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Neural plasticity and proliferation in the generation of antidepressant effects: hippocampal implication. Neural Plast 2013; 2013:537265. [PMID: 23862076 PMCID: PMC3703717 DOI: 10.1155/2013/537265] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 05/01/2013] [Accepted: 05/08/2013] [Indexed: 12/15/2022] Open
Abstract
It is widely accepted that changes underlying depression and antidepressant-like effects involve not only alterations in the levels of neurotransmitters as monoamines and their receptors in the brain, but also structural and functional changes far beyond. During the last two decades, emerging theories are providing new explanations about the neurobiology of depression and the mechanism of action of antidepressant strategies based on cellular changes at the CNS level. The neurotrophic/plasticity hypothesis of depression, proposed more than a decade ago, is now supported by multiple basic and clinical studies focused on the role of intracellular-signalling cascades that govern neural proliferation and plasticity. Herein, we review the state-of-the-art of the changes in these signalling pathways which appear to underlie both depressive disorders and antidepressant actions. We will especially focus on the hippocampal cellularity and plasticity modulation by serotonin, trophic factors as brain-derived neurotrophic factor (BDNF), and vascular endothelial growth factor (VEGF) through intracellular signalling pathways—cAMP, Wnt/β-catenin, and mTOR. Connecting the classic monoaminergic hypothesis with proliferation/neuroplasticity-related evidence is an appealing and comprehensive attempt for improving our knowledge about the neurobiological events leading to depression and associated to antidepressant therapies.
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Xue R, Zhang YP, Jin ZL, Yuan L, He XH, Zhao N, Chen HX, Zhang LM, Fan SY, Zhong BH, Zhang YZ, Li YF. The discovery of 071031B, a novel serotonin and noradrenaline reuptake inhibitor. Neurosci Lett 2013; 544:68-73. [PMID: 23570736 DOI: 10.1016/j.neulet.2013.02.076] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 02/19/2013] [Accepted: 02/24/2013] [Indexed: 10/27/2022]
Abstract
Depression is a severe mood disorder with increasing morbidity and suicidality, while the current therapy is not satisfactory. Serotonin and noradrenaline reuptake inhibitors (SNRIs) have been reported to have higher efficacy and/or faster acting rate than commonly used antidepressants. The present study was designed to screen the potential SNRIs, using in vitro radioligand receptor binding assays and in vivo animal tests, and introduced the discovery of 071031B. In the tail suspension test and forced swimming test in mice, six compounds (071017S, 071026W, 071031A, 071031B, 080307A and 080307B) showed robust antidepressant activity, without stimulant effect on the locomotor activity or other side effects, and the minimal effective dose of 071017S, 071026W, 071031A and 071031B was less than that of duloxetine; in vitro binding tests indicated that 071031B had high affinity to both serotonin transporter and noradrenaline transporter with similar inhibitory rates to duloxetine at 1 and 100 nM; acute toxicity test indicated that the LD50 value of 071031B was similar to that of duloxetine. These findings demonstrated that this integrated system, combining high throughput screening technology and in vivo animal tests, is effective to screen potential monoamine reuptake inhibitors fast and accurately; 071031B is expected to be a novel serotonin and noradrenaline reuptake inhibitor for its robust antidepressant activity and transporter affinity.
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Affiliation(s)
- Rui Xue
- Department of New Drug Evaluation, Beijing Institute of Pharmacology and Toxicology, Beijing, PR China
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Abstract
A long-standing theory is that brain monoamine signalling is critically involved in the mechanisms of antidepressant drug treatment. Theories on the nature of these mechanisms commenced with ideas developed in the 1960s that the drugs act simply by increasing monoamine availability in the synapse. However, this thinking has advanced remarkably in the last decade to concepts which position that antidepressant drug action on monoamine signalling is just the starting point for a complex sequence of neuroadaptive molecular and cellular changes that bring about the therapeutic effect. These changes include activation of one or more programmes of gene expression that leads to the strengthening of synaptic efficacy and connectivity, and even switching neural networks into a more immature developmental state. It is thought that through this increase in plasticity, key neural circuits within the limbic system are more easily remodelled by incoming emotionally relevant stimuli. This article attempts to bring together previous and current knowledge of antidepressant drug action on monoamine signalling at molecular and cellular levels, and introduces current thinking that these changes interact with neuropsychological processes ultimately to elevate mood.
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Affiliation(s)
- Trevor Sharp
- University Department of Pharmacology, Mansfield Road, Oxford, OX1 3QT, UK.
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104
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Artigas F. Serotonin receptors involved in antidepressant effects. Pharmacol Ther 2013; 137:119-31. [DOI: 10.1016/j.pharmthera.2012.09.006] [Citation(s) in RCA: 184] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 09/14/2012] [Indexed: 12/19/2022]
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Abstract
Trazodone is a triazolopyridine derivative that belongs to the class of serotonin receptor antagonists and reuptake inhibitors (SARIs). The drug is approved and marketed in several countries worldwide for the treatment of major depressive disorder (MDD) in adult patients. In clinical studies, trazodone has demonstrated comparable antidepressant activity to other drug classes, including tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs) and serotonin-noradrenaline (norepinephrine) reuptake inhibitors (SNRIs). Moreover, the SARI action of trazodone may overcome the tolerability issues that are often associated with second-generation antidepressants such as SSRIs (i.e. insomnia, anxiety and sexual dysfunction). Recent focus has been placed on the development of a new prolonged-release once-a-day formulation of trazodone (TzCOAD), which may provide improved tolerability over the conventional immediate-release formulation of trazodone. Clinical studies have led to the recent approval in the USA of TzCOAD (as Oleptro™; Angelini Labopharm LLC, Princeton, NJ, USA), which may see resurgence of interest in the drug for the management of patients with MDD. Although trazodone is approved for the treatment of depression, evidence supports the use of low-dose trazodone as an off-label hypnotic for the treatment of sleep disorders in patients with MDD. The most common adverse effects reported with trazodone are drowsiness (somnolence/sedation), headache, dizziness and dry mouth. Other events reported, albeit with low incidence, include orthostatic hypotension (particularly in elderly patients or those with heart disease), minimal anticholinergic activity, corrected QT interval prolongation and torsade de pointes, cardiac arrhythmias, and rare occurrences of priapism and suicidal ideation. Overall, trazodone is an effective and well tolerated antidepressant (SARI) with an important role in the current treatment of MDD both as monotherapy and as part of a combination strategy. Trazodone is effective in controlling a wide range of symptoms of depression, while avoiding the negative effects on sleep seen with SSRI antidepressants. The recently approved prolonged-release formulation should provide further optimization of this antidepressant and may be useful for enabling an appropriate therapeutic dose to be administered with improved patient compliance.
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Affiliation(s)
- Andrea Fagiolini
- Division of Psychiatry, Department of Molecular Medicine, University of Siena School of Medicine, Viale Bracci 1, Siena, Italy.
