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Heifets BD, Olson DE. Therapeutic mechanisms of psychedelics and entactogens. Neuropsychopharmacology 2024; 49:104-118. [PMID: 37488282 PMCID: PMC10700553 DOI: 10.1038/s41386-023-01666-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 07/10/2023] [Accepted: 07/11/2023] [Indexed: 07/26/2023]
Abstract
Recent clinical and preclinical evidence suggests that psychedelics and entactogens may produce both rapid and sustained therapeutic effects across several indications. Currently, there is a disconnect between how these compounds are used in the clinic and how they are studied in preclinical species, which has led to a gap in our mechanistic understanding of how these compounds might positively impact mental health. Human studies have emphasized extra-pharmacological factors that could modulate psychedelic-induced therapeutic responses including set, setting, and integration-factors that are poorly modelled in current animal experiments. In contrast, animal studies have focused on changes in neuronal activation and structural plasticity-outcomes that are challenging to measure in humans. Here, we describe several hypotheses that might explain how psychedelics rescue neuropsychiatric disease symptoms, and we propose ways to bridge the gap between human and rodent studies. Given the diverse pharmacological profiles of psychedelics and entactogens, we suggest that their rapid and sustained therapeutic mechanisms of action might best be described by the collection of circuits that they modulate rather than their actions at any single molecular target. Thus, approaches focusing on selective circuit modulation of behavioral phenotypes might prove more fruitful than target-based methods for identifying novel compounds with rapid and sustained therapeutic effects similar to psychedelics and entactogens.
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Affiliation(s)
- Boris D Heifets
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Stanford, CA, 94305, USA.
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, 94305, USA.
| | - David E Olson
- Institute for Psychedelics and Neurotherapeutics, University of California, Davis, Davis, CA, 95616, USA.
- Department of Chemistry, University of California, Davis, Davis, CA, 95616, USA.
- Center for Neuroscience, University of California, Davis, Davis, CA, 95618, USA.
- Department of Biochemistry and Molecular Medicine, School of Medicine, University of California, Davis, Sacramento, CA, 95817, USA.
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Serotonin 2C Antagonism in the Lateral Orbitofrontal Cortex Ameliorates Cue-Enhanced Risk Preference and Restores Sensitivity to Reinforcer Devaluation in Male Rats. eNeuro 2021; 8:ENEURO.0341-21.2021. [PMID: 34815296 PMCID: PMC8670605 DOI: 10.1523/eneuro.0341-21.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 10/27/2021] [Accepted: 11/16/2021] [Indexed: 11/21/2022] Open
Abstract
Previous research has indicated that reward-paired cues can enhance disadvantageous risky choice in both humans and rodents. Systemic administration of a serotonin 2C receptor antagonist can attenuate this cue-induced risk preference in rats. However, the neurocognitive mechanisms mediating this effect are currently unknown. We therefore assessed whether the serotonin 2C receptor antagonist RS 102221 is able to attenuate cue-enhanced risk preference via its actions in the lateral orbitofrontal cortex (lOFC) or prelimbic (PrL) area of the medial prefrontal cortex (mPFC). A total of 32 male Long–Evans rats were trained on the cued version of the rat gambling task (rGT), a rodent analog of the human Iowa gambling task, and bilateral guide cannulae were implanted into the lOFC or PrL. Intra-lOFC infusions of the 5-HT2C antagonist RS 102221 reduced risky choice in animals that showed a preference for the risky options of the rGT at baseline. This effect was not observed in optimal decision-makers, nor those that received infusions targeting the PrL. Given prior data showing that 5-HT2C antagonists also improve reversal learning through the same neural locus, we hypothesized that reward-concurrent cues may amplify risky decision-making through cognitive inflexibility. We therefore devalued the sugar pellet rewards used in the cued rGT (crGT) through satiation and observed that decision-making patterns did not shift unless animals also received intra-lOFC RS 102221. Collectively, these data suggest that the lOFC is one critical site through which reward-concurrent cues promote risky choice patterns that are insensitive to reinforcer devaluation, and that 5-HT2C antagonism may optimize choice by facilitating exploration.
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Cathala A, Devroye C, Robert É, Vallée M, Revest JM, Artigas F, Spampinato U. Serotonin2B receptor blockade in the rat dorsal raphe nucleus suppresses cocaine-induced hyperlocomotion through an opposite control of mesocortical and mesoaccumbens dopamine pathways. Neuropharmacology 2020; 180:108309. [DOI: 10.1016/j.neuropharm.2020.108309] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/09/2020] [Accepted: 09/14/2020] [Indexed: 12/22/2022]
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Ruiz-Sánchez E, Pedraza-Chaverri J, Medina-Campos ON, Maldonado PD, Rojas P. S-allyl Cysteine, a Garlic Compound, Produces an Antidepressant-Like Effect and Exhibits Antioxidant Properties in Mice. Brain Sci 2020; 10:brainsci10090592. [PMID: 32859119 PMCID: PMC7564461 DOI: 10.3390/brainsci10090592] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/20/2020] [Accepted: 08/24/2020] [Indexed: 12/15/2022] Open
Abstract
Depression is a psychiatric disorder, and oxidative stress is a significant mechanism of damage in this mood disorder. It is characterized by an enhancement of oxidative stress markers and low concentrations of endogenous antioxidants, or antioxidants enzymes. This suggests that antioxidants could have an antidepressant effect. S-allyl cysteine (SAC) is a compound with antioxidant action or free radical scavenger capacity. The purpose of the current research was to evaluate the antidepressant-like effect as well as the antioxidant role of SAC on a preclinical test, using the Porsolt forced swim test (FST). SAC (30, 70, 120, or 250 mg/kg, ip) was administered to male BALB/c mice daily for 17 days, followed by the FST at day 18. Oxidative stress markers (reactive oxygen species, superoxide production, lipid peroxidation, and antioxidant enzymes activities) were analyzed in the midbrain, prefrontal cortex, and hippocampus. SAC (120 mg/kg) attenuated the immobility scores (44%) in the FST, and protection was unrelated to changes in locomotor activity. This antidepressant-like effect was related to decreased oxidative stress, as indicated by lipid peroxidation and manganese-superoxide dismutase (Mn-SOD) activity in the hippocampus. SAC exerts an antidepressant-like effect that correlated, in part, with preventing oxidative damage in hippocampus.
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Affiliation(s)
- Elizabeth Ruiz-Sánchez
- Laboratory of Neurotoxicology, National Institute of Neurology and Neurosurgery “Manuel Velasco Suárez”, SS, Av. Insurgentes Sur No. 3877, Mexico City 14269, Mexico;
| | - José Pedraza-Chaverri
- Facultad de Química, Departamento de Biología, Universidad Nacional Autónoma de México, CDMX 04510, Mexico; (J.P.-C.); (O.N.M.-C.)
| | - Omar N. Medina-Campos
- Facultad de Química, Departamento de Biología, Universidad Nacional Autónoma de México, CDMX 04510, Mexico; (J.P.-C.); (O.N.M.-C.)
| | - Perla D. Maldonado
- Laboratory of Cerebral Vascular Pathology, National Institute of Neurology and Neurosurgery “Manuel Velasco Suárez”, SS, Av. Insurgentes Sur No. 3877, Mexico City 14269, Mexico;
| | - Patricia Rojas
- Laboratory of Neurotoxicology, National Institute of Neurology and Neurosurgery “Manuel Velasco Suárez”, SS, Av. Insurgentes Sur No. 3877, Mexico City 14269, Mexico;
- Correspondence: ; Tel.: +52-55-5424-0808
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Stewart A, Davis GL, Gresch PJ, Katamish RM, Peart R, Rabil MJ, Gowrishankar R, Carroll FI, Hahn MK, Blakely RD. Serotonin transporter inhibition and 5-HT 2C receptor activation drive loss of cocaine-induced locomotor activation in DAT Val559 mice. Neuropsychopharmacology 2019; 44:994-1006. [PMID: 30578419 PMCID: PMC6462012 DOI: 10.1038/s41386-018-0301-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 11/19/2018] [Accepted: 12/15/2018] [Indexed: 11/18/2022]
Abstract
Dopamine (DA) signaling dysfunction is believed to contribute to multiple neuropsychiatric disorders including attention-deficit/hyperactivity disorder (ADHD). The rare DA transporter (DAT) coding substitution Ala559Val found in subjects with ADHD, bipolar disorder and autism, promotes anomalous DA efflux in vitro and, in DAT Val559 mice, leads to increased reactivity to imminent handling, waiting impulsivity, and enhanced motivation for reward. Here, we report that, in contrast to amphetamine and methylphenidate, which induce significant locomotor activation, cocaine administration to these mice elicits no locomotor effects, despite retention of conditioned place preference (CPP). Additionally, cocaine fails to elevate extracellular DA. Given that amphetamine and methylphenidate, unlike cocaine, lack high-affinity interactions with the serotonin (5-HT) transporter (SERT), we hypothesized that the lack of cocaine-induced hyperlocomotion in DAT Val559 mice arises from SERT blockade and augmented 5-HT signaling relative to cocaine actions on wildtype animals. Consistent with this idea, the SERT blocker fluoxetine abolished methylphenidate-induced locomotor activity in DAT Val559 mice, mimicking the effects seen with cocaine. Additionally, a cocaine analog (RTI-113) with greater selectivity for DAT over SERT retains locomotor activation in DAT Val559 mice. Furthermore, genetic elimination of high-affinity cocaine interactions at SERT in DAT Val559 mice, or specific inhibition of 5-HT2C receptors in these animals, restored cocaine-induced locomotion, but did not restore cocaine-induced elevations of extracellular DA. Our findings reveal a significant serotonergic plasticity arising in the DAT Val559 model that involves enhanced 5-HT2C signaling, acting independently of striatal DA release, capable of suppressing the activity of cocaine-sensitive motor circuits.
