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Fisher PM, Hariri AR. Linking variability in brain chemistry and circuit function through multimodal human neuroimaging. GENES BRAIN AND BEHAVIOR 2012; 11:633-42. [PMID: 22443230 DOI: 10.1111/j.1601-183x.2012.00786.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Identifying neurobiological mechanisms mediating the emergence of individual differences in behavior is critical for advancing our understanding of relative risk for psychopathology. Neuroreceptor positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) can be used to assay in vivo regional brain chemistry and function, respectively. Typically, these neuroimaging modalities are implemented independently despite the capacity for integrated data sets to offer unique insight into molecular mechanisms associated with brain function. Through examples from the serotonin and dopamine system and its effects on threat- and reward-related brain function, we review evidence for how such a multimodal neuroimaging strategy can be successfully implemented. Furthermore, we discuss how multimodal PET-fMRI can be integrated with techniques such as imaging genetics, pharmacological challenge paradigms and gene-environment interaction models to more completely map biological pathways mediating individual differences in behavior and related risk for psychopathology and inform the development of novel therapeutic targets.
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Affiliation(s)
- P M Fisher
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
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202
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Effects of environmental manipulations in genetically targeted animal models of affective disorders. Neurobiol Dis 2012; 57:12-27. [PMID: 22525570 DOI: 10.1016/j.nbd.2012.04.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 04/02/2012] [Accepted: 04/06/2012] [Indexed: 12/31/2022] Open
Abstract
Mental illness is the leading cause of disability worldwide. We are only just beginning to reveal and comprehend the complex interaction that exists between the genetic makeup of an organism and the potential modifying effect of the environment in which it lives, and how this translates into mediating susceptibility to neurological and psychiatric conditions. The capacity to address this issue experimentally has been facilitated by the availability of rodent models which allow the precise manipulation of genetic and environmental factors. In this review, we discuss the valuable nature of animal models in furthering our understanding of the relationship between genetic and environmental factors in affective illnesses, such as anxiety and depressive disorders. We first highlight the behavioral impairments exhibited by genetically targeted animal models of affective disorders, and then provide a discussion of the underlying neurobiology, focusing on animal models that involve exposure to stress. This is followed by a review of recent studies that report of beneficial effects of environmental manipulations such as environmental enrichment and enhanced physical activity and discuss the likely mechanisms that mediate those benefits.
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203
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Abstract
Memories for emotionally arousing experiences are typically vivid and persistent. The recurrent, intrusive memories of traumatic events in post-traumatic stress disorder (PTSD) are an extreme example. Stress-responsive neurotransmitters released during emotional arousal are proposed to enhance the consolidation of fear memory. These transmitters may include norepinephrine and epinephrine (NE/E) because stimulating β-adrenergic receptors shortly after training can enhance memory consolidation. However, mice lacking NE/E acquire and consolidate fear memory normally. Here, we show by using pharmacologic and genetic manipulations in mice and rats that NE/E are not essential for classical fear memory consolidation because signaling by the β(2)-adrenergic receptor is redundant with signaling by dopamine at the D(5)-dopaminergic receptor. The intracellular signaling that is stimulated by these receptors to promote consolidation uses distinct G proteins to redundantly activate phospholipase C. The results support recent evidence indicating that blocking β-adrenergic receptors alone shortly after trauma may not be sufficient to prevent PTSD.
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204
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Kleiman RJ, Chapin DS, Christoffersen C, Freeman J, Fonseca KR, Geoghegan KF, Grimwood S, Guanowsky V, Hajós M, Harms JF, Helal CJ, Hoffmann WE, Kocan GP, Majchrzak MJ, McGinnis D, McLean S, Menniti FS, Nelson F, Roof R, Schmidt AW, Seymour PA, Stephenson DT, Tingley FD, Vanase-Frawley M, Verhoest PR, Schmidt CJ. Phosphodiesterase 9A regulates central cGMP and modulates responses to cholinergic and monoaminergic perturbation in vivo. J Pharmacol Exp Ther 2012; 341:396-409. [PMID: 22328573 DOI: 10.1124/jpet.111.191353] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Cyclic nucleotides are critical regulators of synaptic plasticity and participate in requisite signaling cascades implicated across multiple neurotransmitter systems. Phosphodiesterase 9A (PDE9A) is a high-affinity, cGMP-specific enzyme widely expressed in the rodent central nervous system. In the current study, we observed neuronal staining with antibodies raised against PDE9A protein in human cortex, cerebellum, and subiculum. We have also developed several potent, selective, and brain-penetrant PDE9A inhibitors and used them to probe the function of PDE9A in vivo. Administration of these compounds to animals led to dose-dependent accumulation of cGMP in brain tissue and cerebrospinal fluid, producing a range of biological effects that implied functional significance for PDE9A-regulated cGMP in dopaminergic, cholinergic, and serotonergic neurotransmission and were consistent with the widespread distribution of PDE9A. In vivo effects of PDE9A inhibition included reversal of the respective disruptions of working memory by ketamine, episodic and spatial memory by scopolamine, and auditory gating by amphetamine, as well as potentiation of risperidone-induced improvements in sensorimotor gating and reversal of the stereotypic scratching response to the hallucinogenic 5-hydroxytryptamine 2A agonist mescaline. The results suggested a role for PDE9A in the regulation of monoaminergic circuitry associated with sensory processing and memory. Thus, PDE9A activity regulates neuronal cGMP signaling downstream of multiple neurotransmitter systems, and inhibition of PDE9A may provide therapeutic benefits in psychiatric and neurodegenerative diseases promoted by the dysfunction of these diverse neurotransmitter systems.
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Affiliation(s)
- Robin J Kleiman
- SystaMedic Inc., 1084 Shennecossett Drive, Groton, CT 06340, USA.
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205
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Kargieman L, Riga MS, Artigas F, Celada P. Clozapine Reverses Phencyclidine-Induced Desynchronization of Prefrontal Cortex through a 5-HT(1A) Receptor-Dependent Mechanism. Neuropsychopharmacology 2012; 37:723-33. [PMID: 22012474 PMCID: PMC3260989 DOI: 10.1038/npp.2011.249] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The non-competitive NMDA receptor (NMDA-R) antagonist phencyclidine (PCP)-used as a pharmacological model of schizophrenia-disrupts prefrontal cortex (PFC) activity. PCP markedly increased the discharge rate of pyramidal neurons and reduced slow cortical oscillations (SCO; 0.15-4 Hz) in rat PFC. Both effects were reversed by classical (haloperidol) and atypical (clozapine) antipsychotic drugs. Here we extended these observations to mice brain and examined the potential involvement of 5-HT(2A) and 5-HT(1A) receptors (5-HT(2A)R and 5-HT(1A)R, respectively) in the reversal by clozapine of PCP actions. Clozapine shows high in vitro affinity for 5-HT(2A)R and behaves as partial agonist in vivo at 5-HT(1A)R. We used wild-type (WT) mice and 5-HT(1A)R and 5-HT(2A)R knockout mice of the same background (C57BL/6) (KO-1A and KO-2A, respectively). Local field potentials (LFPs) were recorded in the PFC of WT, KO-1A, and KO-2A mice. PCP (10 mg/kg, intraperitoneally) reduced SCO equally in WT, KO-2A, and KO-1A mice (58±4%, 42±7%, and 63±7% of pre-drug values, n=23, 13, 11, respectively; p<0.0003). Clozapine (0.5 mg/kg, intraperitoneally) significantly reversed PCP effect in WT and KO-2A mice, but not in KO-1A mice nor in WT mice pretreated with the selective 5-HT(1A)R antagonist WAY-100635.The PCP-induced disorganization of PFC activity does not appear to depend on serotonergic function. However, the lack of effect of clozapine in KO-1A mice and the prevention by WAY-100635 indicates that its therapeutic action involves 5-HT(1A)R activation without the need to block 5-HT(2A)R, as observed with clozapine-induced cortical dopamine release.
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Affiliation(s)
- Lucila Kargieman
- Department of Neurochemistry and Neuropharmacology, Institut d'Investigacions Biomèdiques de Barcelona, Consejo Superior de Investigaciones Científicas (IIBB-CSIC), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain,Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Barcelona, Spain
| | - Maurizio S Riga
- Department of Neurochemistry and Neuropharmacology, Institut d'Investigacions Biomèdiques de Barcelona, Consejo Superior de Investigaciones Científicas (IIBB-CSIC), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain,Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Barcelona, Spain,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Francesc Artigas
- Department of Neurochemistry and Neuropharmacology, Institut d'Investigacions Biomèdiques de Barcelona, Consejo Superior de Investigaciones Científicas (IIBB-CSIC), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain,Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Barcelona, Spain,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Pau Celada
- Department of Neurochemistry and Neuropharmacology, Institut d'Investigacions Biomèdiques de Barcelona, Consejo Superior de Investigaciones Científicas (IIBB-CSIC), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain,Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Barcelona, Spain,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain,Department of Neurochemistry and Neuropharmacology, Institut d'Investigacions Biomèdiques de Barcelona, Consejo Superior de Investigaciones Científicas (IIBB-CSIC), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Rosselló 161, 6th floor, Barcelona 08036, Spain, Tel: +349 3363 8314, Fax: +349 3363 8301, E-mail:
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206
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Trakhtenberg EF, Goldberg JL. The role of serotonin in axon and dendrite growth. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2012; 106:105-26. [PMID: 23211461 DOI: 10.1016/b978-0-12-407178-0.00005-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The neurotransmitter serotonin (5-hydroxytryptamine, 5-HT) plays multiple roles in the enteric, peripheral, and central nervous systems (CNS). Although its most prominent biological function is as a signal transmission messenger from pre- to postsynaptic neurons, other roles such as shaping brain development and regulating neurite growth have also been described. Here, we review the less well-studied role of 5-HT as a modulator of neurite growth. 5-HT has been shown to regulate neurite growth in multiple systems and species, including in the mammalian CNS. 5-HT predominantly appears to suppress neurite growth, but depending on the model system and 5-HT receptor subtype, in rare cases, it may promote neurite outgrowth and elongation. Failure of axon regeneration in the adult mammalian CNS is a major problem in multiple diseases, and understanding how 5-HT receptors signal opposing effects on neurite growth may lead to novel neuroregenerative therapies, by targeting either 5-HT receptors or their downstream signaling pathways.
