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Hota SK, Singh G, Murarka S. Direct C-H alkylation of 3,4-dihydroquinoxaline-2-ones with N-(acyloxy)phthalimides via radical-radical cross coupling. Chem Commun (Camb) 2024; 60:6268-6271. [PMID: 38808396 DOI: 10.1039/d4cc01837k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
We present an organophotoredox-catalyzed direct Csp3-H alkylation of 3,4-dihydroquinoxalin-2-ones employing N-(acyloxy)pthalimides to provide corresponding products in good yields. A broad spectrum of NHPI esters (1°, 2°, 3°, and sterically encumbered) participates in the photoinduced alkylation of a variety of 3,4-dihydroquinoxalin-2-ones. In general, mild conditions, broad scope with good functional group tolerance, and scalability are the salient features of this direct alkylation process.
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Affiliation(s)
- Sudhir Kumar Hota
- Department of Chemistry, Indian Institute of Technology Jodhpur, Karwar-342037, Rajasthan, India.
| | - Gulshan Singh
- Department of Chemistry, Indian Institute of Technology Jodhpur, Karwar-342037, Rajasthan, India.
| | - Sandip Murarka
- Department of Chemistry, Indian Institute of Technology Jodhpur, Karwar-342037, Rajasthan, India.
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2
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Yates JR. Quantifying conditioned place preference: a review of current analyses and a proposal for a novel approach. Front Behav Neurosci 2023; 17:1256764. [PMID: 37693282 PMCID: PMC10484009 DOI: 10.3389/fnbeh.2023.1256764] [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: 07/11/2023] [Accepted: 08/02/2023] [Indexed: 09/12/2023] Open
Abstract
Conditioned place preference (CPP) is used to measure the conditioned rewarding effects of a stimulus, including food, drugs, and social interaction. Because various analytic approaches can be used to quantify CPP, this can make direct comparisons across studies difficult. Common methods for analyzing CPP involve comparing the time spent in the CS+ compartment (e.g., compartment paired with drug) at posttest to the time spent in the CS+ compartment at pretest or to the CS- compartment (e.g., compartment paired with saline) at posttest. Researchers can analyze the time spent in the compartment(s), or they can calculate a difference score [(CS+post - CS+pre) or (CS+post - CS-post)] or a preference ratio (e.g., CS+post/(CS+post + CS-post)). While each analysis yields results that are, overall, highly correlated, there are situations in which different analyses can lead to discrepant interpretations. The current paper discusses some of the limitations associated with current analytic approaches and proposes a novel method for quantifying CPP, the adjusted CPP score, which can help resolve the limitations associated with current approaches. The adjusted CPP score is applied to both hypothetical and previously published data. Another major topic covered in this paper is methodologies for determining if individual subjects have met criteria for CPP. The paper concludes by highlighting ways in which researchers can increase transparency and replicability in CPP studies.
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Affiliation(s)
- Justin R. Yates
- Department of Psychological Science, Northern Kentucky University, Highland Heights, KY, United States
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3
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Chellian R, Behnood-Rod A, Wilson R, Lin K, King GWY, Bruijnzeel AW. Dopamine D1-like receptor activation decreases nicotine intake in rats with short or long access to nicotine. Addict Biol 2023; 28:e13312. [PMID: 37500487 PMCID: PMC10403282 DOI: 10.1111/adb.13312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 03/14/2023] [Accepted: 06/16/2023] [Indexed: 07/29/2023]
Abstract
The use of nicotine and tobacco products is highly addictive. The dopaminergic system plays a key role in the initiation and maintenance of nicotine intake. Dopamine D1-like receptor blockade diminishes nicotine intake in rats with daily short (1 h) access to nicotine, but little is known about the effects of dopamine receptor antagonists or agonists on nicotine intake in rats with intermittent long (23 h) access. Because of the extended access conditions and high nicotine intake, the intermittent long access procedure might model smoking and vaping better than short access models. We investigated the effects of the dopamine D1-like receptor antagonist SCH 23390 and the D1-like receptor agonist A77636 on nicotine intake in male rats with intermittent short or long access to nicotine. The rats self-administered nicotine for 5 days (1 h/day) and were then given 15 intermittent short (1 h/day) or long (23 h/day) access sessions (3 sessions/week, 0.06 mg/kg/inf). The D1-like receptor antagonist SCH 23390 decreased nicotine intake to a similar degree in rats with short or long access to nicotine. The D1-like receptor agonist A77636 induced a greater decrease in nicotine intake in the rats with long access to nicotine than in rats with short access. Treatment with A77636 induced a prolonged decrease in nicotine intake that lasted throughout the dark and light phase in the long access rats. These findings indicate that blockade and stimulation of D1-like receptors decrease nicotine intake in an intermittent long access animal model that closely models human smoking and vaping.
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Affiliation(s)
| | - Azin Behnood-Rod
- Department of Psychiatry, University of Florida, Gainesville, Florida, USA
| | - Ryann Wilson
- Department of Psychiatry, University of Florida, Gainesville, Florida, USA
| | - Karen Lin
- Department of Psychiatry, University of Florida, Gainesville, Florida, USA
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4
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Przegaliński E, Witek K, Wydra K, Kotlińska JH, Filip M. 5-HT2C Receptor Stimulation in Obesity Treatment: Orthosteric Agonists vs. Allosteric Modulators. Nutrients 2023; 15:nu15061449. [PMID: 36986191 PMCID: PMC10058696 DOI: 10.3390/nu15061449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 03/09/2023] [Accepted: 03/12/2023] [Indexed: 03/22/2023] Open
Abstract
Obesity is a substantial health and economic issue, and serotonin (5-hydroxytryptamine, 5-HT) is an important neurotransmitter system involved in the regulation of body weight. The 5-HT2C receptors (5-HT2CRs), one of 16 of the 5-HT receptor (5-HTRs) subtypes, play a significant role in food intake and body weight control. In this review, we focused on the 5-HTR agonists, such as fenfluramines, sibutramine, and lorcaserin, which act directly or indirectly at 5-HT2CRs and have been introduced into the clinic as antiobesity medications. Due to their unwanted effects, they were withdrawn from the market. The 5-HT2CR positive allosteric modulators (PAMs) can be potentially safer active drugs than 5-HT2CR agonists. However, more in vivo validation of PAMs is required to fully determine if these drugs will be effective in obesity prevention and antiobesity pharmacology treatment. Methodology strategy: This review focuses on the role of 5-HT2CR agonism in obesity treatment, such as food intake regulation and weight gain. The literature was reviewed according to the review topic. We searched the PubMed and Scopus databases and Multidisciplinary Digital Publishing Institute open-access scientific journals using the following keyword search strategy depending on the chapter phrases: (1) “5-HT2C receptor” AND “food intake”, and (2) “5-HT2C receptor” AND “obesity” AND “respective agonists”, and (3) “5-HT2C receptor” AND “PAM”. We included preclinical studies (only present the weight loss effects) and double-blind, placebo-controlled, randomized clinical trials published since the 1975s (mostly related to antiobesity treatment), and excluded the pay-walled articles. After the search process, the authors selected, carefully screened, and reviewed appropriate papers. In total, 136 articles were included in this review.
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Affiliation(s)
- Edmund Przegaliński
- Department of Drug Addiction Pharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, Smętna Street 12, 31-343 Krakow, Poland; (K.W.); (K.W.); (M.F.)