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106
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Oba A, Nakagawasai O, Onogi H, Nemoto W, Yaoita F, Arai Y, Tan-No K, Tadano T. Chronic fluvoxamine treatment changes 5-HT(2A/2C) receptor-mediated behavior in olfactory bulbectomized mice. Life Sci 2012; 92:119-24. [PMID: 23159642 DOI: 10.1016/j.lfs.2012.11.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2012] [Revised: 10/18/2012] [Accepted: 11/05/2012] [Indexed: 11/25/2022]
Abstract
AIMS Olfactory bulbectomy (OBX) in rodents represents a valuable experimental model of depression. This study was designed to shed further light on the impact of putative serotonergic neuronal degeneration in OBX mice and to assess the effect of a widely used antidepressant on serotonergic related behavioral changes induced by OBX. MAIN METHODS Adult male ddY mice were subject to bilateral OBX or sham surgery. The serotonin (5-HT)(2A/2C) receptor agonist 2,5-dimethoxy-4-iodoamphetamine (DOI) enhanced a head-twitch response (HTR) in OBX mice. Effects of 5-HT(2A), 5-HT(2C) antagonists and fluvoxamine were observed in OBX mice following DOI administration. KEY FINDINGS The HTR elicited by the administration of DOI (0.5 mg/kg and 1 mg/kg, i.p.) was increased about twofold in OBX mice when compared with controls on the 14th day after the surgery. The injection of ketanserin (0.025 mg/kg, i.p.), a 5-HT(2A) receptor antagonist, inhibited the enhancement of the DOI-induced HTR after OBX. Likewise, the administration of SB 242084 (1 mg/kg, s.c.), a 5-HT(2C) receptor antagonist, also inhibited the DOI-induced HTR in OBX mice. Chronic but not acute treatment with the antidepressant fluvoxamine, a selective serotonin reuptake inhibitor (SSRI), suppressed the enhancement of DOI-induced HTR after OBX. SIGNIFICANCE These findings indicate that OBX, and the subsequent degeneration of neurons projecting from the olfactory bulb, caused a supersensitivity of 5-HT(2A/2C) receptors which may be involved in symptoms of depression.
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Affiliation(s)
- Akira Oba
- Department of Pharmacology, Tohoku Pharmaceutical University, Sendai 981-8558, Japan
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107
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Hughes CR, Tran L, Keele NB. 5-HT 2A Receptor Activation Normalizes Exaggerated Fear Behavior in p-Chlorophenylalanine (PCPA)-Treated Rats. JOURNAL OF BEHAVIORAL AND BRAIN SCIENCE 2012; 2:454-462. [PMID: 36910575 PMCID: PMC10003617 DOI: 10.4236/jbbs.2012.24053] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Deficits in serotonin (5-hydroxytryptamine, 5-HT) neurotransmission are implicated in abnormal emotional behaviors such as aggression, anxiety, and depression. However, the specific 5-HT receptor mechanisms involved are not well understood. The role of 5-HT2 receptors in fear potentiated startle, (FPS) was examined in rats chronically treated with p-chlorophenylalanine (PCPA) to reduce brain 5-HT. PCPA-treated rats show an enhanced magnitude of FPS. Systemic administration of the 5-HT2 receptor agonist (±)-2,5-Dimethoxy-4-iodoamphetamine hydrochloride (DOI) reduced FPS in both PCPA-treated and saline (SAL)-treated control animals, normalizing the exaggerated fear response in PCPA-treated rats. In both SAL- and PCPA-treated animals, the DOI-induced reduction of learned fear was reversed by the 5-HT2 antagonist ketanserin, but not by the 5-HT2B/2C antagonist SB 206553. Together, these findings suggest 5-HT2A receptors are critical regulators of learned fear, and that 5-HT2A receptors may be an important pharmacological target to normalize exaggerated learned fear resulting from chronic 5-HT-ergic disruption.
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Affiliation(s)
- Cathryn R Hughes
- Department of Psychology & Neuroscience, Baylor University, Waco, USA
| | - Lee Tran
- Department of Psychology & Neuroscience, Baylor University, Waco, USA.,Institute of Biomedical Studies, Baylor University, Waco, USA
| | - N Bradley Keele
- Department of Psychology & Neuroscience, Baylor University, Waco, USA.,Institute of Biomedical Studies, Baylor University, Waco, USA
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Adriaens AM, Polis IE, Vermeire ST, Waelbers T, Duchateau L, Sys SU, Van Dorpe S, Eersels JL, De Spiegeleer B, Peremans K. The influence of morphine on cerebral 5-HT2A availability in dogs: a SPECT study. J Nucl Med 2012; 53:1969-73. [PMID: 23090214 DOI: 10.2967/jnumed.112.103796] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED The opioid and serotonergic systems are closely involved in pain processing and mood disorders. The aim of this study was to assess the influence of systemic morphine on cerebral serotonin 2A receptor (5-HT(2A)) binding in dogs using SPECT with the 5-HT(2A) radioligand (123)I-5I-R91150. METHODS 5-HT(2A) binding was estimated with and without morphine pretreatment in 8 dogs. The 5-HT(2A) binding indices in the frontal, parietal, temporal, and occipital cortex and in the subcortical region were obtained by semiquantification. RESULTS A significantly decreased 5-HT(2A) binding index was found in the morphine group for the right (morphine, 1.41 ± 0.06; control, 1.52 ± 0.10) and left (morphine, 1.44 ± 0.08; control, 1.55 ± 0.11) frontal cortices, with P = 0.012 and P = 0.040, respectively. No significant differences were noted for the other regions. CONCLUSION Morphine decreased the frontocortical 5-HT(2A) availability, confirming an interaction between the 5-HTergic and the opioid systems. Whether this interaction is caused by decreased receptor density due to direct internalization or is the result of indirect actions, such as increased endogenous serotonin release, remains to be elucidated.
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Affiliation(s)
- Antita M Adriaens
- Medicine and Clinical Biology of Small Animals, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
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109
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Benyamina A, Naassila M, Bourin M. Potential role of cortical 5-HT(2A) receptors in the anxiolytic action of cyamemazine in benzodiazepine withdrawal. Psychiatry Res 2012; 198:307-12. [PMID: 22421069 DOI: 10.1016/j.psychres.2012.01.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Revised: 12/12/2011] [Accepted: 01/10/2012] [Indexed: 11/19/2022]
Abstract
The antipsychotic cyamemazine is a potent serotonin 5-HT(2A) receptor (5-HT(2AR)) antagonist. A positron emission tomography (PET) study in human patients showed that therapeutic doses of cyamemazine produced near saturation of 5-HT(2AR) occupancy in the frontal cortex, whereas dopamine D(2) occupancy remained below the level for motor side effects observed with typical antipsychotics. Recently, numerous studies have revealed the involvement of 5-HT(2AR) in the pathophysiology of anxiety and a double-blind, randomized clinical trial showed similar efficacy of cyamemazine and bromazepam in reducing the anxiety associated with benzodiazepine withdrawal. Therefore, we reviewed the above articles about 5-HT(2AR) and anxiety in order to understand better the anxiolytic mechanisms of cyamemazine in benzodiazepine withdrawal. The 5-HT(2AR) is the most abundant serotonin receptor subtype in the cortex. Non-pharmacological studies with antisense oligodeoxynucleotides and genetically modified mice clearly showed that cortical 5-HT(2AR) signaling positively modulates anxiety-like behavior. With a few exceptions, most other studies reviewed here further support this view. Therefore, the anxiolytic efficacy of cyamemazine in benzodiazepine withdrawal can be due to a 5-HT(2AR) antagonistic activity at the cortical level.
