605-15. [PMID: 21525301 PMCID: PMC3107525 DOI: 10.1523/jneurosci.0576-11.2011] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 03/04/2011] [Accepted: 03/10/2011] [Indexed: 01/23/2023] Open
Abstract
The serotonin transporter (SERT) is the principal mechanism for terminating serotonin (5-HT) signals in the nervous system and is a site of action for a variety of psychoactive drugs including antidepressants, amphetamines, and cocaine. Here we show that human SERTs (hSERTs) and rat SERTs are capable of robust dopamine (DA) uptake through a process that differs mechanistically from 5-HT transport in several unanticipated ways. DA transport by hSERT has a higher maximum velocity than 5-HT transport, requires significantly higher Na(+) and Cl(-) concentrations to sustain transport, is inhibited noncompetitively by 5-HT, and is more sensitive to SERT inhibitors, including selective serotonin reuptake inhibitors. We use a thiol-reactive methane thiosulfonate (MTS) reagent to modify a conformationally sensitive cysteine residue to demonstrate that hSERT spends more time in an outward facing conformation when transporting DA than when transporting 5-HT. Cotransfection of an inactive or an MTS-sensitive SERT with wild-type SERT subunits reveals an absence of cooperative interactions between subunits during DA but not 5-HT transport. To establish the physiological relevance of this mechanism for DA clearance, we show using in vivo high-speed chronoamperometry that SERT has the capacity to clear extracellularly applied DA in the hippocampal CA3 region of anesthetized rats. Together, these observations suggest the possibility that SERT serves as a DA transporter in vivo and highlight the idea that there can be distinct modes of transport of alternative physiological substrates by SERT.
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Affiliation(s)
- Mads Breum Larsen
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260
| | - Mark S. Sonders
- Center for Molecular Recognition, Columbia University and New York State Psychiatric Institute, New York, New York 10032, and
| | - Ole Valente Mortensen
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260
| | - Gaynor A. Larson
- Department of Pharmacology, University of Colorado Denver, Aurora, Colorado 80045
| | - Nancy R. Zahniser
- Department of Pharmacology, University of Colorado Denver, Aurora, Colorado 80045
| | - Susan G. Amara
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15260
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Behavioral, hyperthermic and pharmacokinetic profile of para-methoxymethamphetamine (PMMA) in rats. Pharmacol Biochem Behav 2011; 98:130-9. [DOI: 10.1016/j.pbb.2010.12.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 11/14/2010] [Accepted: 12/08/2010] [Indexed: 11/21/2022]
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21
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Organic cation transporter 3: Keeping the brake on extracellular serotonin in serotonin-transporter-deficient mice. Proc Natl Acad Sci U S A 2008; 105:18976-81. [PMID: 19033200 DOI: 10.1073/pnas.0800466105] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Mood disorders cause much suffering and are the single greatest cause of lost productivity worldwide. Although multiple medications, along with behavioral therapies, have proven effective for some individuals, millions of people lack an effective therapeutic option. A common serotonin (5-HT) transporter (5-HTT/SERT, SLC6A4) polymorphism is believed to confer lower 5-HTT expression in vivo and elevates risk for multiple mood disorders including anxiety, alcoholism, and major depression. Importantly, this variant is also associated with reduced responsiveness to selective 5-HT reuptake inhibitor antidepressants. We hypothesized that a reduced antidepressant response in individuals with a constitutive reduction in 5-HTT expression could arise because of the compensatory expression of other genes that inactivate 5-HT in the brain. A functionally upregulated alternate transporter for 5-HT may prevent extracellular 5-HT from rising to levels sufficiently high enough to trigger the adaptive neurochemical events necessary for therapeutic benefit. Here we demonstrate that expression of the organic cation transporter type 3 (OCT3, SLC22A3), which also transports 5-HT, is upregulated in the brains of mice with constitutively reduced 5-HTT expression. Moreover, the OCT blocker decynium-22 diminishes 5-HT clearance and exerts antidepressant-like effects in these mice but not in WT animals. OCT3 may be an important transporter mediating serotonergic signaling when 5-HTT expression or function is compromised.