- Correspondence:
| | - Kacper Witek
- Department of Drug Addiction Pharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, Smętna Street 12, 31-343 Krakow, Poland; (K.W.); (K.W.); (M.F.)
| | - Karolina Wydra
- Department of Drug Addiction Pharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, Smętna Street 12, 31-343 Krakow, Poland; (K.W.); (K.W.); (M.F.)
| | - Jolanta H. Kotlińska
- Department of Pharmacology and Pharmacodynamics, Medical University of Lublin, Chodźki Street 4a, 20-093 Lublin, Poland;
| | - Małgorzata Filip
- Department of Drug Addiction Pharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, Smętna Street 12, 31-343 Krakow, Poland; (K.W.); (K.W.); (M.F.)
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5
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Bombardi C, Delicata F, Tagliavia C, Grandis A, Pierucci M, Marino Gammazza A, Casarrubea M, De Deurwaerdère P, Di Giovanni G. Lateral Habenula 5-HT 2C Receptor Function Is Altered by Acute and Chronic Nicotine Exposures. Int J Mol Sci 2021; 22:ijms22094775. [PMID: 33946328 PMCID: PMC8124296 DOI: 10.3390/ijms22094775] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/25/2021] [Accepted: 04/27/2021] [Indexed: 12/11/2022] Open
Abstract
Serotonin (5-HT) is important in some nicotine actions in the CNS. Among all the 5-HT receptors (5-HTRs), the 5-HT2CR has emerged as a promising drug target for smoking cessation. The 5-HT2CRs within the lateral habenula (LHb) may be crucial for nicotine addiction. Here we showed that after acute nicotine tartrate (2 mg/kg, i.p.) exposure, the 5-HT2CR agonist Ro 60-0175 (5–640 µg/kg, i.v.) increased the electrical activity of 42% of the LHb recorded neurons in vivo in rats. Conversely, after chronic nicotine treatment (6 mg/kg/day, i.p., for 14 days), Ro 60-0175 was incapable of affecting the LHb neuronal discharge. Moreover, acute nicotine exposure increased the 5-HT2CR-immunoreactive (IR) area while decreasing the number of 5-HT2CR-IR neurons in the LHb. On the other hand, chronic nicotine increased both the 5-HT2CR-IR area and 5-HT2CR-IR LHb neurons in the LHb. Western blot analysis confirmed these findings and further revealed an increase of 5-HT2CR expression in the medial prefrontal cortex after chronic nicotine exposure not detected by the immunohistochemistry. Altogether, these data show that acute and chronic nicotine exposure differentially affect the central 5-HT2CR function mainly in the LHb and this may be relevant in nicotine addiction and its treatment.
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Affiliation(s)
- Cristiano Bombardi
- Department of Veterinary Medical Sciences, University of Bologna, Via Tolara di Sopra, 50, 40064 Ozzano dell’Emilia, Italy; (C.B.); (C.T.); (A.G.)
| | - Francis Delicata
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, MSD2080 Msida, Malta; (F.D.); (M.P.)
| | - Claudio Tagliavia
- Department of Veterinary Medical Sciences, University of Bologna, Via Tolara di Sopra, 50, 40064 Ozzano dell’Emilia, Italy; (C.B.); (C.T.); (A.G.)
| | - Annamaria Grandis
- Department of Veterinary Medical Sciences, University of Bologna, Via Tolara di Sopra, 50, 40064 Ozzano dell’Emilia, Italy; (C.B.); (C.T.); (A.G.)
| | - Massimo Pierucci
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, MSD2080 Msida, Malta; (F.D.); (M.P.)
| | - Antonella Marino Gammazza
- Section of Human Anatomy, Department of Biomedicine, Neuroscience and Advanced Diagnostics (BiND), University of Palermo, 90127 Palermo, Italy;
| | - Maurizio Casarrubea
- Laboratory of Behavioral Physiology, Human Physiology Section “Giuseppe Pagano”, Department of Biomedicine, Neuroscience and Advanced Diagnostics (BiND), University of Palermo, 90127 Palermo, Italy;
| | - Philippe De Deurwaerdère
- Unité Mixte de Recherche 5287, Centre National de la Recherche Scientifique, 146 rue Léo Saignat, B.P.281, CEDEX, F-33000 Bordeaux, France;
| | - Giuseppe Di Giovanni
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, MSD2080 Msida, Malta; (F.D.); (M.P.)
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
- Correspondence: or ; Tel.: +356-23402776
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6
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Chronic Lorcaserin Treatment Reverses the Nicotine Withdrawal-Induced Disruptions to Behavior and Maturation in Developing Neurons in the Hippocampus of Rats. Int J Mol Sci 2021; 22:ijms22020868. [PMID: 33467149 PMCID: PMC7831001 DOI: 10.3390/ijms22020868] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 01/11/2021] [Accepted: 01/12/2021] [Indexed: 11/17/2022] Open
Abstract
Preclinical data have shown that treatment with serotonin (5-HT)2C receptor agonists inhibits the behavioral effects of nicotine, including self-administration, reinstatement, and locomotor responses to nicotine. Since the data on the effects of 5-HT2C receptor agonism on nicotine withdrawal signs are limited, we aimed to investigate whether 5-HT2C receptor agonism alleviated the behavioral and neurobiochemical (hippocampal neurogenesis) consequences of nicotine withdrawal in Sprague-Dawley rats. Our data indicate that withdrawal from nicotine self-administration induced locomotor hyperactivity, lengthened immobility time (the forced swim test), induced ‘drug-seeking’ behavior and deficits in cognition-like behavior (the novel object recognition task). A two-week exposure to the 5-HT2C receptor agonist lorcaserin attenuated locomotor hyperactivity and induced recovery from depression-like behavior. Analyses of brain slices from nicotine-withdrawn animals revealed that lorcaserin treatment recovered the reduced number of doublecortin (DCX)-positive cells, but it did not affect the number of Ki-67- or 5-bromo-2’-deoxyuridine (BrdU)-positive cells or the maturation of proliferating neurons in drug-weaned rats. To summarize, we show that lorcaserin alleviated locomotor responses and depression-like state during nicotine withdrawal. We propose that the modulatory effect of lorcaserin on the ‘affective’ aspects of nicotine cessation may be linked to the positive changes caused by the compound in hippocampal neurogenesis during nicotine withdrawal.
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Kasatkina SO, Stepanova EE, Dmitriev MV, Mokrushin IG, Maslivets AN. Synthesis of pyrimido[1,6- a]quinoxalines via intermolecular trapping of thermally generated acyl(quinoxalin-2-yl)ketenes by Schiff bases. Beilstein J Org Chem 2018; 14:1734-1742. [PMID: 30112078 PMCID: PMC6071730 DOI: 10.3762/bjoc.14.147] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 06/26/2018] [Indexed: 12/31/2022] Open
Abstract
Acyl(quinoxalin-2-yl)ketenes generated by thermal decarbonylation of 3-acylpyrrolo[1,2-a]quinoxaline-1,2,4(5H)-triones react regioselectively with Schiff bases under solvent-free conditions to form pyrimido[1,6-a]quinoxaline derivatives in good yields.