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Affiliation(s)
- Adele Stewart
- 0000 0004 0635 0263grid.255951.fDepartment of Biomedical Science, Florida Atlantic University, Jupiter, FL USA
| | - Gwynne L. Davis
- 0000 0004 0635 0263grid.255951.fDepartment of Biomedical Science, Florida Atlantic University, Jupiter, FL USA ,0000 0001 2264 7217grid.152326.1Neuroscience Graduate Program, Vanderbilt University, Nashville, TN USA
| | - Paul J. Gresch
- 0000 0004 0635 0263grid.255951.fDepartment of Biomedical Science, Florida Atlantic University, Jupiter, FL USA ,0000 0004 0635 0263grid.255951.fBrain Institute, Florida Atlantic University, Jupiter, FL USA
| | - Rania M. Katamish
- 0000 0004 0635 0263grid.255951.fDepartment of Biomedical Science, Florida Atlantic University, Jupiter, FL USA
| | - Rodeania Peart
- 0000 0004 0635 0263grid.255951.fWilkes Honors College, Florida Atlantic University, Jupiter, FL USA
| | - Maximilian J. Rabil
- 0000 0004 0635 0263grid.255951.fDepartment of Biomedical Science, Florida Atlantic University, Jupiter, FL USA
| | - Raajaram Gowrishankar
- 0000 0004 0635 0263grid.255951.fDepartment of Biomedical Science, Florida Atlantic University, Jupiter, FL USA ,0000 0001 2264 7217grid.152326.1Neuroscience Graduate Program, Vanderbilt University, Nashville, TN USA ,0000 0001 2264 7217grid.152326.1International Scholars Program, Vanderbilt University, Nashville, TN USA
| | - F. Ivy Carroll
- 0000000100301493grid.62562.35Research Triangle Institute, Research Triangle Park, NC USA
| | - Maureen K. Hahn
- 0000 0004 0635 0263grid.255951.fDepartment of Biomedical Science, Florida Atlantic University, Jupiter, FL USA ,0000 0004 0635 0263grid.255951.fBrain Institute, Florida Atlantic University, Jupiter, FL USA
| | - Randy D. Blakely
- 0000 0004 0635 0263grid.255951.fDepartment of Biomedical Science, Florida Atlantic University, Jupiter, FL USA ,0000 0004 0635 0263grid.255951.fBrain Institute, Florida Atlantic University, Jupiter, FL USA
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Chagraoui A, Whitestone S, Baassiri L, Manem J, Di Giovanni G, De Deurwaerdère P. Neurochemical impact of the 5-HT2C receptor agonist WAY-163909 on monoamine tissue content in the rat brain. Neurochem Int 2019; 124:245-255. [DOI: 10.1016/j.neuint.2019.01.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 01/13/2019] [Accepted: 01/22/2019] [Indexed: 01/08/2023]
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Role of glutamatergic system and mesocorticolimbic circuits in alcohol dependence. Prog Neurobiol 2018; 171:32-49. [PMID: 30316901 DOI: 10.1016/j.pneurobio.2018.10.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 09/08/2018] [Accepted: 10/08/2018] [Indexed: 02/06/2023]
Abstract
Emerging evidence demonstrates that alcohol dependence is associated with dysregulation of several neurotransmitters. Alterations in dopamine, glutamate and gamma-aminobutyric acid release are linked to chronic alcohol exposure. The effects of alcohol on the glutamatergic system in the mesocorticolimbic areas have been investigated extensively. Several studies have demonstrated dysregulation in the glutamatergic systems in animal models exposed to alcohol. Alcohol exposure can lead to an increase in extracellular glutamate concentrations in mesocorticolimbic brain regions. In addition, alcohol exposure affects the expression and functions of several glutamate receptors and glutamate transporters in these brain regions. In this review, we discussed the effects of alcohol exposure on glutamate receptors, glutamate transporters and glutamate homeostasis in each area of the mesocorticolimbic system. In addition, we discussed the genetic aspect of alcohol associated with glutamate and reward circuitry. We also discussed the potential therapeutic role of glutamate receptors and glutamate transporters in each brain region for the treatment of alcohol dependence. Finally, we provided some limitations on targeting the glutamatergic system for potential therapeutic options for the treatment alcohol use disorders.
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Wild CT, Miszkiel JM, Wold EA, Soto CA, Ding C, Hartley RM, White MA, Anastasio NC, Cunningham KA, Zhou J. Design, Synthesis, and Characterization of 4-Undecylpiperidine-2-carboxamides as Positive Allosteric Modulators of the Serotonin (5-HT) 5-HT 2C Receptor. J Med Chem 2018; 62:288-305. [PMID: 29620897 DOI: 10.1021/acs.jmedchem.8b00401] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
An impaired signaling capacity of the serotonin (5-HT) 5-HT2C receptor (5-HT2CR) has been implicated in the neurobehavioral processes that promote relapse vulnerability in cocaine use disorder (CUD). Restoration of the diminished 5-HT2CR signaling through positive allosteric modulation presents a novel therapeutic approach. Several new molecules with the 4-alkylpiperidine-2-carboxamide scaffold were designed, synthesized, and pharmacologically evaluated, leading to the discovery of selective 5-HT2CR positive allosteric modulators (PAMs). Compound 16 (CYD-1-79) potentiated 5-HT-evoked intracellular calcium release in cells stably expressing the human 5-HT2CR but not the 5-HT2AR cells. A topographically distinct allosteric site was identified based on the newly solved 5-HT2CR structure. Compound 16 modulated 5-HT2CR-mediated spontaneous ambulation, partially substituted for the training dose of the 5-HT2CR agonist WAY163909, synergized with a low dose of WAY163909 to substitute fully for the stimulus effects of WAY163909, and attenuated relapse vulnerability as assessed in a rodent self-administration model, indicating its therapeutic promise for CUD.
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The central serotonin2B receptor as a new pharmacological target for the treatment of dopamine-related neuropsychiatric disorders: Rationale and current status of research. Pharmacol Ther 2018; 181:143-155. [DOI: 10.1016/j.pharmthera.2017.07.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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10
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Ge W, Li H, Zhao Y, Cai E, Zhu H, Gao Y, Liu S, Yang H, Zhang L. Study on antidepressant activity of sesquiterpenoids from ginseng root. J Funct Foods 2017. [DOI: 10.1016/j.jff.2017.03.057] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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Behavioral, pharmacological and neuroanatomical analysis of serotonin 2C receptor agonism on maternal behavior in rats. Psychoneuroendocrinology 2016; 73:252-262. [PMID: 27566488 PMCID: PMC5048576 DOI: 10.1016/j.psyneuen.2016.08.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 07/28/2016] [Accepted: 08/15/2016] [Indexed: 01/23/2023]
Abstract
As a highly motivated social behavior, maternal behavior in rats has been routinely used to study psychoactive drugs for clinical, neuroscience and pharmacological purposes. Recent evidence indicates that acute activation of serotonin 2C (5-HT2C) receptors causes a disruption of rat maternal behavior. The present study was designed to elucidate the behavioral, pharmacological mechanisms and neuroanatomical basis of this 5-HT2C effect. First, we replicated the finding that acute MK212 injection (2.0mg/kg, a highly selective 5-HT2C agonist) disrupts maternal behavior, especially on pup retrieval. Interestingly, this disruption was significantly attenuated by 4-h pup separation (a procedure putatively increased maternal motivation). MK212 also suppressed food retrieval, indicating that it has a general effect on motivated behaviors. Second, we showed that MK212 disrupts maternal behavior by specifically activating 5-HT2C receptor, as pretreatment with a 5-HT2C receptor antagonist SB242084 (0.6 and 1.0mg/kg) alleviated MK212-induced disruption on pup retrieval. Third, we microinjected MK212 into various brain regions implicated in the regulation of maternal behavior: nucleus accumbens shell (25, 75, 250ng/0.5μl/side), medial prefrontal cortex (25 and 250ng, 1, 2 and 5μg/0.5μl/side), and medial preoptic area (MPOA, 75ng, 1 and 5μg/0.5μl/side). Pup retrieval and other maternal responses were not affected by any of these manipulations. Finally, we used c-Fos immunohistochemistry to identify the central mechanisms of the acute and repeated MK212 effects on maternal behavior. Acute MK212 (2.0mg/kg) disrupted pup retrieval and concurrently decreased c-Fos expression in the ventral part of lateral septal nucleus (LSv), MPOA, dentate gyrus (DG) and dorsal raphe (DR), but increased it in the central amygdala (CeA). Five days of repeated MK212 (2.0mg/kg) treatment produced a persistent disruption of pup retrieval and only decreased c-Fos expression in the DR. These findings not only confirm a role of 5-HT2C receptor in rat maternal behavior, but also suggest that the coordinated 5-HT2C activity in various limbic (e.g., LSv, DG, CeA), hypothalamic regions (e.g., MPOA) and brainstem areas (e.g. DR), is likely involved in the mediation of important psychological processes (e.g. motor function, motivation) necessary for the normal expression of maternal behavior.
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Swinford-Jackson SE, Anastasio NC, Fox RG, Stutz SJ, Cunningham KA. Incubation of cocaine cue reactivity associates with neuroadaptations in the cortical serotonin (5-HT) 5-HT2C receptor (5-HT2CR) system. Neuroscience 2016; 324:50-61. [PMID: 26926963 DOI: 10.1016/j.neuroscience.2016.02.052] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Revised: 02/15/2016] [Accepted: 02/23/2016] [Indexed: 11/28/2022]
Abstract
Intensification of craving elicited by drug-associated cues during abstinence occurs over time in human cocaine users while elevation of cue reactivity ("incubation") is observed in rats exposed to extended forced abstinence from cocaine self-administration. Incubation in rodents has been linked to time-dependent neuronal plasticity in the medial prefrontal cortex (mPFC). We tested the hypothesis that incubation of cue reactivity during abstinence from cocaine self-administration is accompanied by lower potency and/or efficacy of the selective serotonin (5-HT) 5-HT2C receptor (5-HT2CR) agonist WAY163909 to suppress cue reactivity and a shift in the subcellular localization profile of the mPFC 5-HT2CR protein. We observed incubation of cue reactivity (measured as lever presses reinforced by the discrete cue complex) between Day 1 and Day 30 of forced abstinence from cocaine relative to sucrose self-administration. Pharmacological and biochemical analyses revealed that the potency of the selective 5-HT2CR agonist WAY163909 to suppress cue reactivity, the expression of synaptosomal 5-HT2CR protein in the mPFC, and the membrane to cytoplasmic expression of the 5-HT2CR in mPFC were lower on Day 30 vs. Day 1 of forced abstinence from cocaine self-administration. Incubation of cue reactivity assessed during forced abstinence from sucrose self-administration did not associate with 5-HT2CR protein expression in the mPFC. Collectively, these outcomes are the first indication that neuroadaptations in the 5-HT2CR system may contribute to incubation of cocaine cue reactivity.
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Affiliation(s)
- S E Swinford-Jackson
- Center for Addiction Research, University of Texas Medical Branch, Galveston, TX, USA
| | - N C Anastasio
- Center for Addiction Research, University of Texas Medical Branch, Galveston, TX, USA; Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA
| | - R G Fox
- Center for Addiction Research, University of Texas Medical Branch, Galveston, TX, USA
| | - S J Stutz
- Center for Addiction Research, University of Texas Medical Branch, Galveston, TX, USA
| | - K A Cunningham
- Center for Addiction Research, University of Texas Medical Branch, Galveston, TX, USA; Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA.