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Unfaithful neurotransmitter transporters: focus on serotonin uptake and implications for antidepressant efficacy. Pharmacol Ther 2008; 121:89-99. [PMID: 19022290 DOI: 10.1016/j.pharmthera.2008.10.004] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2008] [Accepted: 10/14/2008] [Indexed: 01/11/2023]
Abstract
Biogenic amine transporters for serotonin, norepinephrine and dopamine (SERT, NET and DAT respectively), are the key players terminating transmission of these amines in the central nervous system by their high-affinity uptake. They are also major targets for many antidepressant drugs. Interestingly however, drugs targeted to a specific transporter do not appear to be as clinically efficacious as those that block two or all three of these transporters. A growing body of literature, reviewed here, supports the idea that promiscuity among these transporters (the uptake of multiple amines in addition to their "native" transmitter) may account for improved therapeutic effects of dual and triple uptake blockers. However, even these drugs do not provide effective treatment outcomes for all individuals. An emerging literature suggests that "non-traditional" transporters such as organic cation transporters (OCT) and the plasma membrane monoamine transporter (PMAT) may contribute to the less than hoped for efficacy of currently prescribed uptake inhibitors. OCT and PMAT are capable of clearing biogenic amines from extracellular fluid and may serve to buffer the effects of frontline antidepressants, such as selective serotonin reuptake inhibitors. In addition, polymorphisms that occur in the genes encoding the transporters can lead to variation in transporter expression and function (e.g. the serotonin transporter linked polymorphic region; 5-HTTLPR) and can have profound effects on treatment outcome. This may be accounted for, in part, by compensatory adaptations in other transporters. This review synthesizes the existing literature, focusing on serotonin to illustrate and revive a model for the rationale design of improved antidepressants.
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Williams JM, Owens WA, Turner GH, Saunders C, Dipace C, Blakely RD, France CP, Gore JC, Daws LC, Avison MJ, Galli A. Hypoinsulinemia regulates amphetamine-induced reverse transport of dopamine. PLoS Biol 2007; 5:e274. [PMID: 17941718 PMCID: PMC2020502 DOI: 10.1371/journal.pbio.0050274] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Accepted: 08/17/2007] [Indexed: 11/18/2022] Open
Abstract
The behavioral effects of psychomotor stimulants such as amphetamine (AMPH) arise from their ability to elicit increases in extracellular dopamine (DA). These AMPH-induced increases are achieved by DA transporter (DAT)-mediated transmitter efflux. Recently, we have shown that AMPH self-administration is reduced in rats that have been depleted of insulin with the diabetogenic agent streptozotocin (STZ). In vitro studies suggest that hypoinsulinemia may regulate the actions of AMPH by inhibiting the insulin downstream effectors phosphotidylinositol 3-kinase (PI3K) and protein kinase B (PKB, or Akt), which we have previously shown are able to fine-tune DAT cell-surface expression. Here, we demonstrate that striatal Akt function, as well as DAT cell-surface expression, are significantly reduced by STZ. In addition, our data show that the release of DA, determined by high-speed chronoamperometry (HSCA) in the striatum, in response to AMPH, is severely impaired in these insulin-deficient rats. Importantly, selective inhibition of PI3K with LY294002 within the striatum results in a profound reduction in the subsequent potential for AMPH to evoke DA efflux. Consistent with our biochemical and in vivo electrochemical data, findings from functional magnetic resonance imaging experiments reveal that the ability of AMPH to elicit positive blood oxygen level-dependent signal changes in the striatum is significantly blunted in STZ-treated rats. Finally, local infusion of insulin into the striatum of STZ-treated animals significantly recovers the ability of AMPH to stimulate DA release as measured by high-speed chronoamperometry. The present studies establish that PI3K signaling regulates the neurochemical actions of AMPH-like psychomotor stimulants. These data suggest that insulin signaling pathways may represent a novel mechanism for regulating DA transmission, one which may be targeted for the treatment of AMPH abuse and potentially other dopaminergic disorders.