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Affiliation(s)
- Svetlana O Kasatkina
- Department of Chemistry, Perm State University, ul. Bukireva 15, Perm 614990, Russian Federation
| | - Ekaterina E Stepanova
- Department of Chemistry, Perm State University, ul. Bukireva 15, Perm 614990, Russian Federation
| | - Maksim V Dmitriev
- Department of Chemistry, Perm State University, ul. Bukireva 15, Perm 614990, Russian Federation
| | - Ivan G Mokrushin
- Department of Chemistry, Perm State University, ul. Bukireva 15, Perm 614990, Russian Federation
| | - Andrey N Maslivets
- Department of Chemistry, Perm State University, ul. Bukireva 15, Perm 614990, Russian Federation
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8
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Higgins GA, Zeeb FD, Fletcher PJ. Role of impulsivity and reward in the anti-obesity actions of 5-HT 2C receptor agonists. J Psychopharmacol 2017; 31:1403-1418. [PMID: 29072522 DOI: 10.1177/0269881117735797] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The selective 5-HT2C receptor agonist lorcaserin entered clinical obesity trials with the prevalent view that satiety was a primary mechanism of action. Subsequent Phase II and III trials demonstrated efficacy in terms of weight loss, although the overall effect size (~3% placebo-corrected change) is considered modest. Lorcaserin has been approved by the FDA for the treatment of obesity with lifestyle modification, but since its introduction in 2013 its sales are in decline, probably due to its overall modest effect. However, in some individuals, lorcaserin has a much more clinically significant effect (i.e. >10% placebo-corrected change), although what common features, if any, define these high responders is presently unknown. In the present article we highlight the evidence that alternative mechanisms to satiety may contribute to the anti-obesity effect of lorcaserin, namely effects on constructs of primary and conditioned reward and impulsivity. This may better inform the clinical evaluation of lorcaserin (and any future 5-HT2C receptor agonists) to subgroups of obese subjects characterized by overeating due to maladaptive impulsivity and reward mechanisms. One such population might be individuals diagnosed with binge eating disorder.
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Affiliation(s)
- Guy A Higgins
- 1 InterVivo Solutions Inc., Toronto, Canada.,2 Department of Pharmacology & Toxicology, University of Toronto, Toronto, Canada
| | - Fiona D Zeeb
- 3 Centre for Addiction and Mental Health, Toronto, Canada.,4 Department of Psychology & Psychiatry, University of Toronto, Toronto, Canada
| | - Paul J Fletcher
- 3 Centre for Addiction and Mental Health, Toronto, Canada.,4 Department of Psychology & Psychiatry, University of Toronto, Toronto, Canada
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9
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Valencia-Torres L, Olarte-Sánchez CM, Lyons DJ, Georgescu T, Greenwald-Yarnell M, Myers MG, Bradshaw CM, Heisler LK. Activation of Ventral Tegmental Area 5-HT 2C Receptors Reduces Incentive Motivation. Neuropsychopharmacology 2017; 42:1511-1521. [PMID: 27882999 PMCID: PMC5362069 DOI: 10.1038/npp.2016.264] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 11/01/2016] [Accepted: 11/16/2016] [Indexed: 11/20/2022]
Abstract
Obesity is primarily due to food intake in excess of the body's energetic requirements, intake that is not only associated with hunger but also the incentive value of food. The 5-hydroxytryptamine 2C receptor (5-HT2CR) is a target for the treatment of human obesity. Mechanistically, 5-HT2CRs are positioned to influence both homeostatic feeding circuits within the hypothalamus and reward circuits within the ventral tegmental area (VTA). Here we investigated the role of 5-HT2CRs in incentive motivation using a mathematical model of progressive ratio (PR) responding in mice. We found that the 5-HT2CR agonist lorcaserin significantly reduced both ad libitum chow intake and PR responding for chocolate pellets and increased c-fos expression in VTA 5-HT2CR expressing γ-aminobutyric acid (GABA) neurons, but not 5-HT2CR expressing dopamine (DA) neurons. We next adopted a chemogenetic approach using a 5-HT2CRCRE line to clarify the function of subset of 5-HT2C receptor expressing VTA neurons in the modulation of appetite and food-motivated behavior. Activation of VTA 5-HT2C receptor expressing neurons significantly reduced ad libitum chow intake, operant responding for chocolate pellets, and the incentive value of food. In contrast, chemogenetic inhibition of VTA 5-HT2C receptor expressing neurons had no effect on the feeding behavior. These results indicate that activation of the subpopulation of 5-HT2CR neurons within the VTA is sufficient to significantly reduce homeostatic feeding and effort-based intake of palatable food, and that this subset has an inhibitory role in motivational processes. These findings are relevant to the treatment of obesity.
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Affiliation(s)
- Lourdes Valencia-Torres
- Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, UK,Rowett Institute of Nutrition and Health, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK, Tel/Fax: +44 (0) 1224 438750, E-mail: or
| | | | - David J Lyons
- Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, UK
| | - Teodora Georgescu
- Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, UK
| | - Megan Greenwald-Yarnell
- Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Martin G Myers
- Division of Metabolism, Endocrinology, and Diabetes, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Christopher M Bradshaw
- Division of Psychiatry, University of Nottingham, Queen's Medical Centre, Nottingham, UK
| | - Lora K Heisler
- Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, UK,Rowett Institute of Nutrition and Health, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK, Tel/Fax: +44 (0) 1224 438750, E-mail: or
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10
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Di Giovanni G, De Deurwaerdère P. New therapeutic opportunities for 5-HT2C receptor ligands in neuropsychiatric disorders. Pharmacol Ther 2015; 157:125-62. [PMID: 26617215 DOI: 10.1016/j.pharmthera.2015.11.009] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The 5-HT2C receptor (R) displays a widespread distribution in the CNS and is involved in the action of 5-HT in all brain areas. Knowledge of its functional role in the CNS pathophysiology has been impaired for many years due to the lack of drugs capable of discriminating among 5-HT2R subtypes, and to a lesser extent to the 5-HT1B, 5-HT5, 5-HT6 and 5-HT7Rs. The situation has changed since the mid-90s due to the increased availability of new and selective synthesized compounds, the creation of 5-HT2C knock out mice, and the progress made in molecular biology. Many pharmacological classes of drugs including antipsychotics, antidepressants and anxiolytics display affinities toward 5-HT2CRs and new 5-HT2C ligands have been developed for various neuropsychiatric disorders. The 5-HT2CR is presumed to mediate tonic/constitutive and phasic controls on the activity of different central neurobiological networks. Preclinical data illustrate this complexity to a point that pharmaceutical companies developed either agonists or antagonists for the same disease. In order to better comprehend this complexity, this review will briefly describe the molecular pharmacology of 5-HT2CRs, as well as their cellular impacts in general, before addressing its central distribution in the mammalian brain. Thereafter, we review the preclinical efficacy of 5-HT2C ligands in numerous behavioral tests modeling human diseases, highlighting the multiple and competing actions of the 5-HT2CRs in neurobiological networks and monoaminergic systems. Notably, we will focus this evidence in the context of the physiopathology of psychiatric and neurological disorders including Parkinson's disease, levodopa-induced dyskinesia, and epilepsy.
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Affiliation(s)
- Giuseppe Di Giovanni
- Department of Physiology & Biochemistry, Faculty of Medicine and Surgery, University of Malta; Neuroscience Division, School of Biosciences, Cardiff University, Cardiff, UK.
| | - Philippe De Deurwaerdère
- Centre National de la Recherche Scientifique (Unité Mixte de Recherche 5293) 33076 Bordeaux Cedex, France.