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Affiliation(s)
- Amine Benyamina
- Inserm U669, University Hospital Paul Brousse, Villejuif, France.
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110
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Fang CK, Chen HW, Chiang IT, Chen CC, Liao JF, Su TP, Tung CY, Uchitomi Y, Hwang JJ. Mirtazapine inhibits tumor growth via immune response and serotonergic system. PLoS One 2012; 7:e38886. [PMID: 22808019 PMCID: PMC3396612 DOI: 10.1371/journal.pone.0038886] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 05/14/2012] [Indexed: 02/06/2023] Open
Abstract
To study the tumor inhibition effect of mirtazapine, a drug for patients with depression, CT26/luc colon carcinoma-bearing animal model was used. BALB/c mice were randomly divided into six groups: two groups without tumors, i.e. wild-type (no drug) and drug (mirtazapine), and four groups with tumors, i.e. never (no drug), always (pre-drug, i.e. drug treatment before tumor inoculation and throughout the experiment), concurrent (simultaneously tumor inoculation and drug treatment throughout the experiment), and after (post-drug, i.e. drug treatment after tumor inoculation and throughout the experiment). The “psychiatric” conditions of mice were observed from the immobility time with tail suspension and spontaneous motor activity post tumor inoculation. Significant increase of serum interlukin-12 (sIL-12) and the inhibition of tumor growth were found in mirtazapine-treated mice (always, concurrent, and after) as compared with that of never. In addition, interferon-γ level and immunocompetent infiltrating CD4+/CD8+ T cells in the tumors of mirtazapine-treated, tumor-bearing mice were significantly higher as compared with that of never. Tumor necrosis factor-α (TNF-α) expressions, on the contrary, are decreased in the mirtazapine-treated, tumor-bearing mice as compared with that of never. Ex vivo autoradiography with [123I]ADAM, a radiopharmaceutical for serotonin transporter, also confirms the similar results. Notably, better survival rates and intervals were also found in mirtazapine-treated mice. These findings, however, were not observed in the immunodeficient mice. Our results suggest that tumor growth inhibition by mirtazapine in CT26/luc colon carcinoma-bearing mice may be due to the alteration of the tumor microenvironment, which involves the activation of the immune response and the recovery of serotonin level.
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Affiliation(s)
- Chun-Kai Fang
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan
- Department of Psychiatry and Suicide Prevention Center, Mackay Memorial Hospital, Taipei, Taiwan
| | - Hong-Wen Chen
- Department of Radiation Oncology and Hospice Palliative Care Center, Mackay Memorial Hospital, Taipei, Taiwan
| | - I-Tsang Chiang
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan
| | | | - Jyh-Fei Liao
- Institute of Pharmacology, National Yang-Ming University, Taipei, Taiwan
| | - Ton-Ping Su
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Chieh-Yin Tung
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Yosuke Uchitomi
- Department of Neuropsychiatry, School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama-shi, Japan
| | - Jeng-Jong Hwang
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan
- * E-mail:
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Pilar-Cuéllar F, Vidal R, Pazos A. Subchronic treatment with fluoxetine and ketanserin increases hippocampal brain-derived neurotrophic factor, β-catenin and antidepressant-like effects. Br J Pharmacol 2012; 165:1046-57. [PMID: 21627639 DOI: 10.1111/j.1476-5381.2011.01516.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND AND PURPOSE 5-HT(2A) receptor antagonists improve antidepressant responses when added to 5-HT-selective reuptake inhibitors (SSRIs) or tricyclic antidepressants. Here, we have studied the involvement of neuroplasticity pathways and/or the 5-hydroxytryptaminergic system in the antidepressant-like effect of this combined treatment, given subchronically. EXPERIMENTAL APPROACH Expression of brain-derived neurotrophic factor (BDNF) and its receptor (TrkB), 5-bromo-2'-deoxyuridine (BrdU) incorporation, and β-catenin protein expression in different cellular fractions, as well as 5-HT(1A) receptor function were measured in the hippocampus of rats treated with fluoxetine, ketanserin and fluoxetine + ketanserin for 7 days, followed by a forced swimming test (FST) to analyse antidepressant efficacy. KEY RESULTS mRNA for BDNF was increased in the CA3 field and dentate gyrus of the hippocampus by combined treatment with fluoxetine + ketanserin. Expression of β-catenin was increased in total hippocampal homogenate and in the membrane fraction, but unchanged in the nuclear fraction after combined treatment with fluoxetine + ketanserin. These effects were paralleled by a decreased immobility time in the FST. There were no changes in BrdU incorporation, TrkB expression and 5-HT(1A) receptor function in any of the groups studied. CONCLUSIONS AND IMPLICATIONS The antidepressant-like effect induced by subchronic co-treatment with a SSRI and a 5-HT(2A) receptor antagonist may mainly be because of modifications in hippocampal neuroplasticity (BDNF and membrane-associated β-catenin), without a significant role for other mechanisms involved in chronic antidepressant response, such as hippocampal neuroproliferation or 5-HT(1A) receptor desensitization in the dorsal raphe nucleus.
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Affiliation(s)
- F Pilar-Cuéllar
- Departamento de Fisiología y Farmacología, Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), Universidad de Cantabria-CSIC-IDICAN, Santander, Cantabria, Spain
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112
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Canal CE, Morgan D. Head-twitch response in rodents induced by the hallucinogen 2,5-dimethoxy-4-iodoamphetamine: a comprehensive history, a re-evaluation of mechanisms, and its utility as a model. Drug Test Anal 2012; 4:556-76. [PMID: 22517680 DOI: 10.1002/dta.1333] [Citation(s) in RCA: 144] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 01/09/2012] [Accepted: 01/10/2012] [Indexed: 11/06/2022]
Abstract
Two primary animal models persist for assessing hallucinogenic potential of novel compounds and for examining the pharmacological and neurobiological substrates underlying the actions of classical hallucinogens, the two-lever drug discrimination procedure and the drug-induced head-twitch response (HTR) in rodents. The substituted amphetamine hallucinogen, serotonin 2 (5-HT(2) ) receptor agonist, 2,5-dimethoxy-4-iodoamphetamine (DOI) has emerged as the most popular pharmacological tool used in HTR studies of hallucinogens. Synthesizing classic, recent, and relatively overlooked findings, addressing ostensibly conflicting observations, and considering contemporary theories in receptor and behavioural pharmacology, this review provides an up-to-date and comprehensive synopsis of DOI and the HTR model, from neural mechanisms to utility for understanding psychiatric diseases. Also presented is support for the argument that, although both the two-lever drug discrimination and the HTR models in rodents are useful for uncovering receptors, interacting proteins, intracellular signalling pathways, and neurochemical processes affected by DOI and related classical hallucinogens, results from both models suggest they are not reporting hallucinogenic experiences in animals.
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Affiliation(s)
- Clint E Canal
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA.