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Affiliation(s)
- Ephraim F Trakhtenberg
- Bascom Palmer Eye Institute, Interdisciplinary Stem Cell Institute, Neuroscience Program, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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207
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Postnatal serotonin type 2 receptor blockade prevents the emergence of anxiety behavior, dysregulated stress-induced immediate early gene responses, and specific transcriptional changes that arise following early life stress. Biol Psychiatry 2011; 70:1024-32. [PMID: 21959103 PMCID: PMC3210326 DOI: 10.1016/j.biopsych.2011.08.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 07/26/2011] [Accepted: 08/11/2011] [Indexed: 12/14/2022]
Abstract
BACKGROUND Early life adverse experience contributes to an enhanced vulnerability for adult psychopathology. Recent evidence indicates that serotonin type 2 (5-HT(2)) receptor function, implicated in the pathophysiology of mood and anxiety disorders, is significantly enhanced in the maternal separation model of early life stress. We examined whether postnatal 5-HT(2) receptor blockade would prevent the consequences of maternal separation on anxiety behavior and dysregulated gene expression. METHODS Control and maternally separated litters received treatment with the 5-HT(2) receptor antagonist, ketanserin, or vehicle during postnatal life and were examined for effects on adult anxiety behavior, adult stress-induced immediate early gene expression responses, and transcriptional changes within the prefrontal cortex during postnatal life and in adulthood. RESULTS Treatment with ketanserin during postnatal life blocked the long-lasting effects of maternal separation on anxiety behavior in the open field test and the elevated plus maze. Further, the dysregulated adult stress-induced expression pattern of the immediate early gene, Arc, observed in maternally separated animals was also prevented by postnatal ketanserin treatment. Ketanserin treatment normalized the alterations in the expression of specific genes in the prefrontal cortex of maternally separated animals, including changes in serotonin type 2A receptor messenger RNA expression during postnatal life and in genes associated with G-protein signaling in adulthood. CONCLUSIONS Postnatal treatment with the 5-HT(2) receptor antagonist, ketanserin, blocked specific consequences of maternal separation, including anxiety behavior and dysregulated gene expression in the prefrontal cortex. Our results suggest that enhanced 5-HT(2) receptor function may contribute to the emergence of anxiety behavior and perturbed stress responses following early life stress.
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208
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Affiliation(s)
- Caitlin E McOmish
- The Sackler Institute for Developmental Psychobiology at Columbia University and the New York State Psychiatric Institute, 1051 Riverside Drive, New York, NY 10032, USA
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209
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Matsushita H, Matsuzaki M, Han XJ, Nishiki TI, Ohmori I, Michiue H, Matsui H, Tomizawa K. Antidepressant-like effect of sildenafil through oxytocin-dependent cyclic AMP response element-binding protein phosphorylation. Neuroscience 2011; 200:13-8. [PMID: 22088430 DOI: 10.1016/j.neuroscience.2011.11.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 10/31/2011] [Accepted: 11/01/2011] [Indexed: 01/12/2023]
Abstract
Oxytocin (OT) levels in plasma increase during sexual response and are significantly lower in patients with depression. A drug for the treatment of sexual dysfunction, sildenafil, enhances the electrically evoked release of OT from the posterior pituitary. In this study, we showed that sildenafil had an antidepressant-like effect through activation of an OT signaling pathway. Application of sildenafil reduced depression-related behavior in male mice. The antidepressant-like effect was blocked by an OT receptor (OTR) antagonist and was absent in OTR knockout (KO) mice. Sildenafil increased the phosphorylation of cAMP response element-binding protein (CREB) in the hippocampus. The OTR antagonist inhibited sildenafil-induced CREB phosphorylation and sildenafil had no effect on CREB phosphorylation in OTR KO mice. These results suggest sildenafil to have an antidepressant-like effect through the activation of OT signaling and to be a promising drug for the treatment of depression.
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Affiliation(s)
- H Matsushita
- Department of Physiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan
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210
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Narboux-Nême N, Sagné C, Doly S, Diaz SL, Martin CBP, Angenard G, Martres MP, Giros B, Hamon M, Lanfumey L, Gaspar P, Mongeau R. Severe serotonin depletion after conditional deletion of the vesicular monoamine transporter 2 gene in serotonin neurons: neural and behavioral consequences. Neuropsychopharmacology 2011; 36:2538-50. [PMID: 21814181 PMCID: PMC3194080 DOI: 10.1038/npp.2011.142] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The vesicular monoamine transporter type 2 gene (VMAT2) has a crucial role in the storage and synaptic release of all monoamines, including serotonin (5-HT). To evaluate the specific role of VMAT2 in 5-HT neurons, we produced a conditional ablation of VMAT2 under control of the serotonin transporter (slc6a4) promoter. VMAT2(sert-cre) mice showed a major (-95%) depletion of 5-HT levels in the brain with no major alterations in other monoamines. Raphe neurons contained no 5-HT immunoreactivity in VMAT2(sert-cre) mice but developed normal innervations, as assessed by both tryptophan hydroxylase 2 and 5-HT transporter labeling. Increased 5-HT(1A) autoreceptor coupling to G protein, as assessed with agonist-stimulated [(35)S]GTP-γ-S binding, was observed in the raphe area, indicating an adaptive change to reduced 5-HT transmission. Behavioral evaluation in adult VMAT2(sert-cre) mice showed an increase in escape-like reactions in response to tail suspension and anxiolytic-like response in the novelty-suppressed feeding test. In an aversive ultrasound-induced defense paradigm, VMAT2(sert-cre) mice displayed a major increase in escape-like behaviors. Wild-type-like defense phenotype could be rescued by replenishing intracellular 5-HT stores with chronic pargyline (a monoamine oxidase inhibitor) treatment. Pargyline also allowed some form of 5-HT release, although in reduced amounts, in synaptosomes from VMAT2(sert-cre) mouse brain. These findings are coherent with the notion that 5-HT has an important role in anxiety, and provide new insights into the role of endogenous 5-HT in defense behaviors.
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Affiliation(s)
- Nicolas Narboux-Nême
- INSERM, UMR-S 839, Institut du Fer à Moulin, Paris, France,Université Pierre and Marie Curie, Paris, France
| | - Corinne Sagné
- CNRS UMR8192-Université Paris Descartes, Paris, France
| | - Stephane Doly
- INSERM, UMR-S 839, Institut du Fer à Moulin, Paris, France,Université Pierre and Marie Curie, Paris, France
| | - Silvina L Diaz
- INSERM, UMR-S 839, Institut du Fer à Moulin, Paris, France,Université Pierre and Marie Curie, Paris, France
| | - Cédric B P Martin
- Université Pierre and Marie Curie, Paris, France,INSERM, U894, Paris, France
| | - Gaelle Angenard
- INSERM, UMR-S 839, Institut du Fer à Moulin, Paris, France,Université Pierre and Marie Curie, Paris, France
| | - Marie-Pascale Martres
- Université Pierre and Marie Curie, Paris, France,INSERM, U952, Paris, France,CNRS UMR7224, Paris, France
| | - Bruno Giros
- Université Pierre and Marie Curie, Paris, France,INSERM, U952, Paris, France,CNRS UMR7224, Paris, France,Department of Psychiatry, Douglas Hospital, McGill University, Montreal, Canada
| | - Michel Hamon
- Université Pierre and Marie Curie, Paris, France,INSERM, U894, Paris, France
| | - Laurence Lanfumey
- Université Pierre and Marie Curie, Paris, France,INSERM, U894, Paris, France
| | - Patricia Gaspar
- INSERM, UMR-S 839, Institut du Fer à Moulin, Paris, France,Université Pierre and Marie Curie, Paris, France,INSERM UMR-S 839, Institut du Fer à Moulin, 17 Rue du Fer à Moulin, 75005, Paris, France, Tel: +331 45 87 61 11, Fax: +331 45 87 61 30, E-mail :
| | - Raymond Mongeau
- Université Pierre and Marie Curie, Paris, France,INSERM, U894, Paris, France
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211
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Serotonin receptor 2A (HTR2A) gene polymorphism predicts treatment response to venlafaxine XR in generalized anxiety disorder. THE PHARMACOGENOMICS JOURNAL 2011; 13:21-6. [DOI: 10.1038/tpj.2011.47] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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212
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Santini M, Klein A, El-Sayed M, Ratner C, Knudsen G, Mikkelsen J, Aznar S. Novelty-induced activity-regulated cytoskeletal-associated protein (Arc) expression in frontal cortex requires serotonin 2A receptor activation. Neuroscience 2011; 190:251-7. [DOI: 10.1016/j.neuroscience.2011.05.048] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 05/12/2011] [Accepted: 05/19/2011] [Indexed: 01/12/2023]
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213
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Huot P, Fox SH, Brotchie JM. The serotonergic system in Parkinson's disease. Prog Neurobiol 2011; 95:163-212. [PMID: 21878363 DOI: 10.1016/j.pneurobio.2011.08.004] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 08/05/2011] [Accepted: 08/15/2011] [Indexed: 01/23/2023]
Abstract
Although the cardinal manifestations of Parkinson's disease (PD) are attributed to a decline in dopamine levels in the striatum, a breadth of non-motor features and treatment-related complications in which the serotonergic system plays a pivotal role are increasingly recognised. Serotonin (5-HT)-mediated neurotransmission is altered in PD and the roles of the different 5-HT receptor subtypes in disease manifestations have been investigated. The aims of this article are to summarise and discuss all published preclinical and clinical studies that have investigated the serotonergic system in PD and related animal models, in order to recapitulate the state of the current knowledge and to identify areas that need further research and understanding.