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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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Central serotonin2B receptor blockade inhibits cocaine-induced hyperlocomotion independently of changes of subcortical dopamine outflow. Neuropharmacology 2015; 97:329-37. [DOI: 10.1016/j.neuropharm.2015.06.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 06/10/2015] [Accepted: 06/16/2015] [Indexed: 12/31/2022]
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15
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Higgins GA, Fletcher PJ. Therapeutic Potential of 5-HT2C Receptor Agonists for Addictive Disorders. ACS Chem Neurosci 2015; 6:1071-88. [PMID: 25870913 DOI: 10.1021/acschemneuro.5b00025] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The neurotransmitter 5-hydroxytryptamine (5-HT; serotonin) has long been associated with the control of a variety of motivated behaviors, including feeding. Much of the evidence linking 5-HT and feeding behavior was obtained from studies of the effects of the 5-HT releaser (dex)fenfluramine in laboratory animals and humans. Recently, the selective 5-HT2C receptor agonist lorcaserin received FDA approval for the treatment of obesity. This review examines evidence to support the use of selective 5-HT2C receptor agonists as treatments for conditions beyond obesity, including substance abuse (particularly nicotine, psychostimulant, and alcohol dependence), obsessive compulsive, and excessive gambling disorder. Following a brief survey of the early literature supporting a role for 5-HT in modulating food and drug reinforcement, we propose that intrinsic differences between SSRI and serotonin releasers may have underestimated the value of serotonin-based pharmacotherapeutics to treat clinical forms of addictive behavior beyond obesity. We then highlight the critical involvement of the 5-HT2C receptor in mediating the effect of (dex)fenfluramine on feeding and body weight gain and the evidence that 5-HT2C receptor agonists reduce measures of drug reward and impulsivity. A recent report of lorcaserin efficacy in a smoking cessation trial further strengthens the idea that 5-HT2C receptor agonists may have potential as a treatment for addiction. This review was prepared as a contribution to the proceedings of the 11th International Society for Serotonin Research Meeting held in Hermanus, South Africa, July 9-12, 2014.
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Affiliation(s)
- Guy A. Higgins
- InterVivo Solutions Inc., 120 Carlton Street, Toronto, ON M5A
4K2, Canada
- Department of Pharmacology & Toxicology, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Paul J. Fletcher
- Section of Biopsychology
and Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 250 College Street, Toronto, ON M5T 1R8, Canada
- Departments of Psychiatry & Psychology, University of Toronto, Toronto, ON M5T 1R8, Canada
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Nocjar C, Alex KD, Sonneborn A, Abbas AI, Roth BL, Pehek EA. Serotonin-2C and -2a receptor co-expression on cells in the rat medial prefrontal cortex. Neuroscience 2015; 297:22-37. [PMID: 25818050 PMCID: PMC4595040 DOI: 10.1016/j.neuroscience.2015.03.050] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Revised: 03/20/2015] [Accepted: 03/20/2015] [Indexed: 11/28/2022]
Abstract
Neural function within the medial prefrontal cortex (mPFC) regulates normal cognition, attention and impulse control, implicating neuroregulatory abnormalities within this region in mental dysfunction related to schizophrenia, depression and drug abuse. Both serotonin-2A (5-HT2A) and -2C (5-HT2C) receptors are known to be important in neuropsychiatric drug action and are distributed throughout the mPFC. However, their interactive role in serotonergic cortical regulation is poorly understood. While the main signal transduction mechanism for both receptors is stimulation of phosphoinositide production, they can have opposite effects downstream. 5-HT2A versus 5-HT2C receptor activation oppositely regulates behavior and can oppositely affect neurochemical release within the mPFC. These distinct receptor effects could be caused by their differential cellular distribution within the cortex and/or other areas. It is known that both receptors are located on GABAergic and pyramidal cells within the mPFC, but it is not clear whether they are expressed on the same or different cells. The present work employed immunofluorescence with confocal microscopy to examine this in layers V-VI of the prelimbic mPFC. The majority of GABA cells in the deep prelimbic mPFC expressed 5-HT2C receptor immunoreactivity. Furthermore, most cells expressing 5-HT2C receptor immunoreactivity notably co-expressed 5-HT2A receptors. However, 27% of 5-HT2C receptor immunoreactive cells were not GABAergic, indicating that a population of prelimbic pyramidal projection cells could express the 5-HT2C receptor. Indeed, some cells with 5-HT2C and 5-HT2A receptor co-labeling had a pyramidal shape and were expressed in the typical layered fashion of pyramidal cells. This indirectly demonstrates that 5-HT2C and 5-HT2A receptors may be commonly co-expressed on GABAergic cells within the deep layers of the prelimbic mPFC and perhaps co-localized on a small population of local pyramidal projection cells. Thus a complex interplay of cortical 5-HT2A and 5-HT2C receptor mechanisms exists, which if altered, could modulate efferent brain systems implicated in mental illness.
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Affiliation(s)
- C Nocjar
- Louis Stokes Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA; Department of Psychiatry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
| | - K D Alex
- Louis Stokes Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA; Department of Neurosciences, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
| | - A Sonneborn
- Louis Stokes Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA.
| | - A I Abbas
- Department of Psychiatry, Columbia University, New York, NY 10032, USA; Division of Integrative Neuroscience, New York State Psychiatric Institute, New York, NY 10032, USA.
| | - B L Roth
- Department of Pharmacology, University of North Carolina-Chapel Hill School of Medicine, 120 Mason Farm Road, 4072 Genetic Medicine Building, Campus Box 7365, Chapel Hill, NC 27599-7365, USA.
| | - E A Pehek
- Louis Stokes Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA; Department of Neurosciences, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA; Department of Psychiatry, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
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Howell LL, Cunningham KA. Serotonin 5-HT2 receptor interactions with dopamine function: implications for therapeutics in cocaine use disorder. Pharmacol Rev 2015; 67:176-97. [PMID: 25505168 DOI: 10.1124/pr.114.009514] [Citation(s) in RCA: 167] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Cocaine exhibits prominent abuse liability, and chronic abuse can result in cocaine use disorder with significant morbidity. Major advances have been made in delineating neurobiological mechanisms of cocaine abuse; however, effective medications to treat cocaine use disorder remain to be discovered. The present review will focus on the role of serotonin (5-HT; 5-hydroxytryptamine) neurotransmission in the neuropharmacology of cocaine and related abused stimulants. Extensive research suggests that the primary contribution of 5-HT to cocaine addiction is a consequence of interactions with dopamine (DA) neurotransmission. The literature on the neurobiological and behavioral effects of cocaine is well developed, so the focus of the review will be on cocaine with inferences made about other monoamine uptake inhibitors and releasers based on mechanistic considerations. 5-HT receptors are widely expressed throughout the brain, and several different 5-HT receptor subtypes have been implicated in mediating the effects of endogenous 5-HT on DA. However, the 5-HT2A and 5-HT2C receptors in particular have been implicated as likely candidates for mediating the influence of 5-HT in cocaine abuse as well as to traits (e.g., impulsivity) that contribute to the development of cocaine use disorder and relapse in humans. Lastly, new approaches are proposed to guide targeted development of serotonergic ligands for the treatment of cocaine use disorder.
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Affiliation(s)
- Leonard L Howell
- Yerkes National Primate Research Center, Emory University, Atlanta, Georgia (L.L.H.); and Center for Addiction Research and Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas (K.A.C.)
| | - Kathryn A Cunningham
- Yerkes National Primate Research Center, Emory University, Atlanta, Georgia (L.L.H.); and Center for Addiction Research and Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas (K.A.C.)
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Cathala A, Devroye C, Maitre M, Piazza PV, Abrous DN, Revest JM, Spampinato U. Serotonin2C receptors modulate dopamine transmission in the nucleus accumbens independently of dopamine release: behavioral, neurochemical and molecular studies with cocaine. Addict Biol 2015; 20:445-57. [PMID: 24661380 DOI: 10.1111/adb.12137] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
In keeping with its ability to control the mesoaccumbens dopamine (DA) pathway, the serotonin2C receptor (5-HT2C R) plays a key role in mediating the behavioral and neurochemical effects of drugs of abuse. Studies assessing the influence of 5-HT2C R agonists on cocaine-induced responses have suggested that 5-HT2C Rs can modulate mesoaccumbens DA pathway activity independently of accumbal DA release, thereby controlling DA transmission in the nucleus accumbens (NAc). In the present study, we assessed this hypothesis by studying the influence of the 5-HT2C R agonist Ro 60-0175 on cocaine-induced behavioral, neurochemical and molecular responses. The i.p. administration of 1 mg/kg Ro 60-0175 inhibited hyperlocomotion induced by cocaine (15 mg/kg, i.p.), had no effect on cocaine-induced DA outflow in the shell, and increased it in the core subregion of the NAc. Furthermore, Ro 60-0175 inhibited the late-onset locomotion induced by the subcutaneous administration of the DA-D2 R agonist quinpirole (0.5 mg/kg), as well as cocaine-induced increase in c-Fos immunoreactivity in NAc subregions. Finally, Ro 60-0175 inhibited cocaine-induced phosphorylation of the DA and c-AMP regulated phosphoprotein of Mr 32 kDa (DARPP-32) at threonine residues in the NAc core, this effect being reversed by the selective 5-HT2C R antagonist SB 242084 (0.5 mg/kg, i.p.). Altogether, these findings demonstrate that 5-HT2C Rs are capable of modulating mesoaccumbens DA pathway activity at post-synaptic level by specifically controlling DA signaling in the NAc core subregion. In keeping with the tight relationship between locomotor activity and NAc DA function, this interaction could participate in the inhibitory control of cocaine-induced locomotor activity.