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11
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Bauer CT, Banks ML, Blough BE, Negus SS. Role of 5-HT₂C receptors in effects of monoamine releasers on intracranial self-stimulation in rats. Psychopharmacology (Berl) 2015; 232:3249-58. [PMID: 26041338 PMCID: PMC4536134 DOI: 10.1007/s00213-015-3982-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 05/22/2015] [Indexed: 11/28/2022]
Abstract
RATIONALE Many monoamine releasers are abused by humans and produce abuse-related facilitation of intracranial self-stimulation (ICSS) in rats. Facilitation of ICSS in rats can be limited by monoamine releaser-induced serotonin (5-HT) release, but receptors that mediate 5-HT effects of monoamine releasers are unknown. OBJECTIVES The aim of this study is to investigate whether 5-HT2C receptor activation is necessary for rate-decreasing effects produced in an ICSS procedure in rats by the 5-HT-selective monoamine releaser fenfluramine and the non-selective releasers napthylisopropylamine (PAL-287) and (+)-3,4-methylenedioxymethamphetamine ((+)-MDMA). METHODS Adult male Sprague-Dawley rats with electrodes implanted in the medial forebrain bundle were trained to lever press for brain stimulation under a "frequency-rate" ICSS procedure. Effectiveness of the 5-HT2C antagonist SB 242,084 was evaluated to block rate-decreasing effects produced by (1) the 5-HT2C agonist Ro 60-0175, (2) the 5-HT-selective releaser fenfluramine, and (3) the mixed-action dopamine (DA)/norepinephrine (NE)/5-HT releasers PAL-287 (1.0-5.6 mg/kg) and (+)-MDMA (1.0-3.2 mg/kg). For comparison, effectiveness of SB 242,084 to alter rate-decreasing effects of the kappa-opioid receptor agonist U69,593 and rate-increasing effects of the DA>5-HT releaser amphetamine was also examined. RESULTS SB 242,084 pretreatment blocked rate-decreasing effects of Ro 60-0175 and fenfluramine, but not the rate-decreasing effects of U69,593 or the rate-increasing effects of amphetamine. SB 242,084 blunted the rate-decreasing effects and enhanced expression of rate-increasing effects of PAL-287 and (+)-MDMA. CONCLUSIONS These data suggest that 5-HT2C receptor activation contributes to rate-decreasing effects that are produced by selective and mixed-action 5-HT releasers in rats and that may oppose and limit the expression of abuse-related ICSS facilitation by these compounds.
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Affiliation(s)
- Clayton T. Bauer
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA USA
| | - Matthew L. Banks
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA USA
| | - Bruce E. Blough
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, NC USA
| | - S. Stevens Negus
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA USA
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12
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Zaniewska M, McCreary AC, Wydra K, Faron-Górecka A, Filip M. Context-controlled nicotine-induced changes in the labeling of serotonin (5-HT)2A and 5-HT2C receptors in the rat brain. Pharmacol Rep 2014; 67:451-9. [PMID: 25933953 DOI: 10.1016/j.pharep.2014.11.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 11/04/2014] [Accepted: 11/07/2014] [Indexed: 11/28/2022]
Abstract
BACKGROUND We have previously demonstrated that serotonin (5-HT)2A and 5-HT2C receptor ligands modulate the sensitizing effects of nicotine. In the present study we used male rats to verify the hypothesis that the binding pattern of 5-HT2A and 5-HT2C receptors in the brain is altered by chronic nicotine treatment in different environments. METHODS Rats were given repeatedly vehicle or nicotine in different sensitizing regimens (home or experimental cages). On day 10, animals were challenged with nicotine (expression of nicotine sensitization) or vehicle in either home or experimental cages, and were sacrificed immediately after the experiment. RESULTS Repeated treatment with nicotine in home cages evoked significant increases in [(3)H]ketanserin binding to 5-HT2A receptors in the prefrontal cortex, striatal subregions and ventral tegmental area as well as reductions in [(3)H]mesulergine binding to 5-HT2C receptors in subregions of the prefrontal cortex. In contrast, nicotine paired with environmental context produced robust increases in 5-HT2A receptor labeling in the infralimbic cortex and decreased [(3)H]ketanserin binding in striatal subregions and ventral tegmental area; 5-HT2C receptor labeling in the prefrontal cortex fell. CONCLUSIONS The present data indicate that chronic nicotine administration in home cages induces bi-directional neuroplastic changes within 5-HT2A and 5-HT2C receptors in the prefrontal cortex. Pairing the nicotine with environmental context potentiates the neuroplastic response in the latter region and evokes opposite changes in 5-HT2A receptor binding in striatal and tegmental regions compared with nicotine administered in the absence of the context, indicating a modulatory role of environmental context in the expression of nicotine-induced sensitization.
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Affiliation(s)
- Magdalena Zaniewska
- Laboratory of Drug Addiction Pharmacology, Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland.
| | | | - Karolina Wydra
- Laboratory of Drug Addiction Pharmacology, Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Agata Faron-Górecka
- Laboratory of Biochemical Pharmacology, Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Małgorzata Filip
- Laboratory of Drug Addiction Pharmacology, Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
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13
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The role of serotonin in drug use and addiction. Behav Brain Res 2014; 277:146-92. [PMID: 24769172 DOI: 10.1016/j.bbr.2014.04.007] [Citation(s) in RCA: 209] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 04/04/2014] [Accepted: 04/05/2014] [Indexed: 12/26/2022]
Abstract
The use of psychoactive drugs is a wide spread behaviour in human societies. The systematic use of a drug requires the establishment of different drug use-associated behaviours which need to be learned and controlled. However, controlled drug use may develop into compulsive drug use and addiction, a major psychiatric disorder with severe consequences for the individual and society. Here we review the role of the serotonergic (5-HT) system in the establishment of drug use-associated behaviours on the one hand and the transition and maintenance of addiction on the other hand for the drugs: cocaine, amphetamine, methamphetamine, MDMA (ecstasy), morphine/heroin, cannabis, alcohol, and nicotine. Results show a crucial, but distinct involvement of the 5-HT system in both processes with considerable overlap between psychostimulant and opioidergic drugs and alcohol. A new functional model suggests specific adaptations in the 5-HT system, which coincide with the establishment of controlled drug use-associated behaviours. These serotonergic adaptations render the nervous system susceptible to the transition to compulsive drug use behaviours and often overlap with genetic risk factors for addiction. Altogether we suggest a new trajectory by which serotonergic neuroadaptations induced by first drug exposure pave the way for the establishment of addiction.
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14
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McCool BA, Christian DT, Fetzer JA, Chappell AM. Lateral/basolateral amygdala serotonin type-2 receptors modulate operant self-administration of a sweetened ethanol solution via inhibition of principal neuron activity. Front Integr Neurosci 2014; 8:5. [PMID: 24523680 PMCID: PMC3906593 DOI: 10.3389/fnint.2014.00005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 01/09/2014] [Indexed: 11/13/2022] Open
Abstract
The lateral/basolateral amygdala (BLA) forms an integral part of the neural circuitry controlling innate anxiety and learned fear. More recently, BLA dependent modulation of self-administration behaviors suggests a much broader role in the regulation of reward evaluation. To test this, we employed a self-administration paradigm that procedurally segregates “seeking” (exemplified as lever-press behaviors) from consumption (drinking) directed at a sweetened ethanol solution. Microinjection of the nonselective serotonin type-2 receptor agonist, alpha-methyl-5-hydroxytryptamine (α-m5HT) into the BLA reduced lever pressing behaviors in a dose-dependent fashion. This was associated with a significant reduction in the number of response-bouts expressed during non-reinforced sessions without altering the size of a bout or the rate of responding. Conversely, intra-BLA α-m5HT only modestly effected consumption-related behaviors; the highest dose reduced the total time spent consuming a sweetened ethanol solution but did not inhibit the total number of licks, number of lick bouts, or amount of solution consumed during a session. In vitro neurophysiological characterization of BLA synaptic responses showed that α-m5HT significantly reduced extracellular field potentials. This was blocked by the 5-HT2A/C antagonist ketanserin suggesting that 5-HT2-like receptors mediate the behavioral effect of α-m5HT. During whole-cell patch current-clamp recordings, we subsequently found that α-m5HT increased action potential threshold and hyperpolarized the resting membrane potential of BLA pyramidal neurons. Together, our findings show that the activation of BLA 5-HT2A/C receptors inhibits behaviors related to reward-seeking by suppressing BLA principal neuron activity. These data are consistent with the hypothesis that the BLA modulates reward-related behaviors and provides specific insight into BLA contributions during operant self-administration of a sweetened ethanol solution.