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113
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Hasegawa S, Fikre-Merid M, Diksic M. 5-HT2A receptor antagonist M100907 reduces serotonin synthesis: an autoradiographic study. Brain Res Bull 2012; 87:44-9. [PMID: 22056993 PMCID: PMC3653840 DOI: 10.1016/j.brainresbull.2011.10.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 10/19/2011] [Indexed: 11/16/2022]
Abstract
The effects of the administration of the serotonin (5-HT)(2A) antagonist, M100907, on 5-HT synthesis rates, were evaluated using the α-[(14)C]methyl-l-tryptophan (α-MTrp) autoradiographic method. In the treatment study, M100907 (10mg/kg) was injected intraperitoneally 30 min before the α-MTrp injection (30 μCi over 2 min). A single dose of M100907 caused a significant decrease in the synthesis in the anterior olfactory nucleus, accumbens nucleus, frontal cortex, sensory-motor cortex, cingulate cortex, medial caudate-putamen, dorsal thalamus, substantia nigra, inferior collicus, raphe magnus nucleus, superior olive, and raphe pallidus nucleus. These data suggest that the terminal 5-HT(2A) receptors are involved in the regulation of 5-HT synthesis in the entire brain. Further, 5-HT synthesis is likely regulated by the 5-HT(2A) antagonistic property of M100907 in the cortices, anterior olfactory nucleus, caudate putamen, and nucleus accumbens.
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Affiliation(s)
| | - Maraki Fikre-Merid
- Cone Neurosurgical Research Laboratory, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4
| | - Mirko Diksic
- Cone Neurosurgical Research Laboratory, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4
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114
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Homberg JR. Serotonin and decision making processes. Neurosci Biobehav Rev 2012; 36:218-36. [DOI: 10.1016/j.neubiorev.2011.06.001] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2011] [Revised: 05/27/2011] [Accepted: 06/02/2011] [Indexed: 10/18/2022]
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115
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Chen ML, Tsai TC, Wang LK, Lin YY, Tsai YM, Lee MC, Tsai FM. Risperidone modulates the cytokine and chemokine release of dendritic cells and induces TNF-α-directed cell apoptosis in neutrophils. Int Immunopharmacol 2011; 12:197-204. [PMID: 22154580 DOI: 10.1016/j.intimp.2011.11.011] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Revised: 11/07/2011] [Accepted: 11/23/2011] [Indexed: 10/14/2022]
Abstract
Antipsychotic drugs (APDs) that bind mainly to the dopamine D2 receptor or the type II 5-HT receptor have been used to ease the symptoms of schizophrenia. Several studies have reported that APDs can also regulate the immune response. Dendritic cells (DCs) are the major antigen-presenting cells in the immune system. DCs can release 5-HT and dopamine to modulate T-cell activation and differentiation. In this study, we use the monocyte-derived DCs to investigate the drug effects of typical APD (haloperidol) and atypical APD (risperidone) on DCs in vitro. Our studies revealed that only risperidone but not haloperidol affected the cytokine and chemokine production of mature DCs. Risperidone increased the production of IL-10 and MDC as well as the proinflammatory cytokines, such as IL-6, IL-8, and TNF-α, but decreased the production of IP-10 and IL-12. Furthermore, the exposure of DCs to risperidone led to lower IFN-γ production by T-cells. The results suggested that risperidone can modulate the DCs' immune function by inhibiting the potent Th1 cytokines and increasing the potent Th2 cytokines. In addition, the production of TNF-α by risperidone-treated mature DCs will induce the death of neutrophils.
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Affiliation(s)
- Mao-Liang Chen
- Department of Research, Buddhist Tzu Chi General Hospital, Taipei Branch, New Taipei City, Taiwan
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116
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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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117
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Polter AM, Li X. Glycogen Synthase Kinase-3 is an Intermediate Modulator of Serotonin Neurotransmission. Front Mol Neurosci 2011; 4:31. [PMID: 22028682 PMCID: PMC3199786 DOI: 10.3389/fnmol.2011.00031] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 09/28/2011] [Indexed: 01/22/2023] Open
Abstract
Serotonin is a neurotransmitter with broad functions in brain development, neuronal activity, and behaviors; and serotonin is the prominent drug target in several major neuropsychiatric diseases. The multiple actions of serotonin are mediated by diverse serotonin receptor subtypes and associated signaling pathways. However, the key signaling components that mediate specific function of serotonin neurotransmission have not been fully identified. This review will provide evidence from biochemical, pharmacological, and animal behavioral studies showing that serotonin regulates the activation states of brain glycogen synthase kinase-3 (GSK3) via type 1 and type 2 serotonin receptors. In return, GSK3 directly interacts with serotonin receptors in a highly selective manner, with a prominent effect on modulating serotonin 1B receptor activity. Therefore, GSK3 acts as an intermediate modulator in the serotonin neurotransmission system, and balanced GSK3 activity is essential for serotonin-regulated brain function and behaviors. Particularly important, several classes of serotonin-modulating drugs, such as antidepressants and atypical antipsychotics, regulate GSK3 by inhibiting its activity in brain, which reinforces the importance of GSK3 as a potential therapeutic target in neuropsychiatric diseases associated with abnormal serotonin function.
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Affiliation(s)
- Abigail M Polter
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham Birmingham, AL, USA
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Seo HJ, Park EJ, Kim MJ, Kang SY, Lee SH, Kim HJ, Lee KN, Jung ME, Lee M, Kim MS, Son EJ, Park WK, Kim J, Lee J. Design and synthesis of novel arylpiperazine derivatives containing the imidazole core targeting 5-HT(2A) receptor and 5-HT transporter. J Med Chem 2011; 54:6305-18. [PMID: 21823597 DOI: 10.1021/jm200682b] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Serotonin antagonist reuptake inhibitor (SARI) drugs that block both 5-HT(2) receptors and the serotonin transporters have been developed. The human 5-HT(2A/2C) receptor has been implicated in several neurological conditions, and potent selective 5-HT(2A/2C) ligands may have therapeutic potential for treatment of CNS diseases such as depression. An imidazole moiety usually provides good pharmacokinetic properties as a drug substance, and thus considerable efforts have been devoted to develop imidazole derivatives into drug candidates. The imidazole series of compounds was evaluated against 5-HT(2A/2C) and serotonin reuptake inhibition. A few of the compounds in the series showed promising IC(50) values and antidepressant-like effect in in vivo forced swimming test (FST). On the basis of these results, further lead optimization studies resulted in identifying promising compounds potentially for therapeutic use.