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Affiliation(s)
- Adeline Cathala
- Neurocentre Magendie, Physiopathology of Addiction Group; Inserm U862; France
- Université de Bordeaux; France
| | - Céline Devroye
- Neurocentre Magendie, Physiopathology of Addiction Group; Inserm U862; France
- Université de Bordeaux; France
| | - Marlène Maitre
- Neurocentre Magendie, Physiopathology of Addiction Group; Inserm U862; France
- Université de Bordeaux; France
| | - Pier Vincenzo Piazza
- Neurocentre Magendie, Physiopathology of Addiction Group; Inserm U862; France
- Université de Bordeaux; France
| | - Djoher Nora Abrous
- Neurocentre Magendie, Physiopathology of Addiction Group; Inserm U862; France
- Neurocentre Magendie, Neurogenesis and Pathophysiology Group; Inserm U862; France
| | - Jean-Michel Revest
- Neurocentre Magendie, Physiopathology of Addiction Group; Inserm U862; France
- Université de Bordeaux; France
| | - Umberto Spampinato
- Neurocentre Magendie, Physiopathology of Addiction Group; Inserm U862; France
- Université de Bordeaux; France
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Bezzina G, Body S, Cheung THC, Hampson CL, Bradshaw CM, Glennon JC, Szabadi E. Evidence for a role of 5-HT2C receptors in the motor aspects of performance, but not the efficacy of food reinforcers, in a progressive ratio schedule. Psychopharmacology (Berl) 2015; 232:699-711. [PMID: 25134499 DOI: 10.1007/s00213-014-3700-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Accepted: 07/28/2014] [Indexed: 12/25/2022]
Abstract
RATIONALE 5-Hydroxytryptamine2C (5-HT2C) receptor agonists reduce the breakpoint in progressive ratio schedules of reinforcement, an effect that has been attributed to a decrease of the efficacy of positive reinforcers. However, a reduction of the breakpoint may also reflect motor impairment. Mathematical models can help to differentiate between these processes. OBJECTIVE The effects of the 5-HT2C receptor agonist Ro-600175 ((αS)-6-chloro-5-fluoro-α-methyl-1H-indole-1-ethanamine) and the non-selective 5-HT receptor agonist 1-(m-chlorophenyl)piperazine (mCPP) on rats' performance on a progressive ratio schedule maintained by food pellet reinforcers were assessed using a model derived from Killeen's Behav Brain Sci 17:105-172, 1994 general theory of schedule-controlled behaviour, 'mathematical principles of reinforcement'. METHOD Rats were trained under the progressive ratio schedule, and running and overall response rates in successive ratios were analysed using the model. The effects of the agonists on estimates of the model's parameters, and the sensitivity of these effects to selective antagonists, were examined. RESULTS Ro-600175 and mCPP reduced the breakpoint. Neither agonist significantly affected a (the parameter expressing incentive value), but both agonists increased δ (the parameter expressing minimum response time). The effects of both agonists could be attenuated by the selective 5-HT2C receptor antagonist SB-242084 (6-chloro-5-methyl-N-{6-[(2-methylpyridin-3-yl)oxy]pyridin-3-yl}indoline-1-carboxamide). The effect of mCPP was not altered by isamoltane, a selective 5-HT1B receptor antagonist, or MDL-100907 ((±)2,3-dimethoxyphenyl-1-(2-(4-piperidine)methanol)), a selective 5-HT2A receptor antagonist. CONCLUSIONS The results are consistent with the hypothesis that the effect of the 5-HT2C receptor agonists on progressive ratio schedule performance is mediated by an impairment of motor capacity rather than by a reduction of the incentive value of the food reinforcer.
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Affiliation(s)
- G Bezzina
- Psychopharmacology Section, Division of Psychiatry, University of Nottingham, Medical School, Nottingham, NG7 2UH, UK
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Effect of a selective cyclooxygenase type 2 inhibitor celecoxib on depression associated with obesity in mice: an approach using behavioral tests. Neurochem Res 2014; 39:1395-402. [PMID: 24816895 DOI: 10.1007/s11064-014-1322-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 04/19/2014] [Accepted: 04/30/2014] [Indexed: 10/25/2022]
Abstract
The biological mechanisms that link the development of depression to metabolic disorders such as obesity and diabetes remain ambiguous. In the present study the potential of a selective cyclooxygenase inhibitor celecoxib (15 mg/kg p.o.) was investigated in depression associated with obesity in mice. Behavioral tests used to assess depressive-like behavior were sucrose preference test, forced swim test (FST), tail suspension test (TST) and elevated plus maze (EPM). The basal locomotor score in obese mice was not altered. Furthermore, estimation of biochemical parameters was performed for plasma glucose, total cholesterol, triglycerides and total proteins. Escitalopram (10 mg/kg p.o.) served as reference standard drug. In the results, chronic treatment with celecoxib for 28 days significantly attenuated the behavioral alterations as indicated by increased the sucrose consumption, reduced the immobility time in FST and TST, increased the percent open arm time and entries in EPM in obese mice. In the biochemical parameters celecoxib significantly reversed the increased plasma glucose, total cholesterol, triglycerides and total proteins in obese mice. In conclusion, celecoxib exhibited potential antidepressant-like effect in depression associated with obesity, which to some extent is mediated by reversing the altered plasma glucose in obese mice.
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21
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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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22
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The role of serotonin in memory: interactions with neurotransmitters and downstream signaling. Exp Brain Res 2014; 232:723-38. [PMID: 24430027 DOI: 10.1007/s00221-013-3818-4] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Accepted: 12/20/2013] [Indexed: 12/14/2022]
Abstract
Serotonin, or 5-hydroxytryptamine (5-HT), is found to be involved in many physiological or pathophysiological processes including cognitive function. Seven distinct receptors (5-HT1-7), each with several subpopulations, have been identified for serotonin, which are different in terms of localization and downstream signaling. Because of the development of selective agonists and antagonists for these receptors as well as transgenic animal models of cognitive disorders, our understanding of the role of serotonergic transmission in learning and memory has improved in recent years. A large body of evidence indicates the interplay between serotonergic transmission and other neurotransmitters including acetylcholine, dopamine, γ-aminobutyric acid (GABA) and glutamate, in the neurobiological control of learning and memory. In addition, there has been an alteration in the density of serotonergic receptors in aging and Alzheimer's disease, and serotonin modulators are found to alter the process of amyloidogenesis and exert cognitive-enhancing properties. Here, we discuss the serotonin-induced modulation of various systems involved in mnesic function including cholinergic, dopaminergic, GABAergic, glutamatergic transmissions as well as amyloidogenesis and intracellular pathways.
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23
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Liu X, Liu F, Yue R, Li Y, Zhang J, Wang S, Zhang S, Wang R, Shan L, Zhang W. The antidepressant-like effect of bacopaside I: possible involvement of the oxidative stress system and the noradrenergic system. Pharmacol Biochem Behav 2013; 110:224-30. [PMID: 23872136 DOI: 10.1016/j.pbb.2013.07.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2013] [Revised: 06/29/2013] [Accepted: 07/07/2013] [Indexed: 11/25/2022]
Abstract
In the present study, the antidepressant-like effect of bacopaside I, a saponin compound present in the Bacopa monniera plant, was evaluated by behavioral and neurochemical methods. Bacopaside I (50, 15 and 5 mg/kg) was given to mice via oral gavage for 7 successive days. The treatment significantly decreased the immobility time in mouse models of despair tests, but it did not influence locomotor activity. Neurochemical assays suggested that treatment by bacopaside I (50, 15 and 5 mg/kg) improved brain antioxidant activity to varying degrees after the behavioral despair test. Bacopaside I (15 and 5 mg/kg) significantly reversed reserpine-induced depressive-like behaviors, including low temperature and ptosis. Conversely, bacopaside I did not affect either brain MAO-A or MAO-B activity after the behavioral despair test in mice. Additionally, 5-hydroxytryptophan (a precursor of 5-serotonin) was not involved in the antidepressant-like effect of bacopaside I. These findings indicated that the antidepressant-like effect of bacopaside I might be related to both antioxidant activation and noradrenergic activation, although the exact mechanism remains to be further elucidated.
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Affiliation(s)
- Xiaojun Liu
- School of Pharmacy, Second Military Medical University, Shanghai 200433, PR China
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24
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Serotonin2C receptors and drug addiction: focus on cocaine. Exp Brain Res 2013; 230:537-45. [PMID: 23748692 DOI: 10.1007/s00221-013-3593-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 05/22/2013] [Indexed: 12/20/2022]
Abstract
This review provides an overview of the role of central serotonin2C (5-HT2C) receptors in drug addiction, specifically focusing on their impact on the neurochemical and behavioral effects of cocaine, one of the most worldwide abused drug. First, we described the neurochemical and electrophysiological mechanisms underlying the interaction between 5-HT2C receptors and the mesocorticolimbic dopaminergic network, in keeping with the key role of this system in drug abuse and dependence. Thereafter, we focused on the role of 5-HT2C receptors in the effects of cocaine in various preclinical behavioral models used in drug addiction research, such as locomotor hyperactivity, locomotor sensitization, drug discrimination, and self-administration, to end with an overview of the neurochemical mechanisms underlying the interactions between 5-HT2C receptors, mesocorticolimbic dopamine system, and cocaine. On their whole, the presented data provide compelling preclinical evidence that 5-HT2C receptor agonists may have efficacy in the treatment of cocaine abuse and dependence, thereby underlying the need for additional clinical studies to ascertain whether preclinical data translate to the human.
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25
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Multiple controls exerted by 5-HT2C receptors upon basal ganglia function: from physiology to pathophysiology. Exp Brain Res 2013; 230:477-511. [PMID: 23615975 DOI: 10.1007/s00221-013-3508-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 03/28/2013] [Indexed: 10/26/2022]
Abstract
Serotonin2C (5-HT2C) receptors are expressed in the basal ganglia, a group of subcortical structures involved in the control of motor behaviour, mood and cognition. These receptors are mediating the effects of 5-HT throughout different brain areas via projections originating from midbrain raphe nuclei. A growing interest has been focusing on the function of 5-HT2C receptors in the basal ganglia because they may be involved in various diseases of basal ganglia function notably those associated with chronic impairment of dopaminergic transmission. 5-HT2C receptors act on numerous types of neurons in the basal ganglia, including dopaminergic, GABAergic, glutamatergic or cholinergic cells. Perhaps inherent to their peculiar molecular properties, the modality of controls exerted by 5-HT2C receptors over these cell populations can be phasic, tonic (dependent on the 5-HT tone) or constitutive (a spontaneous activity without the presence of the ligand). These controls are functionally organized in the basal ganglia: they are mainly localized in the input structures and preferentially distributed in the limbic/associative territories of the basal ganglia. The nature of these controls is modified in neuropsychiatric conditions such as Parkinson's disease, tardive dyskinesia or addiction. Most of the available data indicate that the function of 5-HT2C receptor is enhanced in cases of chronic alterations of dopamine neurotransmission. The review illustrates that 5-HT2C receptors play a role in maintaining continuous controls over the basal ganglia via multiple diverse actions. We will discuss their interest for treatments aimed at ameliorating current pharmacotherapies in schizophrenia, Parkinson's disease or drugs abuse.