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Affiliation(s)
- Brian A McCool
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem NC, USA
| | - Daniel T Christian
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem NC, USA
| | - Jonathan A Fetzer
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem NC, USA
| | - Ann M Chappell
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem NC, USA
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15
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Higgins GA, Sellers EM, Fletcher PJ. From obesity to substance abuse: therapeutic opportunities for 5-HT2C receptor agonists. Trends Pharmacol Sci 2013; 34:560-70. [PMID: 24041919 DOI: 10.1016/j.tips.2013.08.001] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 07/26/2013] [Accepted: 08/02/2013] [Indexed: 12/25/2022]
Abstract
The recent US Food and Drug Administration (FDA) approval of the serotonin (5-hydroxytryptamine, 5-HT) 5-HT2C receptor agonist lorcaserin for the treatment of obesity represents a new therapeutic drug class available to the clinic. Preclinical evidence supports the potential for this drug class to treat other related conditions such as substance abuse. In the present article we review this evidence and further suggest that overlapping neurobiological systems may contribute to an anti-addictive and anti-obesity profile. The availability of selective 5-HT2C agonists provides an opportunity to evaluate their potential as treatments for nicotine dependence or psychostimulant abuse, conditions for which there is significant medical need but only limited available treatment options.
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Affiliation(s)
- Guy A Higgins
- InterVivo Solutions Inc, 120 Carlton Street, Toronto, ON M5A 4K2, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada.
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Nakamura K. The role of the dorsal raphé nucleus in reward-seeking behavior. Front Integr Neurosci 2013; 7:60. [PMID: 23986662 PMCID: PMC3753458 DOI: 10.3389/fnint.2013.00060] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2013] [Accepted: 07/30/2013] [Indexed: 12/22/2022] Open
Abstract
Pharmacological experiments have shown that the modulation of brain serotonin levels has a strong impact on value-based decision making. Anatomical and physiological evidence also revealed that the dorsal raphé nucleus (DRN), a major source of serotonin, and the dopamine system receive common inputs from brain regions associated with appetitive and aversive information processing. The serotonin and dopamine systems also have reciprocal functional influences on each other. However, the specific mechanism by which serotonin affects value-based decision making is not clear. To understand the information carried by the DRN for reward-seeking behavior, we measured single neuron activity in the primate DRN during the performance of saccade tasks to obtain different amounts of a reward. We found that DRN neuronal activity was characterized by tonic modulation that was altered by the expected and received reward value. Consistent reward-dependent modulation across different task periods suggested that DRN activity kept track of the reward value throughout a trial. The DRN was also characterized by modulation of its activity in the opposite direction by different neuronal subgroups, one firing strongly for the prediction and receipt of large rewards, with the other firing strongly for small rewards. Conversely, putative dopamine neurons showed positive phasic responses to reward-indicating cues and the receipt of an unexpected reward amount, which supports the reward prediction error signal hypothesis of dopamine. I suggest that the tonic reward monitoring signal of the DRN, possibly together with its interaction with the dopamine system, reports a continuous level of motivation throughout the performance of a task. Such a signal may provide "reward context" information to the targets of DRN projections, where it may be integrated further with incoming motivationally salient information.
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Affiliation(s)
- Kae Nakamura
- Department of Physiology, Kansai Medical University Hirakata, Japan ; Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency Kawaguchi, Japan
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17
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Cohen A, George O. Animal models of nicotine exposure: relevance to second-hand smoking, electronic cigarette use, and compulsive smoking. Front Psychiatry 2013; 4:41. [PMID: 23761766 PMCID: PMC3671664 DOI: 10.3389/fpsyt.2013.00041] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 05/13/2013] [Indexed: 12/23/2022] Open
Abstract
Much evidence indicates that individuals use tobacco primarily to experience the psychopharmacological properties of nicotine and that a large proportion of smokers eventually become dependent on nicotine. In humans, nicotine acutely produces positive reinforcing effects, including mild euphoria, whereas a nicotine abstinence syndrome with both somatic and affective components is observed after chronic nicotine exposure. Animal models of nicotine self-administration and chronic exposure to nicotine have been critical in unveiling the neurobiological substrates that mediate the acute reinforcing effects of nicotine and emergence of a withdrawal syndrome during abstinence. However, important aspects of the transition from nicotine abuse to nicotine dependence, such as the emergence of increased motivation and compulsive nicotine intake following repeated exposure to the drug, have only recently begun to be modeled in animals. Thus, the neurobiological mechanisms that are involved in these important aspects of nicotine addiction remain largely unknown. In this review, we describe the different animal models available to date and discuss recent advances in animal models of nicotine exposure and nicotine dependence. This review demonstrates that novel animal models of nicotine vapor exposure and escalation of nicotine intake provide a unique opportunity to investigate the neurobiological effects of second-hand nicotine exposure, electronic cigarette use, and the mechanisms that underlie the transition from nicotine use to compulsive nicotine intake.
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Affiliation(s)
- Ami Cohen
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA, USA
| | - Olivier George
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA, USA
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18
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The 5-HT2C receptor agonist lorcaserin reduces nicotine self-administration, discrimination, and reinstatement: relationship to feeding behavior and impulse control. Neuropsychopharmacology 2012; 37:1177-91. [PMID: 22189292 PMCID: PMC3306879 DOI: 10.1038/npp.2011.303] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Lorcaserin ((1R)-8-chloro-1-methyl-2,3,4,5-tetrahydro-1H-3-benzazepine HCl) is a selective 5-HT(2C) receptor agonist with clinical efficacy in phase-III obesity trials. Based on evidence that this drug class also affects behaviors motivated by drug reinforcement, we compared the effect of lorcaserin on behavior maintained by food and nicotine reinforcement, as well as the stimulant and discriminative stimulus properties of nicotine in the rat. Acutely administered lorcaserin (0.3-3 mg/kg, subcutaneous (SC)) dose dependently reduced feeding induced by 22-h food deprivation or palatability. Effects up to 1 mg/kg were consistent with a specific effect on feeding motivation. Lorcaserin (0.6-1 mg/kg, SC) reduced operant responding for food on progressive and fixed ratio schedules of reinforcement. In this dose range lorcaserin also reversed the motor stimulant effect of nicotine, reduced intravenous self-administration of nicotine, and attenuated the nicotine cue in rats trained to discriminate nicotine from saline. Lorcaserin also reduced the reinstatement of nicotine-seeking behavior elicited by a compound cue comprising a nicotine prime and conditioned stimulus previously paired with nicotine reinforcement. Lorcaserin did not reinstate nicotine-seeking behavior or substitute for a nicotine cue. Finally, lorcaserin (0.3-1 mg/kg) reduced nicotine-induced increases in anticipatory responding, a measure of impulsive action, in rats performing the five-choice serial reaction time task. Importantly, these results indicate that lorcaserin, and likely other selective 5-HT(2C) receptor agonists, similarly affect both food- and nicotine-motivated behaviors, and nicotine-induced impulsivity. Collectively, these findings highlight a therapeutic potential for 5-HT(2C) agonists such as lorcaserin beyond obesity into addictive behaviors, such as nicotine dependence.