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Affiliation(s)
- Philippe Huot
- Toronto Western Research Institute, MCL 11-419, Toronto Western Hospital, University Health Network, 399 Bathurst Street, Toronto, Ontario, Canada M5T 2S8
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214
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Morrison KE, Swallows CL, Cooper MA. Effects of dominance status on conditioned defeat and expression of 5-HT1A and 5-HT2A receptors. Physiol Behav 2011; 104:283-90. [PMID: 21362435 PMCID: PMC3118936 DOI: 10.1016/j.physbeh.2011.02.033] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 12/22/2010] [Accepted: 02/22/2011] [Indexed: 12/26/2022]
Abstract
Past experience can alter how individuals respond to stressful events. The brain serotonin system is a key factor modulating stress-related behavior and may contribute to individual variation in coping styles. In this study we investigated whether dominant and subordinate hamsters respond differently to social defeat and whether their behavioral responses are associated with changes in 5-HT1A and 5-HT2A receptor immunoreactivity in several limbic brain regions. We paired weight-matched hamsters in daily aggressive encounters for two weeks so that they formed a stable dominance relationship. We also included controls that were exposed to an empty cage each day for two weeks. Twenty-four hours after the final pairing or empty cage exposure, subjects were socially defeated in 3, 5-min encounters with a more aggressive hamster. Twenty-four hours after social defeat, animals were tested for conditioned defeat in a 5-min social interaction test with a non-aggressive intruder. We collected brains following conditioned defeat testing and performed immunohistochemistry for 5-HT1A and 5-HT2A receptors. We found that dominants showed less submissive and defensive behavior at conditioned defeat testing compared to both subordinates and controls. Additionally, both dominants and subordinates had an increased number of 5-HT1A immunopositive cells in the basolateral amygdala compared to controls. Subordinates also had more 5-HT1A immunopositive cells in the dorsal medial amygdala than did controls. Finally, dominants had fewer 5-HT1A immunopositive cells in the paraventricular nucleus of the hypothalamus compared to controls. Our results indicate that dominant social status results in a blunted conditioned defeat response and a distinct pattern of 5-HT1A receptor expression, which may contribute to resistance to conditioned defeat.
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Affiliation(s)
- Kathleen E Morrison
- Department of Psychology, University of Tennessee, Knoxville, TN 37996, USA.
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215
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The Impact of Long-term Chewing Stimulation Alterations on Anxiety and Cognition in Young Mice*. PROG BIOCHEM BIOPHYS 2011. [DOI: 10.3724/sp.j.1206.2010.00620] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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216
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Involvement of 5-HT2A receptors in MDMA reinforcement and cue-induced reinstatement of MDMA-seeking behaviour. Int J Neuropsychopharmacol 2011; 14:927-40. [PMID: 20942998 DOI: 10.1017/s1461145710001215] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The serotonergic system appears crucial for (±)-3,4-methylenedioxymethamphetamine (MDMA) reinforcing properties. Current evidence indicates that serotonin 5-HT2A receptors (5-HT2ARs) modulate mesolimbic dopamine (DA) activity and several behavioural responses related to the addictive properties of psychostimulants. This study evaluated the role of 5-HT2ARs in MDMA-induced reinforcement and hyperlocomotion, and the reinstatement of MDMA-seeking behaviour. Basal and MDMA-stimulated extracellular levels of DA in the nucleus accumbens (NAc) and serotonin and noradrenaline in the prefrontal cortex were also assessed. Self-administration of MDMA was blunted in 5-HT2AR knockout (KO) mice compared to wild-type (WT) littermates at both doses tested (0.125 and 0.25 mg/kg per infusion). Horizontal locomotion was increased by MDMA (10 and 20 mg/kg i.p.) to a higher extent in KO than in WT mice. DA outflow in the NAc was lower in KO compared to WT mice under basal conditions and after MDMA (20 mg/kg) challenge. In WT mice, MDMA (5 and 10 mg/kg i.p.) priming did not reinstate MDMA-seeking behaviour, while cue-induced reinstatement was prominent. This cue-induced reinstatement was blocked by administration of the selective 5-HT2AR antagonist, SR46349B (eplivanserin) at a dose of 0.5 mg/kg, but not at 0.25 mg/kg. Our results indicate that 5-HT2ARs are crucial for MDMA-induced reinforcement and cue-induced reinstatement of MDMA-seeking behaviour. These effects are probably due to the modulation of mesolimbic dopaminergic activity.
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217
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Lambe EK, Fillman SG, Webster MJ, Shannon Weickert C. Serotonin receptor expression in human prefrontal cortex: balancing excitation and inhibition across postnatal development. PLoS One 2011; 6:e22799. [PMID: 21829518 PMCID: PMC3146513 DOI: 10.1371/journal.pone.0022799] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2011] [Accepted: 07/05/2011] [Indexed: 12/15/2022] Open
Abstract
Serotonin and its receptors (HTRs) play critical roles in brain development and in the regulation of cognition, mood, and anxiety. HTRs are highly expressed in human prefrontal cortex and exert control over prefrontal excitability. The serotonin system is a key treatment target for several psychiatric disorders; however, the effectiveness of these drugs varies according to age. Despite strong evidence for developmental changes in prefrontal Htrs of rodents, the developmental regulation of HTR expression in human prefrontal cortex has not been examined. Using postmortem human prefrontal brain tissue from across postnatal life, we investigated the expression of key serotonin receptors with distinct inhibitory (HTR1A, HTR5A) and excitatory (HTR2A, HTR2C, HTR4, HTR6) effects on cortical neurons, including two receptors which appear to be expressed to a greater degree in inhibitory interneurons of cerebral cortex (HTR2C, HTR6). We found distinct developmental patterns of expression for each of these six HTRs, with profound changes in expression occurring early in postnatal development and also into adulthood. However, a collective look at these HTRs in terms of their likely neurophysiological effects and major cellular localization leads to a model that suggests developmental changes in expression of these individual HTRs may not perturb an overall balance between inhibitory and excitatory effects. Examining and understanding the healthy balance is critical to appreciate how abnormal expression of an individual HTR may create a window of vulnerability for the emergence of psychiatric illness.
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Affiliation(s)
- Evelyn K Lambe
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada.
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218
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Bernhardt V, Hotchkiss MT, Garcia-Reyero N, Escalon BL, Denslow N, Davenport PW. Tracheal occlusion conditioning in conscious rats modulates gene expression profile of medial thalamus. Front Physiol 2011; 2:24. [PMID: 21660287 PMCID: PMC3107442 DOI: 10.3389/fphys.2011.00024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Accepted: 05/16/2011] [Indexed: 11/13/2022] Open
Abstract
The thalamus may be the critical brain area involved in sensory gating and the relay of respiratory mechanical information to the cerebral cortex for the conscious awareness of breathing. We hypothesized that respiratory mechanical stimuli in the form of tracheal occlusions would modulate the gene expression profile of the thalamus. Specifically, it was reasoned that conditioning to the respiratory loading would induce a state change in the medial thalamus consistent with a change in sensory gating and the activation of molecular pathways associated with learning and memory. In addition, respiratory loading is stressful and thus should elicit changes in gene expressions related to stress, anxiety, and depression. Rats were instrumented with inflatable tracheal cuffs. Following surgical recovery, they underwent 10 days (5 days/week) of transient tracheal occlusion conditioning. On day 10, the animals were sacrificed and the brains removed. The medial thalamus was dissected and microarray analysis of gene expression performed. Tracheal obstruction conditioning modulated a total of 661 genes (p < 0.05, log2 fold change ≥0.58), 250 genes were down-regulated and 411 up-regulated. There was a significant down-regulation of GAD1, GAD2 and HTR1A, HTR2A genes. CCK, PRKCG, mGluR4, and KCJN9 genes were significantly up-regulated. Some of these genes have been associated with anxiety and depression, while others have been shown to play a role in switching between tonic and burst firing modes in the thalamus and thus may be involved in gating of the respiratory stimuli. Furthermore, gene ontology and pathway analysis showed a significant modulation of learning and memory pathways. These results support the hypothesis that the medial thalamus is involved in the respiratory sensory neural pathway due to the state change of its gene expression profile following repeated tracheal occlusions.
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Affiliation(s)
- Vipa Bernhardt
- Department of Physiological Sciences, University of Florida Gainesville, FL, USA
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Bernhardt V, Garcia-Reyero N, Vovk A, Denslow N, Davenport PW. Tracheal occlusion modulates the gene expression profile of the medial thalamus in anesthetized rats. J Appl Physiol (1985) 2011; 111:117-24. [PMID: 21527662 DOI: 10.1152/japplphysiol.01317.2010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Conscious awareness of breathing requires the activation of higher brain centers and is believed to be a neural gated process. The thalamus could be responsible for the gating of respiratory sensory information to the cortex. It was reasoned that if the thalamus is the neural gate, then tracheal obstructions will modulate the gene expression profile of the thalamus. Anesthetized rats were instrumented with an inflatable cuff sutured around the trachea. The cuff was inflated to obstruct 2-4 breaths, then deflated for a minimum of 15 breaths. Obstructions were repeated for 10 min followed by immediate dissection of the medial thalamus. Following the occlusion protocol, 588 genes were found to be altered (P < 0.05; log(2) fold change ≥ 0.4), with 327 genes downregulated and 261 genes upregulated. A significant upregulation of the serotonin HTR2A receptor and significant downregulation of the dopamine DRD1 receptor genes were found. A pathway analysis was performed that targeted serotonin and dopamine receptor pathways. The mitogen-activated protein kinase 1 (MAPK1) gene was significantly downregulated. MAPK1 is an inhibitory regulator of HTR2A and facilitatory regulator for DRD1. Downregulation of MAPK1 may be related to the significant upregulation of HTR2A and downregulation of DRD1, suggesting an interaction in the medial thalamus serotonin-dopamine pathway elicited by airway obstruction. These results demonstrate an immediate change in gene expression in thalamic arousal, fear, anxiety motivation-related serotonin and dopamine receptors in response to airway obstruction. The results support the hypothesis that the thalamus is a component in the respiratory mechanosensory neural pathway.