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26
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Akubuiro A, Bridget Zimmerman M, Boles Ponto LL, Walsh SA, Sunderland J, McCormick L, Singh M. Hyperactive hypothalamus, motivated and non-distractible chronic overeating in ADAR2 transgenic mice. GENES BRAIN AND BEHAVIOR 2013; 12:311-22. [PMID: 23323881 DOI: 10.1111/gbb.12020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 09/16/2012] [Accepted: 01/07/2013] [Indexed: 11/29/2022]
Abstract
ADAR2 transgenic mice misexpressing the RNA editing enzyme ADAR2 (Adenosine Deaminase that act on RNA) show characteristics of overeating and experience adult onset obesity. Behavioral patterns and brain changes related to a possible addictive overeating in these transgenic mice were explored as transgenic mice display chronic hyperphagia. ADAR2 transgenic mice were assessed in their food preference and motivation to overeat in a competing reward environment with ad lib access to a running wheel and food. Metabolic activity of brain and peripheral tissue were assessed with [(18) F] fluorodeoxyglucose positron emission tomography (FDG-PET) and RNA expression of feeding related genes, ADAR2, dopamine and opiate receptors from the hypothalamus and striatum were examined. The results indicate that ADAR2 transgenic mice exhibit, (1) a food preference for diets with higher fat content, (2) significantly increased food intake that is non-distractible in a competing reward environment, (3) significantly increased messenger RNA (mRNA) expressions of ADAR2, serotonin 2C receptor (5HT2C R), D1, D2 and mu opioid receptors and no change in corticotropin-releasing hormone mRNAs and significantly reduced ADAR2 protein expression in the hypothalamus, (4) significantly increased D1 receptor and altered bioamines with no change in ADAR2, mu opioid and D2 receptor mRNA expression in the striatum and (5) significantly greater glucose metabolism in the hypothalamus, brain stem, right hippocampus, left and right mid brain regions and suprascapular peripheral tissue than controls. These results suggest that highly motivated and goal-oriented overeating behaviors of ADAR2 transgenic mice are associated with altered feeding, reward-related mRNAs and hyperactive brain mesolimbic region.
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Affiliation(s)
- A Akubuiro
- Department of Neuroscience, University of Iowa, Iowa City, IA, USA
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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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The 5-HT6 serotonin receptor antagonist SB-271046 attenuates the development and expression of nicotine-induced locomotor sensitisation in Wistar rats. Neuropharmacology 2011; 61:451-7. [DOI: 10.1016/j.neuropharm.2011.01.045] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Revised: 01/07/2011] [Accepted: 01/26/2011] [Indexed: 11/22/2022]
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Rojas P, Serrano-García N, Medina-Campos ON, Pedraza-Chaverri J, Ogren SO, Rojas C. Antidepressant-like effect of a Ginkgo biloba extract (EGb761) in the mouse forced swimming test: role of oxidative stress. Neurochem Int 2011; 59:628-36. [PMID: 21672588 DOI: 10.1016/j.neuint.2011.05.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2011] [Accepted: 05/04/2011] [Indexed: 10/18/2022]
Abstract
EGb761 is a well-defined mixture of active compounds extracted from Ginkgo biloba leaves. This extract is used clinically due to its neuroprotective effects, exerted probably via its potent antioxidant or free radical scavenger action. Previous studies suggest that oxidative stress, via free radical production, may play an important role in depression and animal models for depression-like behavior. Preclinical studies have suggested that antioxidants may have antidepressants properties. The aim of this study was to investigate the antidepressant-like of EGb761 due to its antioxidant role against oxidative stress induced in the forced swimming test, the most widely used preclinical model for assessing antidepressant-like behavior. Male BALB/c mice were pretreated with EGb761 (10mg/kg, ip) daily for 17 days followed by the forced swimming test and spontaneous locomotor activity. Animals were sacrificed to evaluate lipid peroxidation, different antioxidant enzyme activities, serotonin and dopamine content in midbrain, hippocampus and prefrontal cortex. EGb761 significantly decreased the immobility time (39%) in the forced swimming test. This antidepressant-like effect of EGb761 was associated with a reduction in lipid peroxidation and superoxide radical production (indicated by a downregulation of Mn-superoxide dismutase activity), both of which are indicators of oxidative stress. The protective effect of EGb761 is not related to excitatory or inhibitory effects in locomotor activity, and was also associated with the modulation of serotonergic and dopaminergic neurotransmission. It is suggested that EGb761 produces an antidepressant-like effect, and that an antioxidant effect against oxidative stress may be partly responsible for its observed neuroprotective effects.
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Affiliation(s)
- Patricia Rojas
- Laboratory of Neurotoxicology, National Institute of Neurology and Neurosurgery, Manuel Velasco Suárez, SS, Av. Insurgentes Sur. No. 3877, C.P. 14269, Mexico D.F., Mexico.
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Zayara AE, McIver G, Valdivia PN, Lominac KD, McCreary AC, Szumlinski KK. Blockade of nucleus accumbens 5-HT2A and 5-HT2C receptors prevents the expression of cocaine-induced behavioral and neurochemical sensitization in rats. Psychopharmacology (Berl) 2011; 213:321-35. [PMID: 20814782 PMCID: PMC3032203 DOI: 10.1007/s00213-010-1996-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Accepted: 06/08/2010] [Indexed: 11/25/2022]
Abstract
RATIONALE The serotonin 5-HT(2A) and 5-HT(2C) receptors regulate the capacity of acute cocaine to augment behavior and monoamine levels within the nucleus accumbens (NAC), a brain region involved in cocaine's addictive and psychotogenic properties. OBJECTIVES In the present study, we tested the hypothesis that NAC 5-HT(2A) and 5-HT(2C) receptor activation is involved in the expression of cocaine-induced neuroplasticity following protracted withdrawal from a sensitizing repeated cocaine regimen (days 1 and 7, 15 mg/kg; days 2-6, 30 mg/kg, i.p.). METHODS The effects of intra-NAC infusions of the 5-HT(2A) antagonist R-(+)-α-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenylethyl)]-4-piperidine methanol (MDL 100907; 0, 50, 100, 500 nM) or the 5-HT(2C) antagonist [6-chloro-5-methyl-1-(6-(2-methylpiridin-3-yloxy)pyridine-3-yl carbamoyl] inodoline dihydrochloride (SB 242084; 0, 50, 100, 500 nM) were first assessed upon the expression of locomotor activity elicited by a 15-mg/kg cocaine challenge injection administered at 3-week withdrawal. A follow-up in vivo microdialysis experiment then compared the effects of the local perfusion of 0, 50, or 100 nM of each antagonist upon cocaine-induced dopamine and glutamate sensitization in the NAC. RESULTS Although neither MDL 100907 nor SB 242084 altered acute cocaine-induced locomotion, SB 242084 reduced acute cocaine-elevated NAC dopamine and glutamate levels. Intra-NAC perfusion with either compound blocked the expression of cocaine-induced locomotor and glutamate sensitization, but only MDL 100907 pretreatment prevented the expression of cocaine-induced dopamine sensitization. CONCLUSIONS These data provide the first evidence that NAC 5-HT(2A) and 5-HT(2C) receptors are critical for the expression of cocaine-induced neuroplasticity following protracted withdrawal, which has relevance for their therapeutic utility in the treatment of addiction.
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MESH Headings
- Aminopyridines/administration & dosage
- Aminopyridines/pharmacology
- Animals
- Behavior, Animal/drug effects
- Cocaine/administration & dosage
- Cocaine/pharmacology
- Dopamine/metabolism
- Dose-Response Relationship, Drug
- Fluorobenzenes/administration & dosage
- Fluorobenzenes/pharmacology
- Glutamic Acid/metabolism
- Indoles/administration & dosage
- Indoles/pharmacology
- Male
- Microdialysis
- Neuronal Plasticity/drug effects
- Nucleus Accumbens/drug effects
- Nucleus Accumbens/metabolism
- Piperidines/administration & dosage
- Piperidines/pharmacology
- Rats
- Rats, Sprague-Dawley
- Receptor, Serotonin, 5-HT2A/drug effects
- Receptor, Serotonin, 5-HT2A/metabolism
- Receptor, Serotonin, 5-HT2C/drug effects
- Receptor, Serotonin, 5-HT2C/metabolism
- Serotonin 5-HT2 Receptor Antagonists/administration & dosage
- Serotonin 5-HT2 Receptor Antagonists/pharmacology
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Affiliation(s)
- Avi E. Zayara
- Department of Psychology and the Neuroscience Research Institute, University of California at Santa Barbara, Santa Barbara, CA 93106-9660 USA
| | - Gregor McIver
- Department of Psychology and the Neuroscience Research Institute, University of California at Santa Barbara, Santa Barbara, CA 93106-9660 USA
| | - Paola N. Valdivia
- Department of Psychology and the Neuroscience Research Institute, University of California at Santa Barbara, Santa Barbara, CA 93106-9660 USA
| | - Kevin D. Lominac
- Department of Psychology and the Neuroscience Research Institute, University of California at Santa Barbara, Santa Barbara, CA 93106-9660 USA
| | - Andrew C. McCreary
- Solvay Pharmaceuticals Research Laboratories, CJ van Houtenlaan 36, 1380 DA Weesp, The Netherlands
| | - Karen K. Szumlinski
- Department of Psychology and the Neuroscience Research Institute, University of California at Santa Barbara, Santa Barbara, CA 93106-9660 USA
- Department of Psychology, University of California at Santa Barbara, Santa Barbara, CA 93106-9660 USA
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Pockros LA, Pentkowski NS, Swinford SE, Neisewander JL. Blockade of 5-HT2A receptors in the medial prefrontal cortex attenuates reinstatement of cue-elicited cocaine-seeking behavior in rats. Psychopharmacology (Berl) 2011; 213:307-20. [PMID: 21079923 PMCID: PMC3072217 DOI: 10.1007/s00213-010-2071-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Accepted: 10/25/2010] [Indexed: 01/07/2023]
Abstract
RATIONALE The action of serotonin (5-HT) at the 5-HT(2A) receptor subtype is thought to be involved in cocaine-seeking behavior that is motivated by exposure to drug-associated cues and drug priming. 5-HT(2A) receptors are densely clustered in the ventromedial prefrontal cortex (vmPFC), an area that plays a role in mediating cocaine-seeking behavior. OBJECTIVES This study examined the hypothesis that M100907, a 5-HT(2A) receptor antagonist, infused directly in the vmPFC attenuates cue- and cocaine-primed reinstatement of cocaine-seeking behavior. METHODS Rats trained to self-administer cocaine (0.75 mg/kg, i.v.) paired with light and tone cues underwent extinction training during which operant responses produced no consequences. Once behavior extinguished, rats were tested for reinstatement of responding elicited by either response-contingent presentations of the cocaine-paired light/tone cues or by cocaine-priming injections (10 mg/kg, i.p.) within 1 min after pretreatment with microinfusions of M100907 (0.1, 0.3, 1.0, or 1.5 μg/0.2 μl/side) into the vmPFC. RESULTS Intra-vmPFC M100907 decreased cue-elicited reinstatement at the two highest doses (1.0 and 1.5 μg) but produced only a slight decrease in cocaine-primed reinstatement that was not dose dependent. The decrease in cue reinstatement was not likely due to impaired ability to respond since intra-vmPFC M100907 infusions had minimal effect on cocaine self-administration and no effect on cue-elicited sucrose-seeking behavior, or spontaneous or cocaine-induced locomotion. M100907 infusions into the adjacent anterior cingulate cortex had no effect on cue reinstatement. CONCLUSIONS The results suggest that the blockade of 5-HT(2A) receptors in the vmPFC selectively attenuates the incentive motivational effects of cocaine-paired cues.