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Pharmacological and genetic interventions in serotonin (5-HT)(2C) receptors to alter drug abuse and dependence processes. Brain Res 2012; 1476:132-53. [PMID: 22494568 DOI: 10.1016/j.brainres.2012.03.035] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Revised: 03/13/2012] [Accepted: 03/15/2012] [Indexed: 11/22/2022]
Abstract
The present review provides an overview on serotonin (5-hydroxytryptamine; 5-HT)(2C) receptors and their relationship to drug dependence. We have focused our discussion on the impact of 5-HT(2C) receptors on the effects of different classes of addictive drugs, illustrated by reference to data using pharmacological and genetic tools. The neurochemical mechanism of the interaction between 5-HT(2C) receptors, with focus on the mesocorticolimbic dopaminergic system, and drugs of abuse (using cocaine as an example) is discussed. Finally, we integrate recent nonclinical and clinical research and information with marketed products possessing 5-HT(2C) receptor binding affinities. Accordingly, available nonclinical data and some clinical observations targeting 5-HT(2C) receptors may offer innovative translational strategies for combating drug dependence.This article is part of a Special Issue entitled: Brain Integration.
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Fletcher PJ, Rizos Z, Noble K, Soko AD, Silenieks LB, Lê AD, Higgins GA. Effects of the 5-HT2C receptor agonist Ro60-0175 and the 5-HT2A receptor antagonist M100907 on nicotine self-administration and reinstatement. Neuropharmacology 2012; 62:2288-98. [PMID: 22342986 DOI: 10.1016/j.neuropharm.2012.01.023] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 01/22/2012] [Accepted: 01/28/2012] [Indexed: 12/12/2022]
Abstract
The reinforcing effects of nicotine are mediated in part by brain dopamine systems. Serotonin, acting via 5-HT(2A) and 5-HT(2C) receptors, modulates dopamine function. In these experiments we examined the effects of the 5-HT(2C) receptor agonist Ro60-0175 and the 5-HT(2A) receptor antagonist (M100907, volinanserin) on nicotine self-administration and reinstatement of nicotine-seeking. Male Long-Evans rats self-administered nicotine (0.03 mg/kg/infusion, IV) on either a FR5 or a progressive ratio schedule of reinforcement. Ro60-0175 reduced responding for nicotine on both schedules. While Ro60-0175 also reduced responding for food reinforcement, response rates under drug treatment were several-fold higher than in animals responding for nicotine. M100907 did not alter responding for nicotine, or food, on either schedule. In tests of reinstatement of nicotine-seeking, rats were first trained to lever press for IV infusions of nicotine; each infusion was also accompanied by a compound cue consisting of a light and tone. This response was then extinguished over multiple sessions. Injecting rats with a nicotine prime (0.15 mg/kg) reinstated responding; reinstatement was also observed when responses were accompanied by the nicotine associated cue. Ro60-0175 attenuated reinstatement of responding induced by nicotine and by the cue. The effects of Ro60-0175 on both forms of reinstatement were blocked by the 5-HT(2C) receptor antagonist SB242084. M100907 also reduced reinstatement induced by either the nicotine prime or by the nicotine associated cue. The results indicate that 5-HT(2C) and 5-HT(2A) receptors may be potential targets for therapies to treat some aspects of nicotine dependence.
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Affiliation(s)
- Paul J Fletcher
- Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T 1R8, Canada.
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21
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Hayes DJ, Hoang J, Greenshaw AJ. The role of nucleus accumbens shell GABA receptors on ventral tegmental area intracranial self-stimulation and a potential role for the 5-HT(2C) receptor. J Psychopharmacol 2011; 25:1661-75. [PMID: 21169393 DOI: 10.1177/0269881110389212] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Brain γ-aminobutyric acid (GABA) and 5-hydroxytryptamine (5-HT)(2C) receptors are implicated in the neuronal regulation of reward- and aversion-related behaviour. Within the mesocorticolimbic pathways of the brain, relationships between GABA containing neurons and 5-HT(2C) receptor activity may be important in this context. The primary aim of this study was to investigate the role of NAc shell GABA receptors on ventral tegmental area intracranial self-stimulation (ICSS) and to examine the systemic effects of GABAergic ligands in this context. The second aim was to investigate the relationship between GABA receptor- and 5-HT(2C) receptor-related ICSS behaviour, using systemic administration of the selective agonist WAY 161503. Locomotor activity was assessed to compare the potential motor effects of drugs; feeding behaviour and intra-NAc injections of amphetamine (1.0 µg/side) were used as positive controls. When administered systemically the GABA(A) receptor agonist muscimol and antagonist picrotoxin did not selectively change ICSS reward thresholds, although the 5-HT(2C) receptor agonist WAY 161503 (1.0 mg/kg) decreased reward measures. Intra-NAc shell administration of muscimol (225 ng/side) and picrotoxin (125 ng/side), respectively, decreased and increased measures of reward. Intra-NAc shell baclofen (0-225 ng/side; GABA(B) receptor agonist) did not affect any ICSS measures although it increased feeding. Combining picrotoxin and WAY 161503 attenuated the effects of each. These results suggest that a 5-HT(2C) and GABA(A) receptor-mediated neuronal relationship in the NAc shell may be relevant for the regulation of brain reward pathways.
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Affiliation(s)
- Dave J Hayes
- Centre for Neuroscience, University of Alberta, Edmonton, AB, Canada.
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Hayes DJ, Greenshaw AJ. 5-HT receptors and reward-related behaviour: a review. Neurosci Biobehav Rev 2011; 35:1419-49. [PMID: 21402098 DOI: 10.1016/j.neubiorev.2011.03.005] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Revised: 03/03/2011] [Accepted: 03/04/2011] [Indexed: 01/07/2023]
Abstract
The brain's serotonin (5-HT) system is key in the regulation of reward-related behaviours, from eating and drinking to sexual activity. The complexity of studying this system is due, in part, to the fact that 5-HT acts at many receptor subtypes throughout the brain. The recent development of drugs with greater selectivity for individual receptor subtypes has allowed for rapid advancements in our understanding of this system. Use of these drugs in combination with animal models entailing selective reward measures (i.e. intracranial self-stimulation, drug self-administration, conditioned place preference) have resulted in a greater understanding of the pharmacology of reward-related processing and behaviour (particularly regarding drugs of abuse). The putative roles of each 5-HT receptor subtype in the pharmacology of reward are outlined and discussed here. It is concluded that the actions of 5-HT in reward are receptor subtype-dependent (and thus should not be generalized) and that all studied subtypes appear to have a unique profile which is determined by content (e.g. receptor function, localization - both throughout the brain and within the synapse) and context (e.g. type of behavioural paradigm, type of drug). Given evidence of altered reward-related processing and serotonergic function in numerous neuropsychiatric disorders, such as depression, schizophrenia, and addiction, a clearer understanding of the role of 5-HT receptor subtypes in this context may lead to improved drug development and therapeutic approaches.
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Affiliation(s)
- Dave J Hayes
- Centre for Neuroscience, 513 HMRC, University of Alberta, Edmonton, AB, T6G 2S2, Canada.