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Affiliation(s)
- Vipa Bernhardt
- Department of Physiological Sciences, University of Florida, Gainesville, FL 32610, USA
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220
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Jacobsen KX, Czesak M, Deria M, Le François B, Albert PR. Region-specific regulation of 5-HT1A receptor expression by Pet-1-dependent mechanisms in vivo. J Neurochem 2011; 116:1066-76. [PMID: 21182526 PMCID: PMC4540595 DOI: 10.1111/j.1471-4159.2010.07161.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Serotonin (5-hydroxytryptamine, 5-HT) neurotransmission is negatively regulated by 5-HT1A autoreceptors on raphe neurons, and is implicated in mood disorders. Pet-1/FEV is an ETS transcription factor expressed exclusively in serotonergic neurons and is essential for serotonergic differentiation, although its regulation of 5-HT receptors has not yet been studied. Here, we show by electrophoretic mobility shift assay that recombinant human Pet-1/FEV binds directly to multiple Pet-1 elements of the human 5-HT1A receptor promoter to enhance its transcriptional activity. In luciferase reporter assays, mutational analysis indicated that while several sites contribute, the Pet-1 site at -1406 bp had the greatest effect on 5-HT1A promoter activity. To address the effect of Pet-1 on 5-HT1A receptor regulation in vivo, we compared the expression of 5-HT1A receptor RNA and protein in Pet-1 null and wild-type littermate mice. In the raphe nuclei of Pet-1-/- mice tryptophan hydroxylase 2 (TPH2) RNA, and 5-HT and TPH immunostaining were greatly reduced, indicating a deficit in 5-HT production. Raphe 5-HT1A RNA and protein levels were also reduced in Pet-1-deficient mice, consistent with an absence of Pet-1-mediated transcriptional enhancement of 5-HT1A autoreceptors in serotonergic neurons. Interestingly, 5-HT1A receptor expression was up-regulated in the hippocampus, but down-regulated in the striatum and cortex. These data indicate that, in addition to transcriptional regulation by Pet-1 in raphe neurons, 5-HT1A receptor expression is regulated indirectly by alterations in 5-HT neurotransmission in a region-specific manner that together may contribute to the aggressive/anxiety phenotype observed in Pet-1 null mice.
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Affiliation(s)
- Kristen X. Jacobsen
- Ottawa Hospital Research Institute (Neuroscience), University of Ottawa, Ottawa, Ontario, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Margaret Czesak
- Ottawa Hospital Research Institute (Neuroscience), University of Ottawa, Ottawa, Ontario, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Mariam Deria
- Ottawa Hospital Research Institute (Neuroscience), University of Ottawa, Ottawa, Ontario, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Brice Le François
- Ottawa Hospital Research Institute (Neuroscience), University of Ottawa, Ottawa, Ontario, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Paul R. Albert
- Ottawa Hospital Research Institute (Neuroscience), University of Ottawa, Ottawa, Ontario, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
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221
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Zhong P, Yan Z. Differential regulation of the excitability of prefrontal cortical fast-spiking interneurons and pyramidal neurons by serotonin and fluoxetine. PLoS One 2011; 6:e16970. [PMID: 21383986 PMCID: PMC3044712 DOI: 10.1371/journal.pone.0016970] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 01/11/2011] [Indexed: 11/19/2022] Open
Abstract
Serotonin exerts a powerful influence on neuronal excitability. In this study, we investigated the effects of serotonin on different neuronal populations in prefrontal cortex (PFC), a major area controlling emotion and cognition. Using whole-cell recordings in PFC slices, we found that bath application of 5-HT dose-dependently increased the firing of FS (fast spiking) interneurons, and decreased the firing of pyramidal neurons. The enhancing effect of 5-HT in FS interneurons was mediated by 5-HT2 receptors, while the reducing effect of 5-HT in pyramidal neurons was mediated by 5-HT1 receptors. Fluoxetine, the selective serotonin reuptake inhibitor, also induced a concentration-dependent increase in the excitability of FS interneurons, but had little effect on pyramidal neurons. In rats with chronic fluoxetine treatment, the excitability of FS interneurons was significantly increased, while pyramidal neurons remained unchanged. Fluoxetine injection largely occluded the enhancing effect of 5-HT in FS interneurons, but did not alter the reducing effect of 5-HT in pyramidal neurons. These data suggest that the excitability of PFC interneurons and pyramidal neurons is regulated by exogenous 5-HT in an opposing manner, and FS interneurons are the major target of Fluoxetine. It provides a framework for understanding the action of 5-HT and antidepressants in altering PFC network activity.
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Affiliation(s)
- Ping Zhong
- Department of Physiology and Biophysics, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, United States of America
| | - Zhen Yan
- Department of Physiology and Biophysics, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York, United States of America
- * E-mail:
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222
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Miyata S, Hirano S, Ohsawa M, Kamei J. Chlorpheniramine exerts anxiolytic-like effects and activates prefrontal 5-HT systems in mice. Psychopharmacology (Berl) 2011; 213:441-52. [PMID: 19823805 DOI: 10.1007/s00213-009-1695-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Accepted: 10/01/2009] [Indexed: 11/30/2022]
Abstract
RATIONALE The traditional antihistamine chlorpheniramine ameliorates panic attacks, phobias, and lowered mood, and this therapeutic effect is independent of the blockade of histamine H(1) receptors. Since chlorpheniramine inhibits the reuptake of serotonin (5-HT), the anxiolytic-like effect of chlorpheniramine may be produced by an increase in serotonergic function. OBJECTIVE To elucidate the mechanisms underlying the anxiolytic-like effects of chlorpheniramine in mice, we examined the involvement of 5-HT systems in the prefrontal cortex that is a crucial region in the regulation of emotional function. RESULTS Chlorpheniramine (0.05-5 mg/kg, i.p.) dose-dependently and significantly decreased the duration of freezing behavior in both the elevated open-platform and conditioned fear tests. The anti-freezing effects of chlorpheniramine (5 mg/kg, i.p.) in these tests were inhibited by pretreatment with the non-selective antagonist at 5-HT receptors, methiothepin (0.01 mg/kg, s.c.). In addition, the local injection of chlorpheniramine (10-100 ng/mouse) and 5-HT (1-10 μg/mouse) into the medial part of the prefrontal cortex (mPFC) dose-dependently and significantly decreased the duration of freezing behavior in the elevated open-platform test. In a microdialysis study, chlorpheniramine (0.5 and 5 mg/kg, i.p.) dose-dependently and significantly increased the extracellular 5-HT level in the mPFC. In addition, the local perfusion of chlorpheniramine (10 and 30 μM), but not of the selective H1 receptor antagonist, cetirizine, into the mPFC markedly increased the extracellular 5-HT level in the mPFC. CONCLUSION The anxiolytic-like effect of chlorpheniramine is produced, at least in part, by the facilitation of serotonergic neurotransmission in the PFC.
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Affiliation(s)
- Shigeo Miyata
- Department of Pathophysiology and Therapeutics, School of Pharmacy and Pharmaceutical Sciences, Hoshi University, Tokyo, Japan
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223
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Phospholipase C, Ca2+, and calmodulin signaling are required for 5-HT2A receptor-mediated transamidation of Rac1 by transglutaminase. Psychopharmacology (Berl) 2011; 213:403-12. [PMID: 20717650 PMCID: PMC3033764 DOI: 10.1007/s00213-010-1984-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Accepted: 07/28/2010] [Indexed: 01/12/2023]
Abstract
RATIONALE Serotonin and especially serotonin 2A (5-HT(2A)) receptor signaling are important in the etiology and treatment of schizophrenia and affective disorders. We previously reported a novel 5-HT(2A) receptor effector, increased transglutaminase (TGase)-catalyzed transamidation, and activation of the small G protein Rac1 in A1A1v cells, a rat embryonic cortical cell line. OBJECTIVES In this study, we explore the signaling pathway involved in 5-HT(2A) receptor-mediated Rac1 transamidation. METHODS A1A1v cells were pretreated with pharmacological inhibitors of phospholipase C (PLC) or calmodulin (CaM), and then stimulated by the 5-HT(2A) receptor agonist, 2,5-dimethoxy-4-iodoamphetamine (DOI). Intracellular Ca(2+) concentration and TGase-modified Rac1 transamidation were monitored. The effect of manipulation of intracellular Ca(2+) by a Ca(2+) ionophore or a chelating agent on Rac1 transamidation was also evaluated. RESULTS In cells pretreated with a PLC inhibitor U73122, DOI-stimulated increases in the intracellular Ca(2+) concentration and TGase-modified Rac1 were significantly attenuated as compared to those pretreated with U73343, an inactive analog. The membrane-permeant Ca(2+) chelator, BAPTA-AM strongly reduced TGase-catalyzed Rac1 transamidation upon DOI stimulation. Conversely, the Ca(2+) ionophore ionomycin, at a concentration that induced an elevation of cytosolic Ca(2+) to a level comparable to cells treated with DOI, produced an increase in TGase-modified Rac1 without 5-HT(2A) receptor activation. Moreover, the CaM inhibitor W-7, significantly decreased Rac1 transamidation in a dose-dependent manner in DOI-treated cells. CONCLUSIONS These results indicate that 5-HT(2A) receptor-coupled PLC activation and subsequent Ca(2+) and CaM signaling are necessary for TGase-catalyzed Rac1 transamidation, and an increase in intracellular Ca(2+) is sufficient to induce Rac1 transamidation.
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224
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Kim SS, Wang H, Li XY, Chen T, Mercaldo V, Descalzi G, Wu LJ, Zhuo M. Neurabin in the anterior cingulate cortex regulates anxiety-like behavior in adult mice. Mol Brain 2011; 4:6. [PMID: 21247477 PMCID: PMC3037880 DOI: 10.1186/1756-6606-4-6] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 01/19/2011] [Indexed: 12/11/2022] Open
Abstract
Affective disorders, which include anxiety and depression, are highly prevalent and have overwhelming emotional and physical symptoms. Despite human brain imaging studies, which have implicated the prefrontal cortex including the anterior cingulate cortex (ACC), little is known about the ACC in anxiety disorders. Here we show that the ACC does modulate anxiety-like behavior in adult mice, and have identified a protein that is critical for this modulation. Absence of neurabin, a cytoskeletal protein, resulted in reduced anxiety-like behavior and increased depression-like behavior. Selective inhibition of neurabin in the ACC reproduced the anxiety but not the depression phenotype. Furthermore, loss of neurabin increased the presynaptic release of glutamate and cingulate neuronal excitability. These findings reveal novel roles of the ACC in anxiety disorders, and provide a new therapeutic target for the treatment of anxiety disorders.