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Affiliation(s)
- Jason M Williams
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Center for Molecular Neuroscience, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - W. Anthony Owens
- Department of Physiology, The University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Gregory H Turner
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Christine Saunders
- Center for Molecular Neuroscience, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Concetta Dipace
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Center for Molecular Neuroscience, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Randy D Blakely
- Center for Molecular Neuroscience, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Charles P France
- Department of Pharmacology, The University of Texas Health Science Center, San Antonio, Texas, United States of America
- Department of Psychiatry, The University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - John C Gore
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Lynette C Daws
- Department of Physiology, The University of Texas Health Science Center, San Antonio, Texas, United States of America
- Department of Pharmacology, The University of Texas Health Science Center, San Antonio, Texas, United States of America
| | - Malcolm J Avison
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Aurelio Galli
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Center for Molecular Neuroscience, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
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24
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Norrholm SD, Horton DB, Dwoskin LP. The promiscuity of the dopamine transporter: implications for the kinetic analysis of [3H]serotonin uptake in rat hippocampal and striatal synaptosomes. Neuropharmacology 2007; 53:982-9. [PMID: 18022203 DOI: 10.1016/j.neuropharm.2007.10.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2007] [Revised: 08/23/2007] [Accepted: 10/01/2007] [Indexed: 11/29/2022]
Abstract
Evidence indicates that monoaminergic neurotransmitter transporters are promiscuous, transporting substrates other than their cognate neurotransmitters. For example, serotonin is transported by the dopamine transporter (DAT) under conditions in which serotonin transporter (SERT) activity is eliminated (e.g., pharmacological inhibition). We performed a kinetic analysis of [(3)H]serotonin uptake in rat striatal synaptosomes (expressing DAT and SERT) and hippocampal synaptosomes (expressing SERT, but not DAT). Nonspecific [(3)H]serotonin uptake was defined as the amount of uptake remaining in the presence of fluoxetine (10microM) or paroxetine (0.05microM). In hippocampal synaptosomes, K(m) and V(max) values for [(3)H]serotonin uptake did not differ whether fluoxetine or paroxetine was used to define nonspecific uptake. However, in striatal synaptosomes, both K(m) and V(max) values for [(3)H]serotonin uptake were greater when fluoxetine, rather than paroxetine, was used to define nonspecific uptake. These data suggest that, at the concentrations employed, fluoxetine inhibits serotonin uptake at both DAT and SERT, whereas paroxetine only inhibits serotonin uptake at SERT. Thus, when DAT is inhibited by GBR 12909, kinetic parameters for serotonin uptake via SERT in striatum are not different from those obtained in hippocampus. These findings have important implications regarding the analysis of monoaminergic reuptake in brain regions exhibiting heterogeneous transporter expression.
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Affiliation(s)
- Seth D Norrholm
- College of Pharmacy, Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY 40536-0082, USA.