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Affiliation(s)
- Hee Jeong Seo
- Research Center, Green Cross Corporation, 303 Bojeong-dong, Giheung-gu, Yongin 446-770, Korea
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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: 50] [Impact Index Per Article: 3.8] [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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120
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Altamura AC, Lietti L, Dobrea C, Benatti B, Arici C, Dell'Osso B. Mood stabilizers for patients with bipolar disorder: the state of the art. Expert Rev Neurother 2011; 11:85-99. [PMID: 21158558 DOI: 10.1586/ern.10.181] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Bipolar disorder (BD) is a prevalent and disabling condition, often comorbid with other medical and psychiatric conditions and frequently misdiagnosed. International treatment guidelines for BD recommend the use of mood stabilizers - either in monotherapy or in association - as the gold standard in both acute and long-term therapy. Commonly used in the clinical practice of BD, mood stabilizers have represented an evolving field over the last few years. The concept of stabilization, in fact, has been stressed as the ultimate objective of the treatment of BD, given the chronic and recurrent nature of the illness, which accounts for its significant levels of impairment and disability. To date, different compounds are included within the broad class of mood stabilizers, with lithium, anticonvulsants and, more recently, atypical antipsychotics being the most representative agents. This article is aimed at providing an updated review of the available literature in relation to the role of mood stabilizers in BD, with particular emphasis on their mechanism of action, main clinical aspects and specific use in the different phases of BD treatment, according to the most recently published international treatment guidelines.
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Affiliation(s)
- A Carlo Altamura
- Department of Neurological Sciences, University of Milan, Milan, Italy
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121
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Dougherty JP, Aloyo VJ. Pharmacological and behavioral characterization of the 5-HT2A receptor in C57BL/6N mice. Psychopharmacology (Berl) 2011; 215:581-93. [PMID: 21340474 DOI: 10.1007/s00213-011-2207-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 01/27/2011] [Indexed: 11/30/2022]
Abstract
RATIONALE The serotonin (5-HT) 2A receptor is implicated in numerous psychiatric disorders, making it an important, clinically relevant target. Despite the availability of transgenic mouse lines, the native mouse 5-HT(2A) receptor is not well-characterized. OBJECTIVES The goals of the current study were to determine 5-HT(2A) and 5-HT(2C) receptor densities in mouse cortex, establish a pharmacological profile of the mouse 5-HT(2A) receptor, and determine the effects of chronic drug treatment on 5-HT(2A) receptor density and 5-HT(2A) receptor-mediated behavior. METHODS Receptor densities were determined in cortex and frontal cortex via saturation binding assays using [(3)H]ketanserin or [(3)H]mesulergine. A pharmacological profile was established by displacing [(3)H]ketanserin binding with several ligands. Chronic treatment with 5-HT(2A/2C) receptor agonist, 2,5-dimethoxy-4-iodoamphetamine (DOI), 5-HT(2A) receptor antagonist, MDL 11939, or vehicle was followed by 5-HT(2A) receptor density determination. Head twitch responses (HTRs) were counted on select days. RESULTS Mice had high 5-HT(2A), but low 5-HT(2C) receptor densities. Ligand binding affinities for mouse 5-HT(2A) receptors correlated with rat, but not rabbit or human, affinities. Chronically DOI-treated mice displayed reduced HTRs and 5-HT(2A) receptor density compared to saline-treated mice. Receptor density was unchanged following chronic treatment with MDL 11939. CONCLUSIONS The current study provides some basic information about mouse 5-HT(2A) and 5-HT(2C) receptors and provides comparisons to rats, rabbits, and humans. The current chronic agonist treatment study demonstrated an important similarity between the 5-HT(2A) receptor in mice, rats, and rabbits, while antagonist treatment revealed an interesting difference from previous studies in rabbits.
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Affiliation(s)
- John P Dougherty
- Drexel University College of Medicine, Philadelphia, PA 19102, USA.
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Abstract
Serotonin (5-HT)3 receptors are the only ligand-gated ion channel of the 5-HT receptors family. They are present both in the peripheral and central nervous system and are localized in several areas involved in mood regulation (e.g., hippocampus or prefrontal cortex). Moreover, they are involved in regulation of neurotransmitter systems implicated in the pathophysiology of major depression (e.g., dopamine or GABA). Clinical and preclinical studies have suggested that 5-HT3 receptors may be a relevant target in the treatment of affective disorders. 5-HT3 receptor agonists seem to counteract the effects of antidepressants in non-clinical models, whereas 5-HT3 receptor antagonists, such as ondansetron, present antidepressant-like activities. In addition, several antidepressants, such as mirtazapine, also target 5-HT3 receptors. In this review, we will report major advances in the research of 5-HT3 receptor's roles in neuropsychiatric disorders, with special emphasis on mood and anxiety disorders.
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Carr GV, Lucki I. The role of serotonin receptor subtypes in treating depression: a review of animal studies. Psychopharmacology (Berl) 2011; 213:265-87. [PMID: 21107537 PMCID: PMC3374933 DOI: 10.1007/s00213-010-2097-z] [Citation(s) in RCA: 171] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Accepted: 11/04/2010] [Indexed: 01/22/2023]
Abstract
RATIONALE Serotonin reuptake inhibitors (SSRIs) are effective in treating depression. Given the existence of different families and subtypes of 5-HT receptors, multiple 5-HT receptors may be involved in the antidepressant-like behavioral effects of SSRIs. OBJECTIVE Behavioral pharmacology studies investigating the role of 5-HT receptor subtypes in producing or blocking the effects of SSRIs were reviewed. RESULTS Few animal behavior tests were available to support the original development of SSRIs. Since their development, a number of behavioral tests and models of depression have been developed that are sensitive to the effects of SSRIs, as well as to other types of antidepressant treatments. The rationale for the development and use of these tests is reviewed. Behavioral effects similar to those of SSRIs (antidepressant-like) have been produced by agonists at 5-HT(1A), 5-HT(1B), 5-HT(2C), 5-HT(4), and 5-HT(6) receptors. Also, antagonists at 5-HT(2A), 5-HT(2C), 5-HT(3), 5-HT(6), and 5-HT(7) receptors have been reported to produce antidepressant-like responses. Although it seems paradoxical that both agonists and antagonists at particular 5-HT receptors can produce antidepressant-like effects, they probably involve diverse neurochemical mechanisms. The behavioral effects of SSRIs and other antidepressants may also be augmented when 5-HT receptor agonists or antagonists are given in combination. CONCLUSIONS The involvement of 5-HT receptors in the antidepressant-like effects of SSRIs is complex and involves the orchestration of stimulation and blockade at different 5-HT receptor subtypes. Individual 5-HT receptors provide opportunities for the development of a newer generation of antidepressants that may be more beneficial and effective than SSRIs.