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Affiliation(s)
- Susan S Kim
- Department of Physiology, Faculty of Medicine, University of Toronto Centre for the Study of Pain, ON, Canada
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225
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Cerebral metabolic responses to 5-HT2A/C receptor activation in mice with genetically modified serotonin transporter (SERT) expression. Eur Neuropsychopharmacol 2011; 21:117-28. [PMID: 21093224 DOI: 10.1016/j.euroneuro.2010.10.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Revised: 10/15/2010] [Accepted: 10/17/2010] [Indexed: 11/21/2022]
Abstract
Variation in the human serotonin transporter gene (hSERT; 5-HTT) resulting in a life-long alteration in SERT function influences anxiety and the risk of developing affective disorders. The mechanisms underlying the influence of the hSERT gene on these phenotypes remain unclear but may involve altered 5-HT receptor function. Here we characterise the cerebral metabolic response to 5-HT(2A/C) receptor activation in two transgenic mouse models of altered SERT function, SERT knock-out (SERT KO) and hSERT over-expressing (hSERT OE) mice, to test the hypothesis that genetically mediated variability in SERT expression alters 5-HT(2A/C) function. We found that a constitutive increase in SERT expression (hSERT OE) enhanced, whereas a constitutive decrease in SERT expression (SERT KO) attenuated, 5-HT(2A/C) function. Therefore, altered 5-HT(2A/C) receptor functioning in response to hSERT gene variation may contribute to its influence on affective phenotypes.
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226
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Effects of yokukansan on anxiety-like behavior in a rat model of cerebrovascular dementia. J Nat Med 2010; 65:275-81. [PMID: 21152992 DOI: 10.1007/s11418-010-0487-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2010] [Accepted: 10/23/2010] [Indexed: 01/10/2023]
Abstract
Behavioral and psychological symptoms of dementia (BPSD) are commonly seen in patients with dementia. Current pharmacological approaches to treatment are inadequate, despite the availability of serotonergic agents to ameliorate anxiety, one of the symptoms of BPSD. The herbal medicine yokukansan has been demonstrated to improve BPSD in a randomized, single-blinded, placebo-controlled study. However, the mechanisms of the anxiolytic effect of yokukansan have not been clarified. There are also no reports on the anxiolytic effect of yokukansan in cerebrovascular ischemia models. In this study, we examined whether rats subjected to repeated cerebral ischemia exhibited anxiety-like behavior in a plus-maze task, a light/dark box test and an open-field task. We then investigated the effect of yokukansan on anxiety-like behavior in ischemic rats. Repeated ischemia was induced by the four-vessel occlusion method in which a 10-min ischemic episode was repeated once after 60 min. Yokukansan was orally administered once a day for 14 days from 7 days before ischemia induction. The last administration was performed 1 h before the behavioral experiments. The ischemic rats showed anxiety-like behavior in all three tasks, suggesting that this rat may be a good model for anxiety in cerebrovascular dementia. Yokukansan exhibited anxiolytic effects on the anxiety-like behavior in rats subjected to repeated cerebral ischemia, and exerted antagonistic effects on the wet-dog shakes induced by 1-(2,5-dimethoxy-4-indophenyl)-2-amino propane, a serotonin receptor (5-HT(2A)) agonist. This study revealed that yokukansan shows anxiolytic effects not only in normal animals but also in cerebrovascular model rats.
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227
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Huang M, Dai J, Meltzer HY. 5-HT(2A) and 5-HT(2C) receptor stimulation are differentially involved in the cortical dopamine efflux-Studied in 5-HT(2A) and 5-HT(2C) genetic mutant mice. Eur J Pharmacol 2010; 652:40-5. [PMID: 21118683 DOI: 10.1016/j.ejphar.2010.10.094] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 10/13/2010] [Accepted: 10/31/2010] [Indexed: 02/03/2023]
Abstract
Both 5-HT(2A) and 5-HT(2C) receptors modulate cortical dopamine efflux, but in opposite directions. We have now compared the ability of the three 5-HT(2A/2C) receptor agonists, DOI (R(-)-2,5-dimethoxy-4-iodoamphetamine), mCPP (meta-chlorophenylpiperazine) and MK-212 (6-Chloro-2-(piperazinyl) pyrazine), to modulate cortical dopamine efflux in 5-HT(2A) and 5-HT(2C) genetic mutant mice. In the 5-HT(2A) mice, the preferential 5-HT(2A) receptor agonist DOI (2.5mg/kg, s.c.) induced a slight but significant increase in cortical dopamine efflux only in the wild type (WT) mice; MK-212 (2.5mg/kg) reduced dopamine efflux in both WT and receptor knockout (KO) mice; moreover, MCPP, 2.5mg/kg, had no effect in either types. In 5-HT(2C) mice, DOI increased dopamine efflux in both types; while MK-212 decreased dopamine efflux in the WT, but not the receptor KO mice. These results provide new evidence that 5-HT(2A) receptor stimulation enhances and 5-HT(2C) receptor stimulation inhibits cortical dopamine efflux, and suggest the effects of DOI, MK-212 and mCPP on the cortical dopamine efflux are due to their different abilities on 5-HT(2A) and 5-HT(2C) receptors stimulation. Of these three agents, only DOI, the more selective 5-HT(2A) receptor agonist, is hallucinogenic. The absence of hallucinations with mCPP may be due to its relatively more potent 5-HT(2C) receptor agonist effect, inhibiting the ability of mCPP to enhance dopamine efflux in cortical and perhaps limbic regions as well. The present data provide additional evidence that hallucinations are due, in part, to 5-HT(2A) rather than 5-HT(2C) receptor stimulation. These findings suggest that 5-HT(2C) receptor agonists may be useful as antipsychotics, consistent with previous suggestions.
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Affiliation(s)
- Mei Huang
- Division of Psychopharcology, Department of Psychiatry, Vanderbilt University School of Medicine, TN, USA
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228
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Il-Han J, Janes T, Lukowiak K. The role of serotonin in the enhancement of long-term memory resulting from predator detection in Lymnaea. J Exp Biol 2010; 213:3603-14. [DOI: 10.1242/jeb.048256] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
SUMMARY
Serotonergic systems play important roles in modulating stress-induced arousal and vigilance behaviours. The pond snail, Lymnaea, shows multiple defensive vigilance behaviours in response to the stress associated with predator detection. Predator detection elicited by crayfish effluent (CE), increases the time to re-emerge from the shell and enhances the shadow withdrawal response. More importantly, in Lymnaea, CE enhances the ability to form long-term memory (LTM). We investigated the role of the serotonergic system in these anti-predator responses in Lymnaea. Using a serotonin-receptor antagonist, mianserin, we found that two defensive vigilance behaviours (e.g. increasing the time to re-emerge from their shell and shadow response) elicited by CE were not observed when the serotonergic system was disrupted. Also, methysergide, another serotonin antagonist, blocked the enhanced LTM formation after training in CE. Importantly, mianserin did not alter LTM formation in pond water (PW). These data suggest that a serotonergic system is activated only when Lymnaea detect a predator. When snails were trained in CE using a training procedure that in PW produces a 24-h LTM, a more persistent form of LTM (5 days) occurred. This more persistent form of LTM was abolished after mianserin treatment. Increasing 5-HT levels in the snail by the injection of 5-HT was also associated with enhanced LTM formation. Lastly, we tested whether the osphradium is implicated in CE detection and subsequent enhanced formation of LTM. Cutting the osphradial nerve to the CNS resulted in the loss of the ability to form enhanced LTM in CE. Together, these findings support the hypothesis that the serotonergic system plays a key role in modulating the predator-induced stress responses in Lymnaea.
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Affiliation(s)
- Jae Il-Han
- Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, 3330 Hospital Drive, NW Calgary, AB T2N 4N1, Canada
| | - Tara Janes
- Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, 3330 Hospital Drive, NW Calgary, AB T2N 4N1, Canada
| | - Ken Lukowiak
- Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, 3330 Hospital Drive, NW Calgary, AB T2N 4N1, Canada
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Enhanced function of prefrontal serotonin 5-HT(2) receptors in a rat model of psychiatric vulnerability. J Neurosci 2010; 30:12138-50. [PMID: 20826676 DOI: 10.1523/jneurosci.3245-10.2010] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Prefrontal serotonin 5-HT(2) receptors have been linked to the pathogenesis and treatment of affective disorders, yet their function in psychiatric vulnerability is not known. Here, we examine the effects of 5-HT(2) receptors in a rat model of psychiatric vulnerability using electrophysiology, gene expression, and behavior. Following the early stress of chronic maternal separation, we found that serotonin has atypical 5-HT(2) receptor-mediated excitatory effects in the adult prefrontal cortex that were blocked by the 5-HT(2A) receptor antagonist MDL 100907. In the absence of a serotonergic agonist, the intrinsic excitability of the prefrontal cortex was not enhanced relative to controls. Yet, in response to stimulation of 5-HT(2) receptors, adult animals with a history of early stress exhibit heightened prefrontal network activity in vitro, enhanced immediate early gene expression in vivo, and potentiated head shake behavior. These changes arise in the absence of any major alteration of prefrontal 5-HT(2A/C) mRNA expression or 5-HT(2) receptor binding. Our microarray results and quantitative PCR validation provide insight into the molecular changes that accompany such enhanced 5-HT(2) receptor function in adult animals following early stress. We observed persistent prefrontal transcriptome changes, with significant enrichment of genes involved in cellular developmental processes, regulation of signal transduction, and G-protein signaling. Specific genes regulated by early stress were validated in an independent cohort, and several altered genes were normalized by chronic blockade of 5-HT(2) receptors in adulthood. Together, our results demonstrate enhanced prefrontal 5-HT(2) receptor function and persistent alterations in prefrontal gene expression in a rat model of psychiatric vulnerability.