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25
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Stanley N, Salem A, Irvine RJ. The effects of co-administration of 3,4-methylenedioxymethamphetamine (“ecstasy”) or para-methoxyamphetamine and moclobemide at elevated ambient temperatures on striatal 5-HT, body temperature and behavior in rats. Neuroscience 2007; 146:321-9. [PMID: 17306465 DOI: 10.1016/j.neuroscience.2007.01.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Revised: 12/18/2006] [Accepted: 01/11/2007] [Indexed: 11/24/2022]
Abstract
We have recently demonstrated that co-administration of 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") with the reversible monoamine oxidase type A (MAO-A) inhibitor moclobemide at an ambient temperature of 22 degrees C significantly increases striatal 5-HT outflow and 5-HT-mediated behaviors. In the present study, using microdialysis, we examined the effects of co-administration of MDMA or para-methoxyamphetamine (PMA) with moclobemide on striatal 5-HT outflow at the elevated ambient temperatures of 30 degrees C. Samples were collected every 30 min for 4 h and analyzed by high-performance liquid chromatography assay with electrochemical detection (HPLC-ED). 5-HT-mediated effects on body temperature and behavior were also recorded. Rats were treated with either saline or 20 mg/kg (i.p.) moclobemide, followed by 10 mg/kg (i.p.) MDMA, 10 mg/kg (i.p.) PMA or saline 60 min later. Both MDMA and PMA produced significant increases in 5-HT outflow (370% peak and 309% peak, respectively, P<0.05). MDMA and PMA significantly increased body temperature (+2.0 degrees C and +2.1 degrees C, respectively, P<0.01) and drug-related behaviors (P<0.05). When MDMA or PMA was co-administered with moclobemide, additional significant increases were seen in 5-HT outflow (850% peak, P<0.01 and 1450% peak, P<0.001, respectively) and only MDMA showed additional significant increase in body temperature (+5.0 degrees C, P<0.001). No additional increases were seen in behavioral activity. When moclobemide was co-administered with MDMA, sustained increases in body temperature were recorded that were significantly higher than with MDMA alone and such increases were not observed in our previous study at normal room temperature. Our results suggest greater risk of MDMA-induced adverse effects on body temperature regulation, compared with PMA, when used in combination with moclobemide at elevated ambient temperatures.
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Affiliation(s)
- N Stanley
- Discipline of Pharmacology, School of Medical Sciences, Medical School North, University of Adelaide, Adelaide, South Australia 5005, Australia
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26
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Price DA, Owens WA, Gould GG, Frazer A, Roberts JL, Daws LC, Giuffrida A. CB1-independent inhibition of dopamine transporter activity by cannabinoids in mouse dorsal striatum. J Neurochem 2007; 101:389-96. [PMID: 17250681 DOI: 10.1111/j.1471-4159.2006.04383.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Cannabinoid drugs are known to affect dopaminergic neurotransmission in the basal ganglia circuitry. In this study, we used in vitro and in vivo techniques to investigate whether cannabinoid agonists and antagonist could affect dopaminergic transmission in the striatum by acting at the dopamine transporter. Incubation of striatal synaptosomes with the cannabinoid agonists WIN55,212-2 or methanandamide decreased dopamine uptake (IC(50) = 2.0 micromol/L and 3.1 micromol/L, respectively). A similar inhibitory effect was observed after application of the inactive WIN55,212-2 isomer, S(-)WIN55,212-3. The CB(1) antagonist AM251 did not reverse WIN55,212-2 effect but rather mimicked it. WIN55,212-2 and AM251 partially displaced the binding of the cocaine analog [(3)H]WIN35,428, thus acting as dopamine transporter pseudo-substrates in the high micromolar range. High-speed chronoamperometry measurements showed that WIN55,212-2 (4 mg/kg, i.p.) caused significant release of endogenous dopamine via activation of CB(1) receptors, followed by a reduction of dopamine clearance. This reduction was CB(1)-independent, as it was mimicked by S(-)WIN55,212-3. Administration of AM251 (1 and 4 mg/kg, i.p.) increased the signal amplitude and reduced the clearance of dopamine pressure ejected into the striatum. These results indicate that both cannabinoid agonists and antagonists inhibit dopamine transporter activity via molecular targets other than CB(1) receptors.