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Gould GG, Hensler JG, Burke TF, Benno RH, Onaivi ES, Daws LC. Density and function of central serotonin (5-HT) transporters, 5-HT1A and 5-HT2A receptors, and effects of their targeting on BTBR T+tf/J mouse social behavior. J Neurochem 2011; 116:291-303. [PMID: 21070242 PMCID: PMC3012263 DOI: 10.1111/j.1471-4159.2010.07104.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BTBR mice are potentially useful tools for autism research because their behavior parallels core social interaction impairments and restricted-repetitive behaviors. Altered regulation of central serotonin (5-HT) neurotransmission may underlie such behavioral deficits. To test this, we compared 5-HT transporter (SERT), 5-HT(1A) and 5-HT(2A) receptor densities among BTBR and C57 strains. Autoradiographic [(3) H] cyanoimipramine (1 nM) binding to SERT was 20-30% lower throughout the adult BTBR brain as compared to C57BL/10J mice. In hippocampal membrane homogenates, [(3) H] citalopram maximal binding (B(max) ) to SERT was 95 ± 13 fmol/mg protein in BTBR and 171 ± 20 fmol/mg protein in C57BL/6J mice, and the BTBR dissociation constant (K(D) ) was 2.0 ± 0.3 nM versus 1.1 ± 0.2 in C57BL/6J mice. Hippocampal 5-HT(1A) and 5-HT(2A) receptor binding was similar among strains. However, 8-OH-DPAT-stimulated [(35) S] GTPγS binding in the BTBR hippocampal CA(1) region was 28% higher, indicating elevated 5-HT(1A) capacity to activate G-proteins. In BTBR mice, the SERT blocker, fluoxetine (10 mg/kg) and the 5-HT(1A) receptor partial-agonist, buspirone (2 mg/kg) enhanced social interactions. The D(2) /5-HT(2) receptor antagonist, risperidone (0.1 mg/kg) reduced marble burying, but failed to improve sociability. Overall, altered SERT and/or 5-HT(1A) functionality in hippocampus could contribute to the relatively low sociability of BTBR mice.
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MESH Headings
- Animals
- Brain/drug effects
- Brain/metabolism
- Brain/physiology
- Buspirone/pharmacology
- Fluoxetine/pharmacology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Inbred Strains
- Protein Binding/physiology
- Protein Transport
- Receptor, Serotonin, 5-HT1A/metabolism
- Receptor, Serotonin, 5-HT1A/physiology
- Receptor, Serotonin, 5-HT2A/metabolism
- Receptor, Serotonin, 5-HT2A/physiology
- Serotonin Plasma Membrane Transport Proteins/metabolism
- Serotonin Plasma Membrane Transport Proteins/physiology
- Social Behavior
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Affiliation(s)
- Georgianna G Gould
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229-3900, USA.
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125
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Iijima M, Ito A, Kurosu S, Chaki S. Pharmacological characterization of repeated corticosterone injection-induced depression model in rats. Brain Res 2010; 1359:75-80. [DOI: 10.1016/j.brainres.2010.08.078] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Revised: 08/23/2010] [Accepted: 08/24/2010] [Indexed: 11/29/2022]
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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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Bambico FR, Cassano T, Dominguez-Lopez S, Katz N, Walker CD, Piomelli D, Gobbi G. Genetic deletion of fatty acid amide hydrolase alters emotional behavior and serotonergic transmission in the dorsal raphe, prefrontal cortex, and hippocampus. Neuropsychopharmacology 2010; 35:2083-100. [PMID: 20571484 PMCID: PMC3055302 DOI: 10.1038/npp.2010.80] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Pharmacological blockade of the anandamide-degrading enzyme, fatty acid amide hydrolase (FAAH), produces CB(1) receptor (CB(1)R)-mediated analgesic, anxiolytic-like and antidepressant-like effects in murids. Using behavioral and electrophysiological approaches, we have characterized the emotional phenotype and serotonergic (5-HT) activity of mice lacking the FAAH gene in comparison to their wild type counterparts, and their response to a challenge of the CB(1)R antagonist, rimonabant. FAAH null-mutant (FAAH(-/-)) mice exhibited reduced immobility in the forced swim and tail suspension tests, predictive of antidepressant activity, which was attenuated by rimonabant. FAAH(-/-) mice showed an increase in the duration of open arm visits in the elevated plus maze, and a decrease in thigmotaxis and an increase in exploratory rearing displayed in the open field, indicating anxiolytic-like effects that were reversed by rimonabant. Rimonabant also prolonged the initiation of feeding in the novelty-suppressed feeding test. Electrophysiological recordings revealed a marked 34.68% increase in dorsal raphe 5-HT neural firing that was reversed by rimonabant in a subset of neurons exhibiting high firing rates (33.15% mean decrease). The response of the prefrontocortical pyramidal cells to the 5-HT(2A/2C) agonist (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane ((+/-)-DOI) revealed desensitized 5-HT(2A/2C) receptors, likely linked to the observed anxiolytic-like behaviors. The hippocampal pyramidal response to the 5-HT(1A) antagonist, WAY-100635, indicates enhanced tonus on the hippocampal 5-HT(1A) heteroreceptors, a hallmark of antidepressant-like action. Together, these results suggest that FAAH genetic deletion enhances anxiolytic-like and antidepressant-like effects, paralleled by altered 5-HT transmission and postsynaptic 5-HT(1A) and 5-HT(2A/2C) receptor function.
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Affiliation(s)
| | - Tommaso Cassano
- Department of Biomedical Sciences, University of Foggia, Foggia, Italy
| | - Sergio Dominguez-Lopez
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montréal, QC, Canada
| | - Noam Katz
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montréal, QC, Canada
| | - Claire Dominique Walker
- Neuroscience and Mood, Anxiety and Impulsivity Disorders-Related Research Division, Douglas Mental Health University Institute, Montréal, QC, Canada
| | - Daniele Piomelli
- Department of Pharmacology and Center for Drug Discovery, University of California, Irvine, CA, USA
| | - Gabriella Gobbi
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montréal, QC, Canada,Department of Psychiatry Research and Training Building, McGill University, Neurobiological Psychiatry Unit, 1033 Pine Avenue West, Montréal, Québec, Canada H3A 1A1, Tel: +1 514 398 1290, Fax: +1 514 398 4866, E-mail:
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A novel 5-HT2A receptor antagonist exhibits antidepressant-like effects in a battery of rodent behavioural assays: Approaching early-onset antidepressants. Pharmacol Biochem Behav 2010; 94:363-73. [DOI: 10.1016/j.pbb.2009.09.018] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2009] [Revised: 09/10/2009] [Accepted: 09/24/2009] [Indexed: 11/19/2022]
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130
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Electrophysiology of Serotonin Receptors. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/s1569-7339(10)70077-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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131
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132
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Harrison-Read PE. Antimanic potency of typical neuroleptic drugs and affinity for dopamine D2 and serotonin 5-HT2A receptors--a new analysis of data from the archives and implications for improved antimanic treatments. J Psychopharmacol 2009; 23:899-907. [PMID: 18635692 DOI: 10.1177/0269881108094349] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Datasets of antimanic potency ratings and receptor-binding affinities [inhibition constants (K(i))] at dopamine D2 and serotonin 5-HT2A brain receptors were accessed from published literature for a large series (n = 24) of typical neuroleptic drugs, many of which are now obsolete and unobtainable. There was a strong positive association between antimanic potency and affinity for D2 receptors, in support of a 'dopamine-blockade hypothesis' of antimanic drug action. Taking the series of neuroleptics as a whole, there was no association between antimanic potency and affinity for 5-HT2A receptors. Despite this, within a subsample of typical neuroleptics with low affinity for D2 receptors resembling new generation atypical antipsychotics, a positive association between antimanic potency and affinity for 5-HT2A receptors emerged. This suggests that blockade of brain 5-HT2A receptors plays at least a subsidiary role in the antimanic effects of some typical neuroleptics. Other considerations also suggest that combining drugs to achieve high affinity for and blockade of both dopamine D2 receptors and serotonin 5-HT2A receptors, possibly with additional direct or indirect stimulation of postsynaptic 5-HT1A receptors, might maximize antimanic efficacy.