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230
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Oxytocin mediates the antidepressant effects of mating behavior in male mice. Neurosci Res 2010; 68:151-3. [DOI: 10.1016/j.neures.2010.06.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2009] [Revised: 06/11/2010] [Accepted: 06/14/2010] [Indexed: 01/18/2023]
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231
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Lam DD, Garfield AS, Marston OJ, Shaw J, Heisler LK. Brain serotonin system in the coordination of food intake and body weight. Pharmacol Biochem Behav 2010; 97:84-91. [PMID: 20837046 DOI: 10.1016/j.pbb.2010.09.003] [Citation(s) in RCA: 179] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Revised: 08/02/2010] [Accepted: 09/06/2010] [Indexed: 11/30/2022]
Abstract
An inverse relationship between brain serotonin and food intake and body weight has been known for more than 30 years. Specifically, augmentation of brain serotonin inhibits food intake, while depletion of brain serotonin promotes hyperphagia and weight gain. Through the decades, serotonin receptors have been identified and their function in the serotonergic regulation of food intake clarified. Recent refined genetic studies now indicate that a primary mechanism through which serotonin influences appetite and body weight is via serotonin 2C receptor (5-HT(2C)R) and serotonin 1B receptor (5-HT(1B)R) influencing the activity of endogenous melanocortin receptor agonists and antagonists at the melanocortin 4 receptor (MC4R). However, other mechanisms are also possible and the challenge of future research is to delineate them in the complete elucidation of the complex neurocircuitry underlying the serotonergic control of appetite and body weight.
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Affiliation(s)
- Daniel D Lam
- Department of Pharmacology, University of Cambridge, Cambridge, UK
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232
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Fox MA, French HT, LaPorte JL, Blackler AR, Murphy DL. The serotonin 5-HT(2A) receptor agonist TCB-2: a behavioral and neurophysiological analysis. Psychopharmacology (Berl) 2010; 212:13-23. [PMID: 19823806 DOI: 10.1007/s00213-009-1694-1] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Accepted: 09/10/2009] [Indexed: 12/16/2022]
Abstract
RATIONALE There are few reports on the high-affinity 5-HT(2A) agonist (4-Bromo-3,6-dimethoxybenzocyclobuten-1-yl)methylamine hydrobromide (TCB-2). OBJECTIVES Here we provide the first behavioral and neurophysiological profile of TCB-2 in C57BL/6J mice, with direct comparisons to the 5-HT(2A/2C) agonist (+/-)-2,5-dimethoxy-4-iodophenyl-2-aminopropane (DOI), in addition to determinations of 5-HT(2A) mediation via pretreatment with the selective 5-HT(2A) antagonist MDL 11,939. RESULTS In a dose-dependent manner, TCB-2 induced head twitches, decreased food consumption in food-deprived mice, induced hypothermia, and increased corticosterone levels, with no effects on locomotor activity or anxiety-like behaviors in the open field. Similar effects were observed in side-by-side dose-response comparisons with DOI; although at the highest dose tested (5.0 mg/kg), TCB-2 induced significantly fewer head twitches, and a significantly enhanced hypothermic response, versus DOI. Pretreatment with MDL 11,939 blocked head twitches and temperature change following TCB-2 and DOI, confirming 5-HT(2A) mediation of these responses. Although MDL 11,939 pretreatment blocked DOI-induced suppression of feeding, MDL 11,939 had no effect on TCB-2-induced suppression of feeding. Previous studies show that 5-HT(2A) function is altered by changes in serotonin transporter (SERT) expression and function. In SERT knockout (-/-) mice, TCB-2-induced head twitches and hypothermia were greatly diminished compared to SERT wild-type (+/+) mice. CONCLUSIONS The current studies are important, as they are the first to assess the effects of TCB-2 in mice, and are among the first to report the behavioral and neurophysiological effects of this conformationally restricted phenethylamine analog compound, which has 65-fold greater effects on signaling via the phosphoinositide versus arachidonic acid pathways.
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Affiliation(s)
- Meredith A Fox
- Laboratory of Clinical Science, National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892-1264, USA.
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Lockridge A, Su J, Yuan LL. Abnormal 5-HT modulation of stress behaviors in the Kv4.2 knockout mouse. Neuroscience 2010; 170:1086-97. [PMID: 20801198 DOI: 10.1016/j.neuroscience.2010.08.047] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Revised: 08/17/2010] [Accepted: 08/21/2010] [Indexed: 10/19/2022]
Abstract
The Kv4.2 gene codes for an essential subunit of voltage-gated A-type potassium channels that are involved in dendritic signal integration and synaptic plasticity. Detailed cellular characterization in CA1 pyramidal neurons of the hippocampus has shown that knocking out the Kv4.2 gene increases neuronal excitability and promotes long-term potentiation. However, the overall behavioral consequences of these modifications have not been fully explored. Given the growing connection between neuronal plasticity and affect processing in the hippocampus and other Kv4.2 expressing regions, we proposed to investigate whether the absence of this gene would alter the stress response of mice to the forced swimming and tail suspension tests (TSTs) for depression-like behavior. Kv4.2 knockout (KO) mice, generated in the 129SvEv background, demonstrated elevated immobility and a loss of swimming, as well as antidepressant resistance to the selective 5-HT reuptake inhibitor fluoxetine (FLX). Characterization of a relatively new head movement behavior category, responsive to serotonergic treatment in wildtype (WT) mice, supported conclusions of abnormal 5-HT modulation. Electrophysiology recordings in the prefrontal cortex showed a blunting of postsynaptic response to direct 5-HT application following a single period of swim stress only in the animals without the Kv4.2 subunit. Based on our findings, we hypothesize that Kv4.2 KO mice may have an exaggerated 5-HT response to stress leading to a premature desensitization of postsynaptic receptors and a loss of continued behavior modulation. These results may shed some light on the involvement of A-type potassium channels in the effective action of selective serotonin reuptake inhibitor (SSRI) antidepressants.
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Affiliation(s)
- A Lockridge
- Department of Neuroscience, University of Minnesota, Minneapolis, MN, USA
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234
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Vollenweider FX, Kometer M. The neurobiology of psychedelic drugs: implications for the treatment of mood disorders. Nat Rev Neurosci 2010; 11:642-51. [DOI: 10.1038/nrn2884] [Citation(s) in RCA: 398] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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235
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Weber ET, Andrade R. Htr2a Gene and 5-HT(2A) Receptor Expression in the Cerebral Cortex Studied Using Genetically Modified Mice. Front Neurosci 2010; 4. [PMID: 20802802 PMCID: PMC2928707 DOI: 10.3389/fnins.2010.00036] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Accepted: 05/12/2010] [Indexed: 11/26/2022] Open
Abstract
Serotonin receptors of the 5-HT2A subtype are robustly expressed in the cerebral cortex where they have been implicated in the pathophysiology and therapeutics of mental disorders and the actions of hallucinogens. Much less is known, however, about the specific cell types expressing 5-HT2A receptors in cortex. In the current study we use immunohistochemical and electrophysiological approaches in genetically modified mice to address the expression of the Htr2a gene and 5-HT2A receptors in cortex. We first use an EGFP-expressing BAC transgenic mice and identify three main Htr2A gene expressing neuronal populations in cortex. The largest of these cell populations corresponds to layer V pyramidal cells of the anterior cortex, followed by GABAergic interneurons of the middle layers, and non-pyramidal cells of the subplate/Layer VIb. We then use 5-HT2A receptor knockout mice to identify an antibody capable of localizing 5-HT2A receptors in brain and use it to map these receptors. We find strong laminar expression of 5-HT2A receptors in cortex, especially along a diffuse band overlaying layer Va. This band exhibits a strong anteroposterior gradient that closely matches the localization of Htr2A expressing pyramidal cells of layer V. Finally we use electrophysiological and immunohistochemical approaches to show that most, but not all, GABAergic interneurons of the middle layers are parvalbumin expressing Fast-spiking interneurons and that these cells are depolarized and excited by serotonin, most likely through the activation of 5-HT2A receptors. These results clarify and extend our understanding of the cellular distribution of 5-HT2A receptors in the cerebral cortex.
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Affiliation(s)
- Elaine T Weber
- Department of Pharmacology, Wayne State University School of Medicine Detroit, MI, USA
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236
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Aznar S, Klein AB, Santini MA, Knudsen GM, Henn F, Gass P, Vollmayr B. Aging and depression vulnerability interaction results in decreased serotonin innervation associated with reduced BDNF levels in hippocampus of rats bred for learned helplessness. Synapse 2010; 64:561-5. [DOI: 10.1002/syn.20773] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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237
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Klein AB, Santini MA, Aznar S, Knudsen GM, Rios M. Changes in 5-HT2A-mediated behavior and 5-HT2A- and 5-HT1A receptor binding and expression in conditional brain-derived neurotrophic factor knock-out mice. Neuroscience 2010; 169:1007-16. [PMID: 20576498 DOI: 10.1016/j.neuroscience.2010.05.054] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 05/17/2010] [Accepted: 05/23/2010] [Indexed: 10/19/2022]
Abstract
Changes in brain-derived neurotrophic factor (BDNF) expression have been implicated in the etiology of psychiatric disorders. To investigate pathological mechanisms elicited by perturbed BDNF signaling, we examined mutant mice with central depletion of BDNF (BDNF(2L/2LCk-cre)). A severe impairment specific for the serotonin 2A receptor (5-HT(2A)R) in prefrontal cortex was described previously in these mice. This is of much interest, as 5-HT(2A)Rs have been linked to neuropsychiatric disorders and anxiety-related behavior. Here we further characterized the serotonin receptor alterations triggered by BDNF depletion. 5-HT(2A) ([(3)H]-MDL100907) and 5-HT(1A) ([(3)H]-WAY100635) receptor autoradiography revealed site-specific alterations in BDNF mutant mice. They exhibited lower 5-HT(2A) receptor binding in frontal cortex but increased binding in hippocampus. Additionally, 5-HT(1A) receptor binding was decreased in hippocampus of BDNF mutants, but unchanged in frontal cortex. Molecular analysis indicated corresponding changes in 5-HT(2A) and 5-HT(1A) mRNA expression but normal 5-HT(2C) content in these brain regions in BDNF(2L/2LCk-cre) mice. We investigated whether the reduction in frontal 5-HT(2A)R binding was reflected in reduced functional output in two 5-HT(2A)-receptor mediated behavioral tests, the head-twitch response (HTR) and the ear-scratch response (ESR). BDNF(2L/2LCk-cre) mutants treated with the 5-HT(2A) receptor agonist (+/-)-2,5-dimethoxy-4-iodoamphetamine (DOI) showed a clearly diminished ESR but no differences in HTR compared to wildtypes. These findings illustrate the context-dependent effects of deficient BDNF signaling on the 5-HT receptor system and 5-HT(2A)-receptor functional output.