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Katsidoni V, Apazoglou K, Panagis G. Role of serotonin 5-HT2A and 5-HT2C receptors on brain stimulation reward and the reward-facilitating effect of cocaine. Psychopharmacology (Berl) 2011; 213:337-54. [PMID: 20577718 DOI: 10.1007/s00213-010-1887-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Accepted: 03/27/2010] [Indexed: 01/20/2023]
Abstract
RATIONALE The serotonin 5-HT(2A) and 5-HT(2C) receptors, which are found in abundance in the mesolimbocortical dopaminergic system, appear to modulate the behavioral effects of cocaine. OBJECTIVES The present series of studies set out to investigate the role of 5-HT(2A) and 5-HT(2C) receptors on brain reward and on the reward-facilitating effect of cocaine and localize the neural substrates within the mesolimbocortical dopaminergic system that are responsible for these effects. METHODS Male Sprague-Dawley rats were implanted with stimulating electrodes and bilateral cannulae for the experiments involving microinjections and were trained to respond to electrical stimulation. In the first study, we examined the effects of systemic administration of selective 5-HT(2A) and 5-HT(2C) receptor agonists (TCB-2 and WAY-161503) and antagonists (R-96544 and SB-242084) on intracranial self-stimulation (ICSS). In the second study, we examined the effectiveness of TCB-2, WAY-161503, R-96544, and SB-242084 in blocking the reward-facilitating effect of cocaine. In the third study, we examined the effects of intra-medial prefrontal cortex (mPFC), intra-nucleus accumbens (NAC), and intra-ventral tegmental area (VTA) injection of WAY-161503 on the reward-facilitating effect of cocaine. RESULTS Acute systemic administration of TCB-2 and WAY-161503 increased ICSS threshold. Systemic WAY-161503 attenuated the reward-facilitating effect of cocaine. This effect was reversed by pretreatment with SB-242084. Intracranial microinjections of WAY-161503 into the mPFC and the NAC shell/core, but not the VTA, attenuated the reward-facilitating effect of cocaine. CONCLUSION These data indicate that 5-HT(2C) receptors within the mPFC and the NAC modulate the reinforcing effects of cocaine and provide evidence that 5-HT(2C) receptor agonists could be a possible drug discovery target for the treatment of psychostimulant addiction.
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Affiliation(s)
- Vicky Katsidoni
- Department of Psychology, School of Social Sciences, University of Crete, Rethymno, Crete, Greece
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Hernandez G, Breton YA, Conover K, Shizgal P. At what stage of neural processing does cocaine act to boost pursuit of rewards? PLoS One 2010; 5:e15081. [PMID: 21152097 PMCID: PMC2994896 DOI: 10.1371/journal.pone.0015081] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Accepted: 10/15/2010] [Indexed: 11/25/2022] Open
Abstract
Dopamine-containing neurons have been implicated in reward and decision making. One element of the supporting evidence is that cocaine, like other drugs that increase dopaminergic neurotransmission, powerfully potentiates reward seeking. We analyze this phenomenon from a novel perspective, introducing a new conceptual framework and new methodology for determining the stage(s) of neural processing at which drugs, lesions and physiological manipulations act to influence reward-seeking behavior. Cocaine strongly boosts the proclivity of rats to work for rewarding electrical brain stimulation. We show that the conventional conceptual framework and methods do not distinguish between three conflicting accounts of how the drug produces this effect: increased sensitivity of brain reward circuitry, increased gain, or decreased subjective reward costs. Sensitivity determines the stimulation strength required to produce a reward of a given intensity (a measure analogous to the KM of an enzyme) whereas gain determines the maximum intensity attainable (a measure analogous to the vmax of an enzyme-catalyzed reaction). To distinguish sensitivity changes from the other determinants, we measured and modeled reward seeking as a function of both stimulation strength and opportunity cost. The principal effect of cocaine was a two-fourfold increase in willingness to pay for the electrical reward, an effect consistent with increased gain or decreased subjective cost. This finding challenges the long-standing view that cocaine increases the sensitivity of brain reward circuitry. We discuss the implications of the results and the analytic approach for theories of how dopaminergic neurons and other diffuse modulatory brain systems contribute to reward pursuit, and we explore the implications of the conceptual framework for the study of natural rewards, drug reward, and mood.
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Affiliation(s)
- Giovanni Hernandez
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Yannick-André Breton
- Center for Studies in Behavioral Neurobiology, Concordia University, Montréal, Québec, Canada
| | - Kent Conover
- Center for Studies in Behavioral Neurobiology, Concordia University, Montréal, Québec, Canada
| | - Peter Shizgal
- Center for Studies in Behavioral Neurobiology, Concordia University, Montréal, Québec, Canada
- * E-mail:
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Berrendero F, Robledo P, Trigo JM, Martín-García E, Maldonado R. Neurobiological mechanisms involved in nicotine dependence and reward: participation of the endogenous opioid system. Neurosci Biobehav Rev 2010; 35:220-31. [PMID: 20170672 PMCID: PMC2908214 DOI: 10.1016/j.neubiorev.2010.02.006] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2009] [Revised: 02/08/2010] [Accepted: 02/09/2010] [Indexed: 01/07/2023]
Abstract
Nicotine is the primary component of tobacco that maintains the smoking habit and develops addiction. The adaptive changes of nicotinic acetylcholine receptors produced by repeated exposure to nicotine play a crucial role in the establishment of dependence. However, other neurochemical systems also participate in the addictive effects of nicotine including glutamate, cannabinoids, GABA and opioids. This review will cover the involvement of these neurotransmitters in nicotine addictive properties, with a special emphasis on the endogenous opioid system. Thus, endogenous enkephalins and beta-endorphins acting on mu-opioid receptors are involved in nicotine-rewarding effects, whereas opioid peptides derived from prodynorphin participate in nicotine aversive responses. An up-regulation of mu-opioid receptors has been reported after chronic nicotine treatment that could counteract the development of nicotine tolerance, whereas the down-regulation induced on kappa-opioid receptors seems to facilitate nicotine tolerance. Endogenous enkephalins acting on mu-opioid receptors also play a role in the development of physical dependence to nicotine. In agreement with these actions of the endogenous opioid system, the opioid antagonist naltrexone has shown to be effective for smoking cessation in certain sub-populations of smokers.
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Affiliation(s)
- Fernando Berrendero
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, University Pompeu Fabra, PRBB, C/Doctor Aiguader 88, 08003 Barcelona, Spain
| | - Patricia Robledo
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, University Pompeu Fabra, PRBB, C/Doctor Aiguader 88, 08003 Barcelona, Spain
- Municipal Institute of Medical Research (IMIM), Barcelona, Spain
| | - José Manuel Trigo
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, University Pompeu Fabra, PRBB, C/Doctor Aiguader 88, 08003 Barcelona, Spain
| | - Elena Martín-García
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, University Pompeu Fabra, PRBB, C/Doctor Aiguader 88, 08003 Barcelona, Spain
| | - Rafael Maldonado
- Laboratory of Neuropharmacology, Department of Experimental and Health Sciences, University Pompeu Fabra, PRBB, C/Doctor Aiguader 88, 08003 Barcelona, Spain
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Zaniewska M, McCreary AC, Wydra K, Filip M. Differential effects of serotonin (5-HT)2 receptor-targeting ligands on locomotor responses to nicotine-repeated treatment. Synapse 2010; 64:511-9. [PMID: 20196140 DOI: 10.1002/syn.20756] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We verified the hypothesis that serotonin (5-HT)(2) receptors control the locomotor effects of nicotine (0.4 mg kg(-1)) in rats by using the 5-HT(2A) receptor antagonist M100907, the preferential 5-HT(2A) receptor agonist DOI, the 5-HT(2C) receptor antagonist SB 242084, and the 5-HT(2C) receptor agonists Ro 60-0175 and WAY 163909. Repeated pairings of a test environment with nicotine for 5 days, on Day 10 significantly augmented the locomotor activity following nicotine administration. Of the investigated 5-HT(2) receptor ligands, M100907 (2 mg kg(-1)) or DOI (1 mg kg(-1)) administered during the first 5 days in combination with nicotine attenuated or enhanced, respectively, the development of nicotine sensitization. Given acutely on Day 10, M100907 (2 mg kg(-1)), Ro 60-0175 (1 mg kg(-1)), and WAY 163909 (1.5 mg kg(-1)) decreased the expression of nicotine sensitization. In another set of experiments, where the nicotine challenge test was performed on Day 15 in animals treated repeatedly (Days: 1-5, 10) with nicotine, none of 5-HT(2) receptor ligands administered during the second withdrawal period (Days: 11-14) to nicotine-treated rats altered the sensitizing effect of nicotine given on Day 15. Our data indicate that 5-HT(2A) receptors (but not 5-HT(2C) receptors) play a permissive role in the sensitizing effects of nicotine, while stimulation of 5-HT(2A) receptors enhances the development of nicotine sensitization and activation of 5-HT(2C) receptors is essential for the expression of nicotine sensitization. Repeated treatment with the 5-HT(2) receptor ligands within the second nicotine withdrawal does not inhibit previously established sensitization.