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Affiliation(s)
- David A Price
- Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229-3900, USA
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27
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Callaghan PD, Owens WA, Javors MA, Sanchez TA, Jones DJ, Irvine RJ, Daws LC. In vivo analysis of serotonin clearance in rat hippocampus reveals that repeated administration of p-methoxyamphetamine (PMA), but not 3,4-methylenedioxymethamphetamine (MDMA), leads to long-lasting deficits in serotonin transporter function. J Neurochem 2006; 100:617-27. [PMID: 17181558 DOI: 10.1111/j.1471-4159.2006.04247.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
p-Methoxyamphetamine (PMA) has been implicated in fatalities as a result of 'ecstasy' (MDMA) overdose worldwide. Like MDMA, acute effects are associated with marked changes in serotonergic neurotransmission, but the long-term effects of PMA are poorly understood. The aim of this study was to determine the effect of repeated PMA administration on in vitro measures of neurodegeneration: serotonin (5-HT) uptake, 5-HT transporter (SERT) density and 5-HT content in the hippocampus, and compare with effects on in vivo 5-HT clearance. Male rats received PMA, MDMA (4 or 15 mg/kg s.c., twice daily) or vehicle for 4 days and 2 weeks later indices of SERT function were measured. [(3)H]5-HT uptake into synaptosomes and [(3)H]cyanoimipramine binding to the SERT were significantly reduced by both PMA and MDMA treatments. 5-HT content was reduced in MDMA-, but not PMA-treatment. In contrast, clearance of locally applied 5-HT measured in vivo by chronoamperometry was only reduced in rats treated with 15 mg/kg PMA. The finding that 5-HT clearance in vivo was unaltered by MDMA treatment suggests that in vitro measures of 5-HT axonal degeneration do not necessarily predict potential compensatory mechanisms that maintain SERT function under basal conditions.
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Affiliation(s)
- Paul D Callaghan
- Department of Physiology, The University of Texas Health Science Center at San Antonio, TX 78229-3900, USA
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28
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Fog JU, Khoshbouei H, Holy M, Owens WA, Vaegter CB, Sen N, Nikandrova Y, Bowton E, McMahon DG, Colbran RJ, Daws LC, Sitte HH, Javitch JA, Galli A, Gether U. Calmodulin kinase II interacts with the dopamine transporter C terminus to regulate amphetamine-induced reverse transport. Neuron 2006; 51:417-29. [PMID: 16908408 DOI: 10.1016/j.neuron.2006.06.028] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Revised: 05/24/2006] [Accepted: 06/27/2006] [Indexed: 11/22/2022]
Abstract
Efflux of dopamine through the dopamine transporter (DAT) is critical for the psychostimulatory properties of amphetamines, but the underlying mechanism is unclear. Here we show that Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) plays a key role in this efflux. CaMKIIalpha bound to the distal C terminus of DAT and colocalized with DAT in dopaminergic neurons. CaMKIIalpha stimulated dopamine efflux via DAT in response to amphetamine in heterologous cells and in dopaminergic neurons. CaMKIIalpha phosphorylated serines in the distal N terminus of DAT in vitro, and mutation of these serines eliminated the stimulatory effects of CaMKIIalpha. A mutation of the DAT C terminus impairing CaMKIIalpha binding also impaired amphetamine-induced dopamine efflux. An in vivo role for CaMKII was supported by chronoamperometry measurements showing reduced amphetamine-induced dopamine efflux in response to the CaMKII inhibitor KN93. Our data suggest that CaMKIIalpha binding to the DAT C terminus facilitates phosphorylation of the DAT N terminus and mediates amphetamine-induced dopamine efflux.