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Affiliation(s)
- A B Klein
- Neurobiology Research Unit and Center for Integrated and Molecular Brain Imaging, Rigshospitalet and University of Copenhagen, Copenhagen, Denmark.
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238
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239
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Tanaka KF, Ahmari SE, Leonardo ED, Richardson-Jones JW, Budreck EC, Scheiffele P, Sugio S, Inamura N, Ikenaka K, Hen R. Flexible Accelerated STOP Tetracycline Operator-knockin (FAST): a versatile and efficient new gene modulating system. Biol Psychiatry 2010; 67:770-3. [PMID: 20163789 PMCID: PMC2969181 DOI: 10.1016/j.biopsych.2009.12.020] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 12/17/2009] [Accepted: 12/18/2009] [Indexed: 10/19/2022]
Abstract
We created the Flexible Accelerated STOP Tetracycline Operator (tetO)-knockin (FAST) system, an efficient method for manipulating gene expression in vivo to rapidly screen animal models of disease. A single gene targeting event yields two distinct knockin mice-STOP-tetO and tetO knockin-that permit generation of multiple strains with variable expression patterns: 1) knockout, 2) Cre-mediated rescue, 3) tetracycline-controlled transcriptional activator (tTA)-mediated misexpression, 4) tetracycline-controlled transcriptional activator (tTA)-mediated overexpression, and 5) tetracycline-controlled transcriptional silencer (tTS)-mediated conditional knockout/knockdown. Using the FAST system, multiple gain-of-function and loss-of-function strains can therefore be generated on a time scale not previously achievable. These strains can then be screened for clinically relevant abnormalities. We demonstrate the flexibility and broad applicability of the FAST system by targeting several genes encoding proteins implicated in neuropsychiatric disorders: Mlc1, neuroligin 3, the serotonin 1A receptor, and the serotonin 1B receptor.
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Affiliation(s)
- Kenji F. Tanaka
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki Aichi 444-8787, Japan, Department of Physiological Sciences, School of Life Sciences, The Graduate University for Advanced Studies (SOKENDAI), Kanagawa 240-0193, Japan, Departments of Neuroscience, Pharmacology & Psychiatry, Columbia University, College of Physicians & Surgeons, New York, NY 10032-2695
| | - Susanne E. Ahmari
- Departments of Neuroscience, Pharmacology & Psychiatry, Columbia University, College of Physicians & Surgeons, New York, NY 10032-2695
| | - E. David Leonardo
- Departments of Neuroscience, Pharmacology & Psychiatry, Columbia University, College of Physicians & Surgeons, New York, NY 10032-2695
| | - Jesse W. Richardson-Jones
- Departments of Neuroscience, Pharmacology & Psychiatry, Columbia University, College of Physicians & Surgeons, New York, NY 10032-2695
| | - Elaine C. Budreck
- Department of Cell Biology, Biozentrum University of Basel, 4056 Basel, Switzerland
| | - Peter Scheiffele
- Department of Cell Biology, Biozentrum University of Basel, 4056 Basel, Switzerland
| | - Shouta Sugio
- Department of Physiological Sciences, School of Life Sciences, The Graduate University for Advanced Studies (SOKENDAI), Kanagawa 240-0193, Japan
| | - Naoko Inamura
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki Aichi 444-8787, Japan
| | - Kazuhiro Ikenaka
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences, Okazaki Aichi 444-8787, Japan, Department of Physiological Sciences, School of Life Sciences, The Graduate University for Advanced Studies (SOKENDAI), Kanagawa 240-0193, Japan
| | - René Hen
- Departments of Neuroscience, Pharmacology & Psychiatry, Columbia University, College of Physicians & Surgeons, New York, NY 10032-2695
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240
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Magalhaes AC, Holmes KD, Dale LB, Comps-Agrar L, Lee D, Yadav PN, Drysdale L, Poulter MO, Roth BL, Pin JP, Anisman H, Ferguson SSG. CRF receptor 1 regulates anxiety behavior via sensitization of 5-HT2 receptor signaling. Nat Neurosci 2010; 13:622-9. [PMID: 20383137 PMCID: PMC2862362 DOI: 10.1038/nn.2529] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2010] [Accepted: 03/04/2010] [Indexed: 12/13/2022]
Abstract
Stress and anxiety disorders are risk factors for depression and these behaviors are modulated by corticotrophin-releasing factor receptor 1 (CRFR1) and serotonin receptor (5-HT(2)R). However, the potential behavioral and cellular interaction between these two receptors is unclear. We found that pre-administration of corticotrophin-releasing factor (CRF) into the prefrontal cortex of mice enhanced 5-HT(2)R-mediated anxiety behaviors in response to 2,5-dimethoxy-4-iodoamphetamine. In both heterologous cell cultures and mouse cortical neurons, activation of CRFR1 also enhanced 5-HT(2) receptor-mediated inositol phosphate formation. CRFR1-mediated increases in 5-HT(2)R signaling were dependent on receptor internalization and receptor recycling via rapid recycling endosomes, resulting in increased expression of 5-HT(2)R on the cell surface. Sensitization of 5-HT(2)R signaling by CRFR1 required intact PDZ domain-binding motifs at the end of the C-terminal tails of both receptor types. These data suggest a mechanism by which CRF, a peptide known to be released by stress, enhances anxiety-related behavior via sensitization of 5-HT(2)R signaling.
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Affiliation(s)
- Ana C Magalhaes
- J. Allyn Taylor Centre for Cell Biology, Molecular Brain Research Group, Robarts Research and the Department of Physiology & Pharmacology, The University of Western Ontario, London, Ontario, Canada
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241
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Barbalat G, Domenech P, Vernet M, Fourneret P. Approche neuroéconomique de la prise de risque à l’adolescence. Encephale 2010; 36:147-54. [DOI: 10.1016/j.encep.2009.06.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Accepted: 06/05/2009] [Indexed: 11/16/2022]
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242
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Canal CE, Olaghere da Silva UB, Gresch PJ, Watt EE, Sanders-Bush E, Airey DC. The serotonin 2C receptor potently modulates the head-twitch response in mice induced by a phenethylamine hallucinogen. Psychopharmacology (Berl) 2010; 209:163-74. [PMID: 20165943 PMCID: PMC2868321 DOI: 10.1007/s00213-010-1784-0] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Accepted: 01/18/2010] [Indexed: 12/25/2022]
Abstract
RATIONALE Hallucinogenic serotonin 2A (5-HT(2A)) receptor partial agonists, such as (+ or -)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride (DOI), induce a frontal cortex-dependent head-twitch response (HTR) in rodents, a behavioral proxy of a hallucinogenic response that is blocked by 5-HT(2A) receptor antagonists. In addition to 5-HT(2A) receptors, DOI and most other serotonin-like hallucinogens have high affinity and potency as partial agonists at 5-HT(2C) receptors. OBJECTIVES We tested for involvement of 5-HT(2C) receptors in the HTR induced by DOI. RESULTS Comparison of 5-HT(2C) receptor knockout and wild-type littermates revealed an approximately 50% reduction in DOI-induced HTR in knockout mice. Also, pretreatment with either the 5-HT(2C) receptor antagonist SB206553 or SB242084 eradicated a twofold difference in DOI-induced HTR between the standard inbred mouse strains C57BL/6J and DBA/2J, and decreased the DOI-induced HTR by at least 50% in both strains. None of several measures of 5-HT(2A) receptors in frontal cortex explained the strain difference, including 5-HT(2A) receptor density, Galpha(q) or Galpha(i/o) protein levels, phospholipase C activity, or DOI-induced expression of Egr1 and Egr2. 5-HT(2C) receptor density in the brains of C57BL/6J and DBA/2J was also equivalent, suggesting that 5-HT(2C) receptor-mediated intracellular signaling or other physiological modulators of the HTR may explain the strain difference in response to DOI. CONCLUSIONS We conclude that the HTR to DOI in mice is strongly modulated by 5-HT(2C) receptor activity. This novel finding invites reassessment of hallucinogenic mechanisms involving 5-HT(2) receptors.
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MESH Headings
- Aminopyridines/pharmacology
- Amphetamines/pharmacology
- Animals
- Autoradiography
- Behavior, Animal
- Binding Sites
- Blotting, Western
- Brain/drug effects
- Brain/metabolism
- Dose-Response Relationship, Drug
- Drug Partial Agonism
- Early Growth Response Protein 1/genetics
- Early Growth Response Protein 2/genetics
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- GTP-Binding Protein alpha Subunits, Gq-G11/metabolism
- Hallucinogens/pharmacology
- Head Movements/drug effects
- Indoles/pharmacology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Inbred DBA
- Mice, Knockout
- Pyridines/pharmacology
- RNA, Messenger/metabolism
- Receptor, Serotonin, 5-HT2C/deficiency
- Receptor, Serotonin, 5-HT2C/drug effects
- Receptor, Serotonin, 5-HT2C/genetics
- Serotonin Antagonists/pharmacology
- Serotonin Receptor Agonists/pharmacology
- Species Specificity
- Type C Phospholipases/metabolism
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243
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Huot P, Johnston TH, Darr T, Hazrati LN, Visanji NP, Pires D, Brotchie JM, Fox SH. Increased 5-HT2Areceptors in the temporal cortex of parkinsonian patients with visual hallucinations. Mov Disord 2010; 25:1399-408. [DOI: 10.1002/mds.23083] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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244
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eIF2alpha Phosphorylation-dependent translation in CA1 pyramidal cells impairs hippocampal memory consolidation without affecting general translation. J Neurosci 2010; 30:2582-94. [PMID: 20164343 DOI: 10.1523/jneurosci.3971-09.2010] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Protein synthesis inhibitor antibiotics are widely used to produce amnesia, and have been recognized to inhibit general or global mRNA translation in the basic translational machinery. For instance, anisomycin interferes with protein synthesis by inhibiting peptidyl transferase or the 80S ribosomal function. Therefore, de novo general or global protein synthesis has been thought to be necessary for long-term memory formation. However, it is unclear which mode of translation-gene-specific translation or general/global translation-is actually crucial for the memory consolidation process in mammalian brains. Here, we generated a conditional transgenic mouse strain in which double-strand RNA-dependent protein kinase (PKR)-mediated phosphorylation of eIF2alpha, a key translation initiation protein, was specifically increased in hippocampal CA1 pyramidal cells by the chemical inducer AP20187. Administration of AP20187 significantly increased activating transcription factor 4 (ATF4) translation and concomitantly suppressed CREB-dependent pathways in CA1 cells; this led to impaired hippocampal late-phase LTP and memory consolidation, with no obvious reduction in general translation. Conversely, inhibition of general translation by low-dose anisomycin failed to block hippocampal-dependent memory consolidation. Together, these results indicated that CA1-restricted genetic manipulation of particular mRNA translations is sufficient to impair the consolidation and that consolidation of memories in CA1 pyramidal cells through eIF2alpha dephosphorylation depends more on transcription/translation of particular genes than on overall levels of general translation. The present study sheds light on the critical importance of gene-specific translations for hippocampal memory consolidation.