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Affiliation(s)
- Lara A. Pockros
- Department of Psychology, Arizona State University, 950 S. McAllister, Tempe, AZ 85287, USA
| | - Nathan S. Pentkowski
- School of Life Sciences, Arizona State University, 427 East Tyler Mall, Tempe, AZ 85287, USA
| | - Sarah E. Swinford
- Department of Psychology, Arizona State University, 950 S. McAllister, Tempe, AZ 85287, USA
| | - Janet L. Neisewander
- School of Life Sciences, Arizona State University, 427 East Tyler Mall, Tempe, AZ 85287, USA
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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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35
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Nair SG, Navarre BM, Cifani C, Pickens CL, Bossert JM, Shaham Y. Role of dorsal medial prefrontal cortex dopamine D1-family receptors in relapse to high-fat food seeking induced by the anxiogenic drug yohimbine. Neuropsychopharmacology 2011; 36:497-510. [PMID: 20962767 PMCID: PMC3005956 DOI: 10.1038/npp.2010.181] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2010] [Revised: 08/21/2010] [Accepted: 09/07/2010] [Indexed: 11/09/2022]
Abstract
In humans, relapse to maladaptive eating habits during dieting is often provoked by stress. In rats, the anxiogenic drug yohimbine, which causes stress-like responses in both humans and nonhumans, reinstates food seeking in a relapse model. In this study, we examined the role of medial prefrontal cortex (mPFC) dopamine D1-family receptors, previously implicated in stress-induced reinstatement of drug seeking, in yohimbine-induced reinstatement of food seeking. We trained food-restricted rats to lever press for 35% high-fat pellets every other day (9-15 sessions, 3 h each); pellet delivery was accompanied by a discrete tone-light cue. We then extinguished operant responding for 10-16 days by removing the pellets. Subsequently, we examined the effect of yohimbine (2 mg/kg, i.p.) on reinstatement of food seeking and Fos (a neuronal activity marker) induction in mPFC. We then examined the effect of systemic injections of the D1-family receptor antagonist SCH23390 (10 μg/kg, s.c.) on yohimbine-induced reinstatement and Fos induction, and that of mPFC SCH23390 (0.5 and 1.0 μg/side) injections on this reinstatement. Yohimbine-induced reinstatement was associated with strong Fos induction in the dorsal mPFC and with weaker Fos induction in the ventral mPFC. Systemic SCH23390 injections blocked both yohimbine-induced reinstatement and mPFC Fos induction. Dorsal, but not ventral, mPFC injections of SCH23390 decreased yohimbine-induced reinstatement of food seeking. In addition, dorsal mPFC SCH23390 injections decreased pellet-priming-induced reinstatement, but had no effect on ongoing high-fat pellet self-administration or discrete-cue-induced reinstatement. Results indicate a critical role of dorsal mPFC dopamine D1-family receptors in stress-induced relapse to palatable food seeking, as well as relapse induced by acute re-exposure to food taste, texture, and smell.
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Affiliation(s)
- Sunila G Nair
- Behavioral Neuroscience Branch, NIDA/IRP/NIH/DHHS, Baltimore, MD, USA
| | | | - Carlo Cifani
- Behavioral Neuroscience Branch, NIDA/IRP/NIH/DHHS, Baltimore, MD, USA
| | - Charles L Pickens
- Behavioral Neuroscience Branch, NIDA/IRP/NIH/DHHS, Baltimore, MD, USA
| | | | - Yavin Shaham
- Behavioral Neuroscience Branch, NIDA/IRP/NIH/DHHS, Baltimore, MD, USA
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36
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The Constitutive Activity of 5-HT2C Receptors as an Additional Modality of Interaction of the Serotonergic System. 5-HT2C RECEPTORS IN THE PATHOPHYSIOLOGY OF CNS DISEASE 2011. [DOI: 10.1007/978-1-60761-941-3_10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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37
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Rojas P, Serrano-García N, Medina-Campos ON, Pedraza-Chaverri J, Maldonado PD, Ruiz-Sánchez E. S-Allylcysteine, a garlic compound, protects against oxidative stress in 1-methyl-4-phenylpyridinium-induced parkinsonism in mice. J Nutr Biochem 2010; 22:937-44. [PMID: 21190833 DOI: 10.1016/j.jnutbio.2010.08.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Revised: 07/01/2010] [Accepted: 08/13/2010] [Indexed: 11/16/2022]
Abstract
S-Allylcysteine (SAC), the most abundant organosulfur compound in aged garlic extract, has multifunctional activity via different mechanisms and neuroprotective effects that are exerted probably via its antioxidant or free radical scavenger action. The 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated mouse has been the most widely used model for assessing neuroprotective agents for Parkinson's disease. 1-Methyl-4-phenylpyridinium (MPP(+)) is the stable metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, and it causes nigrostriatal dopaminergic neurotoxicity. Previous studies suggest that oxidative stress, via free radical production, is involved in MPP(+)-induced neurotoxicity. Here, we report on the neuroprotective effect of SAC against oxidative stress induced by MPP(+) in the striatum of C57BL/6J mice. Mice were pretreated with SAC (125 mg/kg ip) daily for 17 days, followed by administration of MPP(+) (0.72 mg/kg icv), and were sacrificed 24 h later to evaluate lipid peroxidation, different antioxidant enzyme activities, spontaneous locomotor activity and dopamine (DA) content. MPP(+) administration resulted in a significant decrease in DA levels in the striatum. Mice receiving SAC (125 mg/kg ip) had significantly attenuated MPP(+)-induced loss of striatal DA levels (32%). The neuroprotective effect of SAC against MPP(+) neurotoxicity was associated with blocked (100% of protection) of lipid peroxidation and reduction of superoxide radical production - indicated by an up-regulation of Cu-Zn-superoxide dismutase activity - both of which are indices of oxidative stress. Behavioral analyses showed that SAC improved MPP(+)-induced impairment of locomotion (35%). These findings suggest that in mice, SAC attenuates MPP(+)-induced neurotoxicity in the striatum and that an antioxidant effect against oxidative stress may be partly responsible for its observed neuroprotective effects.
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Affiliation(s)
- Patricia Rojas
- Laboratory of Neurotoxicology, National Institute of Neurology and Neurosurgery, "Manuel Velasco Suárez," SS, Mexico City, D.F., Mexico.
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38
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Abstract
Only a subgroup of human drug users progress from initial drug taking to drug addiction. The learned associations between the effects of the drug and the environment in which it is experienced is an important aspect of the progression to continued drug taking and drug seeking. These associations can be modeled using the conditioned place preference (CPP) paradigm, although no current method of CPP analysis allows for the identification of within-group variability among subjects. In this study, we adapted a 'criterion' method of analysis to separate 'CPP expressing' from 'non-CPP expressing' rats to study more directly within-group variability in the CPP paradigm. Male Sprague-Dawley rats were conditioned with cocaine (5, 10, 20 mg/kg) or saline in an unbiased three-chamber CPP apparatus in either a single-trial or four-trial CPP procedure. A classification and regression tree analysis of time spent in the cocaine-paired chamber established a time of 324 s spent in the cocaine-paired chamber as the criterion for cocaine CPP expression. This criterion effectively discriminated control from cocaine-conditioned rats and was reliable for rats trained in both single trial and four-trial CPP procedures. The criterion method showed an enhanced ability to detect effective doses of cocaine in the single-trial CPP procedure and a blockade of CPP expression by MK 212 (0.125 mg/kg) treatment in a subgroup of rats. These data support the utility of the criterion analysis as an adjunct to traditional methods that compare group averages in CPP.
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Stimulation of medial prefrontal cortex serotonin 2C (5-HT(2C)) receptors attenuates cocaine-seeking behavior. Neuropsychopharmacology 2010; 35:2037-48. [PMID: 20520599 PMCID: PMC3055305 DOI: 10.1038/npp.2010.72] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Serotonin 2C receptor (5-HT(2C)R) agonists administered systemically attenuate both cocaine-primed and cue-elicited reinstatement of extinguished cocaine-seeking behavior. To further elucidate the function of these receptors in addiction-like processes, this study examined the effects of microinfusing the 5-HT(2C)R agonist MK212 (0, 10, 30, 100 ng/side/0.2 microl) into the medial prefrontal cortex (mPFC) on cocaine self-administration and reinstatement of extinguished cocaine-seeking behavior. Male Sprague-Dawley rats were trained to self-administer cocaine (0.75 mg/kg, i.v.) paired with light and tone cues. Once responding stabilized, rats received MK212 microinfusions before tests for maintenance of cocaine self-administration. Next, extinction training to reduce cocaine-seeking behavior, defined as responses performed without cocaine reinforcement available, occurred until low extinction baselines were achieved. Rats then received MK212 microinfusions before tests for reinstatement of extinguished cocaine-seeking behavior elicited by cocaine-priming injections (10 mg/kg, i.p.) or response-contingent presentations of the cocaine-associated cues; operant responses during cocaine-primed reinstatement tests produced no consequences. MK212 microinfusions into the prelimbic and infralimbic, but not anterior cingulate, regions of the mPFC dose-dependently attenuated both cocaine-primed and cue-elicited reinstatement of extinguished cocaine-seeking behavior, but did not reliably affect cocaine self-administration. A subsequent experiment showed that the effects of MK212 (100 ng/side/0.2 microl) on reinstatement of extinguished cocaine-seeking behavior were blocked by co-administration of the 5-HT(2C)R antagonist SB242084 (200 ng/side/0.2 microl). MK212 administered alone into the mPFC as a drug prime produced no discernable effects on cocaine-seeking behavior. These findings suggest that stimulation of 5-HT(2C)Rs in the mPFC attenuates the incentive motivational effects produced by sampling cocaine or exposure to drug-paired cues.