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Affiliation(s)
- Jacob U Fog
- Molecular Neuropharmacology Group and Center for Pharmacogenomics, Department of Pharmacology, The Panum Institute, University of Copenhagen, DK-2200 Copenhagen, Denmark
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29
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Callaghan PD, Farrand K, Salem A, Hughes P, Daws LC, Irvine RJ. Repeated administration of the substituted amphetamine p-methoxyamphetamine produces reductions in cortical 5-HT transporter binding but not 5-HT content, unlike 3,4-methylenedioxyamethamphetamine. Eur J Pharmacol 2006; 546:74-81. [PMID: 16925993 DOI: 10.1016/j.ejphar.2006.07.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2006] [Revised: 07/13/2006] [Accepted: 07/17/2006] [Indexed: 01/18/2023]
Abstract
Worldwide growth in p-methoxyamphetamine (PMA) usage amongst 'ecstasy' users indicates a proportionally greater incidence of acute toxicity compared to 3,4-methylenedioxymethamphetamine (MDMA). While longer-term use of MDMA appears to produce degeneration of 5-hydroxytryptamine (5-HT, serotonin) neurons, PMA effects are poorly understood. The aim of this study was to determine the effect of repeated PMA administration on two indices of 5-HT axonal degeneration, cortical brain 5-HT transporter (SERT) density and 5-HT/5-hydroxyindolacetic acid (5-HIAA) content. Treatment of male rats once daily for 4 days (10 or 20 mg/kg) with PMA or MDMA resulted in significant reductions (20 mg/kg: 53% and 23% of vehicle treatment respectively) in [(3)H]-paroxetine binding (SERT density) one week after final drug administration. When rats were housed at a higher ambient temperature (28 degrees C vs. 22 degrees C) for 6 h after dosing, no additive effect was seen for either drug. A more intensive dosing regimen (10 or 20 mg/kg twice daily for 4 days) was used to examine PMA/MDMA effects on cortical 5-HT content. Two weeks after MDMA treatment, significant reductions in cortical 5-HT content (20 mg/kg: 39% of vehicle treatment) were seen. However, PMA did not alter cortical 5-HT content, yet reduced cortical 5-HIAA content (20 mg/kg: 72% of vehicle treatment). These data suggest PMA has severe long-term implications clinically for alteration of 5-HT neurotransmission that may differ from MDMA, but may not necessarily be interpreted as a degeneration of 5-HT fibres.
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Affiliation(s)
- Paul D Callaghan
- Discipline of Pharmacology, School of Medical Sciences, Medical School North, The University of Adelaide, Adelaide, South Australia, 5005, Australia
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30
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Daws LC, Montañez S, Munn JL, Owens WA, Baganz NL, Boyce-Rustay JM, Millstein RA, Wiedholz LM, Murphy DL, Holmes A. Ethanol inhibits clearance of brain serotonin by a serotonin transporter-independent mechanism. J Neurosci 2006; 26:6431-8. [PMID: 16775130 PMCID: PMC6674049 DOI: 10.1523/jneurosci.4050-05.2006] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Brain serotonin (5-HT) modulates the neural and behavioral effects of ethanol in a manner that remains poorly understood. Here we show that treatment with physiologically relevant (i.e., moderately intoxicating) doses of ethanol inhibits clearance of 5-HT from extracellular fluid in the mouse hippocampus. This finding demonstrates, in vivo, a key molecular mechanism by which ethanol modulates serotonergic neurotransmission. The 5-HT transporter (5-HTT) is the principle means of 5-HT reuptake in the brain and an obvious candidate mechanism for the effect of ethanol to inhibit 5-HT clearance. However, our second major finding was that genetic inactivation of the 5-HTT in a knock-out mouse not only failed to prevent ethanol-induced inhibition of 5-HT clearance, but actually potentiated this effect. Ethanol-induced inhibition of 5-HT clearance was also potentiated in nonmutant mice by cotreatment with a 5-HTT antagonist. Providing a link with potential behavioral manifestations of this neural phenotype, 5-HTT knock-out mice also exhibited exaggerated sensitivity to behavioral intoxication, as assayed by the sedative/hypnotic effects of ethanol. This clearly demonstrates that the 5-HTT is not necessary for the neural and behavioral effects of ethanol observed herein and that genetic or pharmacological inactivation of the 5-HTT unmasks involvement of other principle mechanisms. These data are intriguing given growing evidence implicating the 5-HTT in the pathophysiology and treatment of alcoholism and neuropsychiatric conditions frequently comorbid with alcoholism, such as depression. The present findings provide new insights into the actions of ethanol on brain function and behavior.
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Affiliation(s)
- Lynette C Daws
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229-3900, USA.
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