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245
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VGLUT3 (vesicular glutamate transporter type 3) contribution to the regulation of serotonergic transmission and anxiety. J Neurosci 2010; 30:2198-210. [PMID: 20147547 DOI: 10.1523/jneurosci.5196-09.2010] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Three different subtypes of H(+)-dependent carriers (named VGLUT1-3) concentrate glutamate into synaptic vesicles before its exocytotic release. Neurons using other neurotransmitter than glutamate (such as cholinergic striatal interneurons and 5-HT neurons) express VGLUT3. It was recently reported that VGLUT3 increases acetylcholine vesicular filling, thereby, stimulating cholinergic transmission. This new regulatory mechanism is herein designated as vesicular-filling synergy (or vesicular synergy). In the present report, we found that deletion of VGLUT3 increased several anxiety-related behaviors in adult and in newborn mice as early as 8 d after birth. This precocious involvement of a vesicular glutamate transporter in anxiety led us to examine the underlying functional implications of VGLUT3 in 5-HT neurons. On one hand, VGLUT3 deletion caused a significant decrease of 5-HT(1A)-mediated neurotransmission in raphe nuclei. On the other hand, VGLUT3 positively modulated 5-HT transmission of a specific subset of 5-HT terminals from the hippocampus and the cerebral cortex. VGLUT3- and VMAT2-positive serotonergic fibers show little or no 5-HT reuptake transporter. These results unravel the existence of a novel subset of 5-HT terminals in limbic areas that might play a crucial role in anxiety-like behaviors. In summary, VGLUT3 accelerates 5-HT transmission at the level of specific 5-HT terminals and can exert an inhibitory control at the raphe level. Furthermore, our results suggest that the loss of VGLUT3 expression leads to anxiety-associated behaviors and should be considered as a potential new target for the treatment of this disorder.
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246
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Li Y, Huang XF, Deng C, Meyer B, Wu A, Yu Y, Ying W, Yang GY, Yenari MA, Wang Q. Alterations in 5-HT2A receptor binding in various brain regions among 6-hydroxydopamine-induced Parkinsonian rats. Synapse 2010; 64:224-30. [PMID: 19862688 DOI: 10.1002/syn.20722] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The serotonergic system has close interactions with the dopaminergic system and is strongly implicated in the pathophysiological mechanisms and therapeutic paradigms of Parkinson's disease (PD). This study aims to investigate regional changes in 5-hydroxytryptamine (5-HT) 2A receptors in the rat brain 3 weeks after unilateral medial forebrain bundle lesion by 6-hydroxydopamine (6-OHDA). 5-HT 2A receptor distributions and alterations in the postmortem rat brain were detected by [(3)H]ketanserin-binding autoradiography. In the 6-OHDA-induced Parkinson's rat model, nigrostriatal dopaminergic neuron loss significantly mediated the decreased [(3)H]ketanserin binding, predominantly in the agranular insular cortex (17.3%, P = 0.03), cingulate cortex (18.2%, P < 0.001), prefrontal cortex (8%, P = 0.043), primary somatosensory cortex (17.7%, P = 0.002), and caudate putamen (14.5%, P = 0.02) compared to controls while a profound reduction of tyrosine hydroxylase (TH) immunostaining in the striatum was also observed. Alterations in [(3)H]ketanserin binding in the examined brain areas may represent the specific regions that mediate cognitive dysfunctions via the serotonin system. The downregulation of 5-HT(2A) receptor binding in this study also provides indirect evidence for plasticity in the serotonergic system in the rat brains. This study contributes to a better understanding of the critical roles of 5-HT(2A) receptors in treating neurodegenerative disorders and implicates 5-HT(2A) receptors as a novel therapeutic target in the treatment of PD.
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Affiliation(s)
- Yun Li
- Centre for Translational Neuroscience, School of Health Sciences, University of Wollongong, NSW, Australia
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247
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Filip M, Bader M. Overview on 5-HT receptors and their role in physiology and pathology of the central nervous system. Pharmacol Rep 2010; 61:761-77. [PMID: 19903999 DOI: 10.1016/s1734-1140(09)70132-x] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Revised: 09/21/2009] [Indexed: 12/19/2022]
Abstract
The present review gives an overview on the serotonin (5-hydroxytryptamine; 5-HT) system, its receptors and their relationship to central nervous system physiology and disorders. Additionally, we also introduce the recent knowledge about the 5-HT receptor ligands in preclinical research, clinical trials and as approved drugs.
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Affiliation(s)
- Małgorzata Filip
- Laboratory of Drug Addiction Pharmacology, Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, PL 31-343 Kraków, Poland.
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248
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Polymorphisms in GRIK4, HTR2A, and FKBP5 show interactive effects in predicting remission to antidepressant treatment. Neuropsychopharmacology 2010; 35:727-40. [PMID: 19924111 PMCID: PMC3055621 DOI: 10.1038/npp.2009.180] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Single-nucleotide polymorphisms (SNPs) in the FKBP5, GRIK4, and HTR2A genes have been shown to be associated with response to citalopram treatment in the STAR(*)D sample, but only associations with FKBP5 have so far been tested in the Munich Antidepressant Response Signature (MARS) project. Response and remission of depressive symptoms after 5 weeks of antidepressant treatment were tested against 82 GRIK4 and 37 HTR2A SNPs. Association analysis was conducted in about 300 depressed patients from the MARS project, 10% of whom had bipolar disorder. The most predictive SNPs from these two genes and rs1360780 in FKBP5 were then genotyped in a total of 387 German depressed in-patients to analyze potential additive and interactive effects of these variants. We could not replicate previous findings of the Sequenced Treatment Alternatives to Relieve Depression (STAR(*)D) study in our sample. Although not statistically significant, the effect for the best GRIK4 SNP of STAR(*)D (rs1954787, p=0.076, p(corrected)=0.98) seemed to be in the same direction. On the other hand, the nominally significant association with the top HTR2A SNPs of STAR(*)D (rs7997012, allelic, p=0.043, p(corrected)=0.62) was with the opposite risk allele. The GRIK4 SNP (rs12800734, genotypic, p=0.0019, p(corrected)=0.12) and the HTR2A SNP (rs17288723, genotypic, p=0.0011, p(corrected)=0.02), which showed the strongest association with remission in our sample, had not been reported previously. Associations across all genetic markers within the GRIK4 (genotypic, p=0.022) or HTR2A (genotypic, p=0.012) locus using the Fisher's product method (FPM) were also significant. In all 374 patients, the best predictive model included a main effect for GRIK4 rs12800734 and two significant interactions between GRIK4 rs12800734 and FKBP5 rs1360780, and GRIK4 rs12800734 and HTR2A rs17288723. This three SNP model explained 13.1% of the variance for remission after 5 weeks (p=0.00051 for the model). Analyzing a sub-sample of 194 patients, plasma ACTH (p=0.002) and cortisol (p=0.021) responses of rs12800734 GG (GRIK4) carriers, who also showed favorable treatment response, were significantly lower in the second combined dexamethasone (dex)/corticotrophin-releasing hormone (CRH) test before discharge compared with the other two genotype groups. Despite large differences in ethnicity and design compared with the STAR(*)D study, our results from the MARS study further support both independent and interactive involvement of GRIK4, HTR2A and FKBP5 in antidepressant treatment response.
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Richardson-Jones JW, Craige CP, Guiard BP, Stephen A, Metzger KL, Kung HF, Gardier AM, Dranovsky A, David DJ, Beck SG, Hen R, Leonardo ED. 5-HT1A autoreceptor levels determine vulnerability to stress and response to antidepressants. Neuron 2010; 65:40-52. [PMID: 20152112 PMCID: PMC2941196 DOI: 10.1016/j.neuron.2009.12.003] [Citation(s) in RCA: 318] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/13/2009] [Indexed: 12/28/2022]
Abstract
Most depressed patients don't respond to their first drug treatment, and the reasons for this treatment resistance remain enigmatic. Human studies implicate a polymorphism in the promoter of the serotonin-1A (5-HT(1A)) receptor gene in increased susceptibility to depression and decreased treatment response. Here we develop a new strategy to manipulate 5-HT(1A) autoreceptors in raphe nuclei without affecting 5-HT(1A) heteroreceptors, generating mice with higher (1A-High) or lower (1A-Low) autoreceptor levels. We show that this robustly affects raphe firing rates, but has no effect on either basal forebrain serotonin levels or conflict-anxiety measures. However, compared to 1A-Low mice, 1A-High mice show a blunted physiological response to acute stress, increased behavioral despair, and no behavioral response to antidepressant, modeling patients with the 5-HT(1A) risk allele. Furthermore, reducing 5-HT(1A) autoreceptor levels prior to antidepressant treatment is sufficient to convert nonresponders into responders. These results establish a causal relationship between 5-HT(1A) autoreceptor levels, resilience under stress, and response to antidepressants.
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Lowry CA, Hale MW. Serotonin and the Neurobiology of Anxious States. HANDBOOK OF BEHAVIORAL NEUROSCIENCE 2010. [DOI: 10.1016/s1569-7339(10)70091-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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