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Affiliation(s)
- P E Harrison-Read
- Department of Psychiatry, Royal Free Hospital, Pond Street, London, UK.
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133
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Abstract
Multifunctional drugs are those with more than one therapeutic mechanism. Trazodone is a multifunctional drug with dose-dependent pharmacologic actions. That is, it has hypnotic actions at low doses due to blockade of 5-HT2Areceptors, as well as H1histamine receptors and α1 adrenergic receptors. Higher doses recruit the blockade of the serotonin transporter (SERT) and turn trazodone into an antidepressant. Although trazodone has traditionally been used as a low dose hypnotic, a new controlled release formulation that has the potential to improve the tolerability of high doses may provide an opportunity to revisit this multifunctional drug as an antidepressant as well.
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134
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Long AB, Kuhn CM, Platt ML. Serotonin shapes risky decision making in monkeys. Soc Cogn Affect Neurosci 2009; 4:346-56. [PMID: 19553236 DOI: 10.1093/scan/nsp020] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Some people love taking risks, while others avoid gambles at all costs. The neural mechanisms underlying individual variation in preference for risky or certain outcomes, however, remain poorly understood. Although behavioral pathologies associated with compulsive gambling, addiction and other psychiatric disorders implicate deficient serotonin signaling in pathological decision making, there is little experimental evidence demonstrating a link between serotonin and risky decision making, in part due to the lack of a good animal model. We used dietary rapid tryptophan depletion (RTD) to acutely lower brain serotonin in three macaques performing a simple gambling task for fluid rewards. To confirm the efficacy of RTD experiments, we measured total plasma tryptophan using high-performance liquid chromatography (HPLC) with electrochemical detection. Reducing brain serotonin synthesis decreased preference for the safe option in a gambling task. Moreover, lowering brain serotonin function significantly decreased the premium required for monkeys to switch their preference to the risky option, suggesting that diminished serotonin signaling enhances the relative subjective value of the risky option. These results implicate serotonin in risk-sensitive decision making and, further, suggest pharmacological therapies for treating pathological risk preferences in disorders such as problem gambling and addiction.
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Affiliation(s)
- Arwen B Long
- Department of Neurobiology, Duke University, Box 3209, Durham, NC 27710, USA.
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135
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Landolt HP, Wehrle R. Antagonism of serotonergic 5-HT2A/2C receptors: mutual improvement of sleep, cognition and mood? Eur J Neurosci 2009; 29:1795-809. [PMID: 19473234 DOI: 10.1111/j.1460-9568.2009.06718.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Serotonin [5-hydroxytryptamine (5-HT)] and 5-HT receptors are involved in sleep and in waking functions such as cognition and mood. Animal and human studies support a particular role for the 5-HT(2A) receptor in sleep, which has led to renewed interest in this receptor subtype as a target for the development of novel pharmacological agents to treat insomnia. Focusing primarily on findings in healthy human volunteers, a review of the available data suggests that antagonistic interaction with 5-HT(2A) receptors (and possibly also 5-HT(2C) receptors) prolongs the duration of slow wave sleep and enhances low-frequency (< 7 Hz) activity in the sleep electroencephalogram (EEG), a widely accepted marker of sleep intensity. Despite certain differences, the changes in sleep and the sleep EEG appear to be remarkably similar to those of physiologically more intense sleep after sleep deprivation. It is currently unclear whether these changes in sleep are associated with improved vigilance, cognition and mood during wakefulness. While drug-induced interaction with sleep must be interpreted cautiously, too few studies are available to provide a clear answer to this question. Moreover, functional relationships between sleep and waking functions may differ between healthy controls and patients with sleep disorders. A multimodal approach investigating subjective and objective aspects of sleep and wakefulness provides a promising research avenue for shedding light on the complex relationships among 5-HT(2A/2C) receptor-mediated effects on sleep, the sleep EEG, cognition and mood in health and various diseases associated with disturbed sleep and waking functions.
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Affiliation(s)
- H-P Landolt
- Institute of Pharmacology and Toxicology, University of Zürich, Zürich, Switzerland.
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136
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Rajkumar R, Pandey DK, Mahesh R, Radha R. 1-(m-Chlorophenyl)piperazine induces depressogenic-like behaviour in rodents by stimulating the neuronal 5-HT2A receptors: Proposal of a modified rodent antidepressant assay. Eur J Pharmacol 2009; 608:32-41. [DOI: 10.1016/j.ejphar.2009.02.041] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Revised: 02/11/2009] [Accepted: 02/12/2009] [Indexed: 11/30/2022]
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137
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Dhir A, Kulkarni S. Risperidone, an atypical antipsychotic enhances the antidepressant-like effect of venlafaxine or fluoxetine: Possible involvement of alpha-2 adrenergic receptors. Neurosci Lett 2008; 445:83-8. [DOI: 10.1016/j.neulet.2008.08.074] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2008] [Revised: 08/07/2008] [Accepted: 08/27/2008] [Indexed: 10/21/2022]
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138
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Ardayfio PA, Benvenga MJ, Chaney SF, Love PL, Catlow J, Swanson SP, Marek GJ. The 5-hydroxytryptamine2A receptor antagonist R-(+)-alpha-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl-4-piperidinemethanol (M100907) attenuates impulsivity after both drug-induced disruption (dizocilpine) and enhancement (antidepressant drugs) of differential-reinforcement-of-low-rate 72-s behavior in the rat. J Pharmacol Exp Ther 2008; 327:891-7. [PMID: 18772320 DOI: 10.1124/jpet.108.143370] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous work has suggested that N-methyl-d-aspartate (NMDA) receptor antagonism and 5-hydroxytryptamine (5-HT)(2A) receptor blockade may enhance and attenuate, respectively, certain types of impulsivity mediated by corticothalamostriatal circuits. More specifically, past demonstrations of synergistic "antidepressant-like" effects of a 5-HT(2A) receptor antagonist and fluoxetine on differential-reinforcement-of-low-rate (DRL) 72-s schedule of operant reinforcement may speak to the role of 5-HT(2A) receptor blockade with respect to response inhibition as an important prefrontal cortical executive function relating to motor impulsivity. To examine the dynamic range over which 5-HT(2A) receptor blockade may exert effects on impulsivity, [R-(+)-alpha-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl-4-piperidinemethanol] (M100907) was examined both alone and in combination with the psychotomimetic NMDA receptor antagonist dizocilpine [e.g., (-)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate; MK-801] and two different antidepressants, the tricyclic antidepressant desmethylimipramine (DMI) and the monoamine oxidase inhibitor tranylcypromine in rats performing under a DRL 72-s schedule. MK-801 increased the response rate, decreased the number of reinforcers obtained, and exerted a leftward shift in the inter-response time (IRT) distribution as expected. A dose of M100907 that exerted minimal effect on DRL behavior by itself attenuated the psychotomimetic effects of MK-801. Extending previous M100907-fluoxetine observations, addition of a minimally active dose of M100907 to low doses of DMI and tranylcypromine enhanced the antidepressant-like effect of the antidepressants. Therefore, it may be that a tonic excitation of 5-HT(2A) receptors modulates impulsivity and function of corticothalamostriatal circuits over an extensive dynamic range.