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Anastasio NC, Lanfranco MF, Bubar MJ, Seitz PK, Stutz SJ, McGinnis AG, Watson CS, Cunningham KA. Serotonin 5-HT2C receptor protein expression is enriched in synaptosomal and post-synaptic compartments of rat cortex. J Neurochem 2010; 113:1504-15. [PMID: 20345755 PMCID: PMC2917206 DOI: 10.1111/j.1471-4159.2010.06694.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The action of serotonin (5-HT) at the 5-HT(2C) receptor (5-HT(2C)R) in cerebral cortex is emerging as a candidate modulator of neural processes that mediate core phenotypic facets of several psychiatric and neurological disorders. However, our understanding of the neurobiology of the cortical 5-HT(2C)R protein complex is currently limited. The goal of the present study was to explore the subcellular localization of the 5-HT(2C)R in synaptosomes and the post-synaptic density, an electron-dense thickening specialized for post-synaptic signaling and neuronal plasticity. Utilizing multiples tissues (brain, peripheral tissues), protein fractions (synaptosomal, post-synaptic density), and controls (peptide neutralization, 5-HT(2C)R stably-expressing cells), we established the selectivity of two commercially available 5-HT(2C)R antibodies and employed the antibodies in western blot and immunoprecipitation studies of prefrontal cortex (PFC) and motor cortex, two regions implicated in cognitive, emotional and motor dysfunction. For the first time, we demonstrated the expression of the 5-HT(2C)R in post-synaptic density-enriched fractions from both PFC and motor cortex. Co-immunoprecipitation studies revealed the presence of post-synaptic density-95 within the 5-HT(2C)R protein complex expressed in PFC and motor cortex. Taken together, these data support the hypothesis that the 5-HT(2C)R is localized within the post-synaptic thickening of synapses and is therefore positioned to directly modulate synaptic plasticity in cortical neurons.
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Affiliation(s)
- Noelle C. Anastasio
- Center for Addiction Research, University of Texas Medical Branch, Galveston TX 77555
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston TX 77555
| | - Maria Fe Lanfranco
- Center for Addiction Research, University of Texas Medical Branch, Galveston TX 77555
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston TX 77555
| | - Marcy J. Bubar
- Center for Addiction Research, University of Texas Medical Branch, Galveston TX 77555
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston TX 77555
| | - Patricia K. Seitz
- Center for Addiction Research, University of Texas Medical Branch, Galveston TX 77555
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston TX 77555
| | - Sonja J. Stutz
- Center for Addiction Research, University of Texas Medical Branch, Galveston TX 77555
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston TX 77555
| | - Andrew G. McGinnis
- Center for Addiction Research, University of Texas Medical Branch, Galveston TX 77555
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston TX 77555
| | - Cheryl S. Watson
- Center for Addiction Research, University of Texas Medical Branch, Galveston TX 77555
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston TX 77555
| | - Kathryn A. Cunningham
- Center for Addiction Research, University of Texas Medical Branch, Galveston TX 77555
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston TX 77555
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Olaghere da Silva UB, Morabito MV, Canal CE, Airey DC, Emeson RB, Sanders-Bush E. Impact of RNA editing on functions of the serotonin 2C receptor in vivo. Front Neurosci 2010; 4:26. [PMID: 20582266 PMCID: PMC2858556 DOI: 10.3389/neuro.23.001.2010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Accepted: 01/20/2010] [Indexed: 01/07/2023] Open
Abstract
Transcripts encoding 5-HT(2C) receptors are modified posttranscriptionally by RNA editing, generating up to 24 protein isoforms. In recombinant cells, the fully edited isoform, 5-HT(2C-VGV), exhibits blunted G-protein coupling and reduced constitutive activity. The present studies examine the signal transduction properties of 5-HT(2C-VGV) receptors in brain to determine the in vivo consequences of altered editing. Using mice solely expressing the 5-HT(2C-VGV) receptor (VGV/Y), we demonstrate reduced G-protein coupling efficiency and high-affinity agonist binding of brain 5-HT(2C-VGV) receptors. However, enhanced behavioral sensitivity to a 5-HT(2C) receptor agonist was also seen in mice expressing 5-HT(2C-VGV) receptors, an unexpected finding given the blunted G-protein coupling. In addition, mice expressing 5-HT(2C-VGV) receptors had greater sensitivity to a 5-HT(2C) inverse agonist/antagonist enhancement of dopamine turnover relative to wild-type mice. These behavioral and biochemical results are most likely explained by increases in 5-HT(2C) receptor binding sites in the brains of mice solely expressing 5-HT(2C-VGV) receptors. We conclude that 5-HT(2C-VGV) receptor signaling in brain is blunted, but this deficiency is masked by a marked increase in 5-HT(2C) receptor binding site density in mice solely expressing the VGV isoform. These findings suggest that RNA editing may regulate the density of 5-HT(2C) receptor binding sites in brain. We further caution that the pattern of 5-HT(2C) receptor RNA isoforms may not reflect the pattern of protein isoforms, and hence the inferred overall function of the receptor.
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Affiliation(s)
| | - Michael V. Morabito
- Center for Molecular Neuroscience, Vanderbilt University School of MedicineNashville, TN, USA
| | - Clinton E. Canal
- Center for Molecular Neuroscience, Vanderbilt University School of MedicineNashville, TN, USA
- Department of Pharmacology, Vanderbilt University School of MedicineNashville, TN, USA
| | - David C. Airey
- Center for Molecular Neuroscience, Vanderbilt University School of MedicineNashville, TN, USA
- Department of Pharmacology, Vanderbilt University School of MedicineNashville, TN, USA
| | - Ronald B. Emeson
- Center for Molecular Neuroscience, Vanderbilt University School of MedicineNashville, TN, USA
- Department of Pharmacology, Vanderbilt University School of MedicineNashville, TN, USA
- Department of Psychiatry, Vanderbilt University School of MedicineNashville, TN, USA
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of MedicineNashville, TN, USA
| | - Elaine Sanders-Bush
- Center for Molecular Neuroscience, Vanderbilt University School of MedicineNashville, TN, USA
- Department of Pharmacology, Vanderbilt University School of MedicineNashville, TN, USA
- Department of Psychiatry, Vanderbilt University School of MedicineNashville, TN, USA
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Müller CP, Pum ME, Schumann G, Huston JP. The Role of Serotonin in Drug Addiction. HANDBOOK OF BEHAVIORAL NEUROSCIENCE 2010. [DOI: 10.1016/s1569-7339(10)70099-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Unilateral lesion of the nigrostriatal pathway decreases the response of interneurons in medial prefrontal cortex to 5-HT 2A/2C receptor stimulation in the rat. Brain Res 2009; 1312:127-37. [PMID: 19948151 DOI: 10.1016/j.brainres.2009.11.052] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Revised: 11/18/2009] [Accepted: 11/20/2009] [Indexed: 11/23/2022]
Abstract
The aim of the present study was to investigate changes in the firing rate and pattern of interneurons in the medial prefrontal cortex (mPFC), and effects of 5-HT(2A/2C) receptor agonist DOI and antagonist ritanserin, and the selective 5-HT(2C) receptor antagonist SB 242084 on the neuronal firing in rats with 6-hydroxydopamine (6-OHDA) lesions of the substantia nigra pars compacta (SNc) by extracellular recording in vivo. The lesion of the SNc decreased the firing rate of the interneurons compared to sham-lesioned rats, and firing pattern of these interneurons changed toward a more burst-firing. Administration of DOI (20-320 microg/kg, i.v.) dose-dependently increased the firing rate of all interneurons examined in sham-lesioned and the 6-OHDA-lesioned rats. The excitation was significant at doses higher than 40 microg/kg and 320 microg/kg in sham-lesioned and the 6-OHDA-lesioned rats, respectively. This dose, which produced marked effect in the 6-OHDA-lesioned rats, was much higher than that of sham-lesioned rats. The local application of DOI (5 microg) in mPFC increased the firing rate of the interneurons in sham-lesioned rats, while having no effect on the firing rate in the 6-OHDA-lesioned rats. The excitatory effect of DOI in sham-lesioned and the 6-OHDA-lesioned rats was completely or partially reversed by ritanserin or SB 242084. The results of our study show that lesion of the SNc leads to a decrease in the firing rate of interneurons in mPFC and fire with a more burst pattern, and decreased response of the interneurons to DOI in rat.
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Blockade of D1 dopamine receptors in the medial prefrontal cortex attenuates amphetamine- and methamphetamine-induced locomotor activity in the rat. Brain Res 2009; 1300:51-7. [PMID: 19733155 DOI: 10.1016/j.brainres.2009.08.084] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 08/19/2009] [Accepted: 08/22/2009] [Indexed: 11/22/2022]
Abstract
The medial prefrontal cortex (mPFC) is a component of the mesolimbic dopamine (DA) system involved in psychostimulant-induced hyperactivity and previous studies have shown that altering DA transmission or D2 receptors within the mPFC can decrease this stimulant effect. The goal of this study was to investigate a potential modulatory role for D1 receptors in the mPFC in amphetamine (AMPH)- and methamphetamine (METH)-induced hyperactivity. Locomotor activity in an open-field arena was measured in male, Sprague-Dawley rats given an intra-mPFC infusion of vehicle or the D1 receptor antagonist SCH 23390 (0.25 or 1.0 microg) prior to systemic (i.p.) injection of saline, AMPH (1 mg/kg), or METH (1 mg/kg). We found that SCH 23390 produced a dose-dependent decrease in AMPH- and METH-induced locomotion and rearing but had no significant effect on spontaneous behavior that occurred following systemic saline injections. Because SCH 23390 has been shown to have agonist-like properties at 5-HT(2C) receptors, a follow-up experiment was performed to determine if this contributed to the attenuation of METH-induced activity that we observed. Rats were given intra-mPFC infusions of both SCH 23390 (1.0 microg) and the 5-HT(2C) antagonist RS 102221 (0.25 microg) prior to METH (1 mg/kg, i.p.). The addition of the 5-HT(2C) antagonist failed to alter SCH 23390-induced decreases in METH-induced locomotion and rearing; infusion of RS 102221 alone had no significant effects on locomotion and produced a non-significant decrease in rearing. The results of these studies suggest that D1 activation in the mPFC plays a significant role in AMPH- and METH-induced hyperactivity.