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Affiliation(s)
- Magdalena Zaniewska
- Laboratory of Drug Addiction Pharmacology, Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, 31-343 Kraków, Poland.
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27
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Zaniewska M, McCreary AC, Wydra K, Filip M. Effects of serotonin (5-HT)2 receptor ligands on depression-like behavior during nicotine withdrawal. Neuropharmacology 2010; 58:1140-6. [PMID: 20153341 DOI: 10.1016/j.neuropharm.2010.02.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 02/03/2010] [Accepted: 02/07/2010] [Indexed: 11/29/2022]
Abstract
A pronounced withdrawal syndrome including depressed mood prevents cigarette smoking cessation. We tested if blockade or activation of serotonin (5-HT)(2) receptors affected the time of immobility (as an indirect measure of depression-like behavior) in naïve animals and in those withdrawn from chronic nicotine in the forced swim test (FST). The antidepressant imipramine was used as a control. In the FST, the selective 5-HT(2A) receptor antagonist M100,907 (1-2 mg/kg, but not 0.5 mg/kg), the selective 5-HT(2C) receptor antagonist SB 242,084 (0.3-1 mg/kg, but not 0.1 mg/kg), the 5-HT(2C) receptor agonists Ro 60-0175 (10 mg/kg, but not 3 mg/kg) and WAY 163,909 (1.5-10 mg/kg, but not 0.75 mg/kg) as well as imipramine (30 mg/kg, but not 15 mg/kg) decreased the immobility time while the non-selective 5-HT(2) receptor agonist DOI (0.1-1 mg/kg) was inactive in naïve rats. We found an increase in immobility time in rats that were withdrawn from nicotine exposure after 5 days of chronic nicotine treatment. This effect increased from day 1 until day 10 following withdrawal of nicotine, with maximal withdrawal effects on day 3. M100,907 (1 mg/kg), SB 242,084 (0.3 mg/kg), Ro 60-0175 (3 mg/kg), WAY 163,909 (0.75-1.5 mg/kg) and imipramine (15-30 mg/kg) shortened the immobility time in rats that had been removed from nicotine exposure for 3 days. Locomotor activity studies indicated that the effects of SB 242,084 might have been non-specific, as we noticed enhanced basal locomotion in naïve rats. This data set demonstrates that 5-HT(2A) receptor antagonist and 5-HT(2C) receptor agonists exhibited effects similar to antidepressant drugs and abolished the depression-like effects in nicotine-withdrawn rats. These drugs should be considered as adjuncts to smoking cessation therapy, to ameliorate abstinence-induced depressive symptoms.
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Affiliation(s)
- Magdalena Zaniewska
- Laboratory of Drug Addiction Pharmacology, Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, 31-343 Kraków, Poland.
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Noorbakhsh F, Ramachandran R, Barsby N, Ellestad KK, LeBlanc A, Dickie P, Baker G, Hollenberg MD, Cohen EA, Power C. MicroRNA profiling reveals new aspects of HIV neurodegeneration: caspase-6 regulates astrocyte survival. FASEB J 2010; 24:1799-812. [PMID: 20097875 DOI: 10.1096/fj.09-147819] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
MicroRNAs (miRNAs) are small noncoding RNA molecules, which are known to regulate gene expression in physiological and pathological conditions. miRNA profiling was performed using brain tissue from patients with HIV encephalitis (HIVE), a neuroinflammatory/degenerative disorder caused by HIV infection of the brain. Microarray analysis showed differential expression of multiple miRNAs in HIVE compared to control brains. Target prediction and gene ontology enrichment analysis disclosed targeting of several gene families/biological processes by differentially expressed miRNAs (DEMs), with cell death-related genes, including caspase-6, showing a bias toward down-regulated DEMs. Consistent with the miRNA data, HIVE brains exhibited higher levels of caspase-6 transcripts compared with control patients. Immunohistochemical analysis showed localization of the cleaved form of caspase-6 in astrocytes in HIVE brain sections. Exposure of cultured human primary astrocytes to HIV viral protein R (Vpr) induced p53 up-regulation, loss of mitochondrial membrane potential, and caspase-6 activation followed by cell injury. Transgenic mice, expressing Vpr in microglial cells, demonstrated astrocyte apoptosis in brain, which was associated with caspase-6 activation and neurobehavioral abnormalities. Overall, these data point to previously unrecognized alterations in miRNA profile in the brain during HIV infection, which contribute to cell death through dysregulation of cell death machinery.
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Affiliation(s)
- Farshid Noorbakhsh
- Department of Medicine (Neurology), University of Alberta, Edmonton, AB, Canada
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Jupp B, Lawrence AJ. New horizons for therapeutics in drug and alcohol abuse. Pharmacol Ther 2010; 125:138-68. [DOI: 10.1016/j.pharmthera.2009.11.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Accepted: 11/03/2009] [Indexed: 11/25/2022]
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Hayes DJ, Clements R, Greenshaw AJ. Effects of systemic and intra-nucleus accumbens 5-HT2C receptor compounds on ventral tegmental area self-stimulation thresholds in rats. Psychopharmacology (Berl) 2009; 203:579-88. [PMID: 19031071 DOI: 10.1007/s00213-008-1404-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Accepted: 10/29/2008] [Indexed: 11/29/2022]
Abstract
RATIONALE Serotonin 2C (5-HT(2C)) receptors may play a role in regulating motivation and reward-related behaviours. To date, no studies have investigated the possible role of 5-HT(2C) receptors in ventral tegmental area (VTA) intracranial self-stimulation (ICSS). OBJECTIVES The current study investigated the hypotheses that 5-HT(2C) receptors play an inhibitory role in VTA ICSS, and that 5-HT(2C) receptors within the nucleus accumbens (NAc) shell may be involved. METHODS Male Sprague-Dawley rats were implanted with a VTA electrode and bilateral NAc shell cannulae for the experiment involving microinjections, and trained to respond for electrical self-stimulation. The systemic effects of the selective 5-HT(2C) receptor agonist WAY 161503 (0-1.0 mg/kg), the 5-HT(1A/1B/2C) receptor agonist TFMPP (0.3 mg/kg) and the selective 5-HT(2C) receptor antagonist SB 242084 (1.0 mg/kg) were compared using rate-frequency threshold analysis. Intra-NAc shell microinjections of WAY 161503 (0-1.5 microg/side) were investigated and compared to amphetamine (1.0 microg/side). RESULTS WAY 161503 (1.0 mg/kg) and TFMPP (0.3 mg/kg) significantly increased rate-frequency thresholds (M50 values) without altering maximal response rates (RMAX values). SB 242084 attenuated the effects of TFMPP; SB 242084 had no affect on M50 or RMAX values. Intra-NAc shell WAY 161503 had no effect on M50 or RMAX values; intra-NAc amphetamine decreased M50 values. CONCLUSIONS These results suggest that 5-HT(2C) receptors play an inhibitory role in regulating reward-related behaviour while 5-HT(2C) receptor activation in the NAc shell did not appear to influence VTA ICSS behaviour under the present experimental conditions.
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Affiliation(s)
- Dave J Hayes
- Centre for Neuroscience, 513 HMRC, University of Alberta, Edmonton, AB, Canada T6G 2S2
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