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Editing of serotonin 2C receptor mRNA in the prefrontal cortex characterizes high-novelty locomotor response behavioral trait. Neuropsychopharmacology 2009; 34:2237-51. [PMID: 19494808 PMCID: PMC2735076 DOI: 10.1038/npp.2009.51] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Serotonin 2C receptor (5-HT(2C)R) exerts a major inhibitory influence on dopamine (DA) neurotransmission within the mesocorticolimbic DA pathway that is implicated in drug reward and goal-directed behaviors. 5-HT(2C)R pre-mRNA undergoes adenosine-to-inosine editing, generating numerous receptor isoforms in brain. As editing influences 5-HT(2C)R activity, individual differences in editing might influence dopaminergic function and, thereby, contribute to interindividual vulnerability to drug addiction. Liability to drug-related behaviors in rats can be predicted by their level of motor activity in response to a novel environment. Rats with a high locomotor response (high responders; HRs) exhibit enhanced acquisition and maintenance of drug self-administration compared to rats with a low response (low responders; LRs). We here examined 5-HT(2C)R mRNA editing and expression in HR and LR phenotypes to investigate the relationship between 5-HT(2C)R function and behavioral traits relevant to drug addiction vulnerability. Three regions of the mesocorticolimbic circuitry (ventral tegmental area (VTA), nucleus accumbens (NuAc) shell, and medial prefrontal cortex (PFC)) were examined. 5-HT(2C)R mRNA expression and editing were significantly higher in the NuAc shell compared with both the PFC and VTA, implying significant differences in function (including constitutive activity) among 5-HT(2C)R neuronal populations within the circuitry. The regional differences in editing could, at least in part, arise from the variations in expression levels of the editing enzyme, ADAR2, and/or from the variations in the ADAR2/ADAR1 ratio observed in the study. No differences in the 5-HT(2C)R expression were detected between the behavioral phenotypes. However, editing was higher in the PFC of HRs vs LRs, implicating this region in the pathophysiology of drug abuse liability.
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Bossert JM, Wihbey KA, Pickens CL, Nair SG, Shaham Y. Role of dopamine D(1)-family receptors in dorsolateral striatum in context-induced reinstatement of heroin seeking in rats. Psychopharmacology (Berl) 2009; 206:51-60. [PMID: 19506837 PMCID: PMC3145155 DOI: 10.1007/s00213-009-1580-x] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Accepted: 05/23/2009] [Indexed: 10/20/2022]
Abstract
RATIONALE In humans, exposure to environmental contexts previously associated with heroin intake can provoke relapse to drug use. In rats, exposure to heroin-associated contexts after extinction of drug-reinforced responding in different contexts reinstates heroin seeking. This effect is attenuated by blockade of D(1)-family receptors in lateral or medial accumbens shell, but not accumbens core. OBJECTIVES In this study, we further characterized the role of striatal D(1)-family receptors in context-induced reinstatement by assessing the effect of dorsolateral or dorsomedial injections of the D(1)-family receptor antagonist SCH 23390 on this reinstatement. MATERIALS AND METHODS Rats were trained to self-administer heroin (0.05-0.10 mg/kg per infusion) for 12 days; drug infusions were paired with a discrete tone-light cue. Subsequently, heroin-reinforced lever pressing was extinguished in the presence of the discrete cue in a nondrug context. During reinstatement tests under extinction conditions, the D(1)-family receptor antagonist SCH 23390 (0.3-1.0 microg per side) was injected into the dorsolateral or dorsomedial striatum prior to exposure to heroin self-administration context or the nondrug (extinction) context. We then used a disconnection procedure to examine whether D(1)-family receptors in the dorsolateral striatum and lateral accumbens shell jointly or independently support context-induced reinstatement. RESULTS Dorsolateral but not dorsomedial SCH 23390 injections attenuated context-induced reinstatement of heroin seeking. SCH 23390 injections into the dorsolateral striatum of one hemisphere and lateral accumbens shell of the other hemisphere were ineffective. CONCLUSIONS Results indicate that dorsolateral striatum D(1)-family dopamine receptors are critical for context-induced reinstatement of heroin seeking. Results also suggest that D(1)-receptor-mediated dopamine transmission in the dorsolateral striatum and lateral accumbens shell independently support this reinstatement.
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Leggio GM, Cathala A, Neny M, Rouge-Pont F, Drago F, Piazza PV, Spampinato U. In vivo evidence that constitutive activity of serotonin2C receptors in the medial prefrontal cortex participates in the control of dopamine release in the rat nucleus accumbens: differential effects of inverse agonist versus antagonist. J Neurochem 2009; 111:614-23. [PMID: 19702657 DOI: 10.1111/j.1471-4159.2009.06356.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Control of the mesoaccumbens dopamine (DA) pathway by central serotonin(2C) receptors (5-HT(2C)Rs) involves different 5-HT(2C)R populations located within multiple brain areas. Here, using in vivo microdialysis in halothane-anesthetized rats, we assessed the role of medial prefrontal cortex (mPFC) 5-HT(2C)Rs in the control of basal and activated accumbal DA outflow, to identify the modalities of their recruitment and the role of 5-HT(2C)R constitutive activity. Intra-mPFC injection of the 5-HT(2C)R inverse agonist SB 206553 (0.5 microg/0.2 microL), without effect by itself, decreased accumbal DA outflow induced by morphine (2.5-10 mg/kg, s.c.), haloperidol (0.01 mg/kg, s.c.) or GBR 12909 (2.5 mg/kg, i.p.). Conversely, intra-mPFC injection of the 5-HT(2C)R antagonist SB 242084 (0.5 microg/0.2 microL), without effect by itself, decreased the effect of 10 mg/kg morphine, the only drug enhancing basal 5-HT outflow in the mPFC. The inhibitory effect of SB 206553 on 2.5 mg/kg morphine-stimulated DA outflow was suppressed by the concomitant intra-mPFC injection of SB 242084. Finally, changes of basal DA outflow induced by the 5-HT(2C)R agonist Ro 60-0175 (3 mg/kg, i.p.) or SB 206553 (5 mg/kg, i.p.) were unaffected by intra-mPFC injection of SB 242084. These results, showing that 5-HT(2C)R antagonist and inverse agonist behave differently in vivo, demonstrate that mPFC 5-HT(2C)Rs facilitate activated accumbal DA outflow and that 5-HT(2C)R constitutive activity participates in this interaction.
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Affiliation(s)
- Gian Marco Leggio
- Inserm U862, Neurocentre Magendie, Physiopathology of Addiction group, Bordeaux F-33000, France
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Moeller FG, Schmitz JM, Steinberg JL, Green CM, Reist C, Lai LY, Swann AC, Grabowski J. Citalopram Combined with Behavioral Therapy Reduces Cocaine Use: A Double-Blind, Placebo-Controlled Trial. THE AMERICAN JOURNAL OF DRUG AND ALCOHOL ABUSE 2009; 33:367-78. [PMID: 17613964 DOI: 10.1080/00952990701313686] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Cocaine dependence continues to be a significant problem in the United States, without any approved pharmacotherapy. Promising findings from preclinical research on the effects of cocaine on serotonin lead to examination of selective serotonin reuptake inhibitors (SSRIs) as potential treatments for cocaine dependence with mixed results, possibly due to drug interactions or specifics of concomitant behavioral therapy. The purpose of this study was to examine whether the SSRI citalopram would reduce cocaine positive urines in a 12-week, double-blind placebo-controlled trial. Seventy-six cocaine dependent patients received either citalopram 20 mg per day or placebo along with cognitive behavioral therapy (CBT) and contingency management (CM). Citalopram treated subjects showed a significant reduction in cocaine-positive urines during treatment compared to placebo treated subjects. No differences were noted in retention between the two groups. Side effects reported for citalopram were mild, with none leading to discontinuation of study drug. Results of this study support further examination of citalopram in combination with behavioral therapy as a treatment for cocaine dependence.
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Affiliation(s)
- F Gerard Moeller
- Department of Psychiatry and Behavioral Science, University of Texas Health Science Center at Houston, Houston, Texas 77030, USA.
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Winter JC. Hallucinogens as discriminative stimuli in animals: LSD, phenethylamines, and tryptamines. Psychopharmacology (Berl) 2009; 203:251-63. [PMID: 18979087 DOI: 10.1007/s00213-008-1356-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Accepted: 09/24/2008] [Indexed: 12/24/2022]
Abstract
BACKGROUND Although man's first encounters with hallucinogens predate written history, it was not until the rise of the sister disciplines of organic chemistry and pharmacology in the nineteenth century that scientific studies became possible. Mescaline was the first to be isolated and its chemical structure determined. Since then, additional drugs have been recovered from their natural sources and synthetic chemists have contributed many more. Given their profound effects upon human behavior and the need for verbal communication to access many of these effects, some see humans as ideal subjects for study of hallucinogens. However, if we are to determine the mechanisms of action of these agents, establish hypotheses testable in human subjects, and explore the mechanistic links between hallucinogens and such apparently disparate topics as idiopathic psychosis, transcendental states, drug abuse, stress disorders, and cognitive dysfunction, studies in animals are essential. Stimulus control by hallucinogens has provided an intuitively attractive approach to the study of these agents in nonverbal species. OBJECTIVE The intent of this review is to provide a brief account of events from the time of the first demonstration of hallucinogen-induced stimulus control to the present. In general, the review is limited to lysergic acid diethylamide (LSD) and the hallucinogenic derivatives of phenethylamine and tryptamine. RESULTS The pharmacological basis for stimulus control by LSD and hallucinogenic phenethylamines and tryptamines is serotonergic in nature. The 5-HT(2A) receptor appears to be the primary site of action with significant modulation by other serotonergic sites including 5-HT(2C) and 5-HT(1A) receptors. Interactions with other neurotransmitters, especially glutamate and dopamine, are under active investigation. Most studies to date have been conducted in the rat but transgenic mice offer interesting possibilities. CONCLUSIONS Hallucinogen-induced stimulus control provides a unique behavioral tool for the prediction of subjective effects in man and for the elucidation of the pharmacological mechanisms of the action of these agents.
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Affiliation(s)
- J C Winter
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, 102 Farber Hall, Buffalo, NY 14214-3000, USA.
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Hayes DJ, Mosher TM, Greenshaw AJ. Differential effects of 5-HT2C receptor activation by WAY 161503 on nicotine-induced place conditioning and locomotor activity in rats. Behav Brain Res 2009; 197:323-30. [DOI: 10.1016/j.bbr.2008.08.034] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2008] [Revised: 08/21/2008] [Accepted: 08/26/2008] [Indexed: 10/21/2022]
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