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Affiliation(s)
- Paul A Ardayfio
- Lilly Research Laboratories, Lilly Corporate Center, Eli Lilly and Company, Indianapolis, Indiana, USA
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139
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A randomized, double-blind, and placebo-controlled trial of quetiapine augmentation of fluoxetine in major depressive disorder. Int Clin Psychopharmacol 2008; 23:269-75. [PMID: 18703936 DOI: 10.1097/yic.0b013e328301a74c] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The objective of this study was to investigate whether quetiapine, when compared with placebo, can speed the onset of action and improve the quality of response to fluoxetine treatment in patients suffering from major depressive disorder. A total of 114 patients with major depressive disorder were enrolled in an 8-week treatment study. Patients were initiated on a course of fluoxetine treatment and randomized to quetiapine or placebo. Quetiapine was flexibly dosed starting at 25 mg to a maximum of 100 mg daily. Mixed-effects regression showed that quetiapine plus fluoxetine did not achieve 50% reduction in the Montgomery-Asberg Depression Rating Scale score or improvement in Hamilton Anxiety Scale, Clinical Global Improvement (CGI)-Severity, and CGI-Improvement scores sooner than the fluoxetine plus placebo group; however both groups improved in all scores over time. Mixed-effects linear regression of insomnia scores showed that the quetiapine plus fluoxetine group improved significantly more rapidly compared with the fluoxetine plus placebo group. The study indicates that quetiapine plus fluoxetine did not achieve a reduction in the Montgomery-Asberg Depression Rating Scale score or improvement in Hamilton Anxiety Scale or CGI scores from baseline sooner than the fluoxetine plus placebo group. The combination of quetiapine and fluoxetine, however, improved sleep over fluoxetine alone over the first few weeks of treatment.
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140
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Abstract
Obsessive–compulsive disorder (OCD) is a psychiatric disorder consisting of obsessions and compulsions. Over the past two decades, it has been suggested that OCD might be related to the functioning of brain serotonin systems, mainly because of the antiobsessional efficacy of selective serotonin-reuptake inhibitors (SSRIs). Although the efficacy of SSRIs suggests a role of the serotonergic system in OCD, the exact function of serotonin is still unclear. Is the serotonergic system implicated in the pathophysiology of OCD, or is it implicated in the treatment effect in OCD? Do SSRIs compensate for a fundamental abnormality of the serotonergic system, or do SSRIs modulate an intact serotonergic system to compensate for another neurotransmitter mechanism? This review summarizes evidence supporting a role for the serotonin transporter and serotonin receptor subtypes in the pathophysiology and treatment of OCD.
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Affiliation(s)
- Addy van Dijk
- University of Amsterdam, Department of Psychiatry, Academic Medical Center (AMC), Amsterdam, The Netherlands
| | - Andre Klompmakers
- University of Amsterdam, Department of Psychiatry, Academic Medical Center (AMC), Amsterdam, The Netherlands
| | - Damiaan Denys
- University of Amsterdam, PA.2–179, PO Box 75867, 1070 AW Amsterdam, The Netherlands
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141
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Evaluation of serotonin-2A receptor occupancy with 123I-5-I-R91150 and single-photon emission tomography before and after low-dose pipamperone administration in the canine brain. Nucl Med Commun 2008; 29:724-9. [DOI: 10.1097/mnm.0b013e3282fdc989] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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142
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Serotonin evokes endocannabinoid release and retrogradely suppresses excitatory synapses. J Neurosci 2008; 28:6508-15. [PMID: 18562622 DOI: 10.1523/jneurosci.0678-08.2008] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
5-HT(2)-type serotonin receptors (5-HT(2)Rs) are widely expressed throughout the brain and mediate many of the modulatory effects of serotonin. It has been thought that postsynaptic 5-HT(2)Rs act primarily by depolarizing neurons and thereby increasing their excitability. However, it is also known that 5-HT(2)Rs are coupled to G(q/11)-type G-proteins and that some other types of G(q/11)-coupled receptors can regulate synapses by evoking endocannabinoid release and activating presynaptic cannabinoid-type 1 receptors (CB(1)Rs). Here, we examine whether activation of 5-HT(2)Rs can regulate synapses through such a mechanism by studying excitatory synapses onto cells in the inferior olive (IO). These cells express 5-HT(2)Rs on their soma and dendrites, and the IO receives extensive serotonergic input. We find that the excitatory synaptic inputs onto IO cells are strongly suppressed by serotonin receptor agonists as well as release of endogenous serotonin. Both 5-HT(2)Rs and 5-HT(1B)Rs contribute to this modulation by decreasing the probability of glutamate release from presynaptic boutons. The suppression by 5-HT(2)Rs is of particular interest because it is prevented by CB(1)R antagonists, and 5-HT(2)Rs are thought to be located only postsynaptically on IO cells. Our results indicate that serotonin activates 5-HT(2)Rs on IO neurons, thereby releasing endocannabinoids that act retrogradely to suppress glutamate release by activating presynaptic CB(1)Rs. These findings establish a link between serotonin signaling and endocannabinoid signaling. Based on the extensive distribution of 5-HT(2)Rs and CB(1)Rs, it seems likely that this mechanism could mediate many of the actions of 5-HT(2)Rs throughout the brain.
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143
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Marek GJ. Regulation of rat cortical 5-hydroxytryptamine2A receptor-mediated electrophysiological responses by repeated daily treatment with electroconvulsive shock or imipramine. Eur Neuropsychopharmacol 2008; 18:498-507. [PMID: 18294819 PMCID: PMC2453314 DOI: 10.1016/j.euroneuro.2008.01.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Revised: 12/16/2007] [Accepted: 01/09/2008] [Indexed: 10/22/2022]
Abstract
Down-regulation of 5-hydroxytryptamine(2A) (5-HT(2A)) receptors has been a consistent effect induced by most antidepressant drugs. In contrast, electroconvulsive shock (ECS) up-regulates the number of 5-HT(2A) receptor binding sites. However, the effects of antidepressants on 5-HT(2A) receptor-mediated responses on identified cells of the cerebral cortex have not been examined. The purpose of the present study was to compare the effects of the tricyclic antidepressant imipramine and ECS on 5-HT(2A) receptor-mediated electrophysiological responses involving glutamatergic and GABAergic neurotransmission in the rat medial prefrontal cortex (mPFC) and piriform cortex, respectively. The electrophysiological effects of activating 5-HT(2A) receptors were consistent with 5-HT(2A) receptor binding regulation for imipramine and ECS except for the mPFC where chronic ECS decreased the potency of 5-HT at a 5-HT(2A) receptor-mediated response. These findings are consistent with the general hypothesis that chronic antidepressant treatments shift the balance of serotonergic neurotransmission towards inhibitory effects in the cortex.
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Affiliation(s)
- Gerard J Marek
- Discovery Biology, Eli Lilly Corporate Center, Mail Drop 0510, Indianapolis, IN 46285, United States.
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144
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Jha S, Rajendran R, Fernandes KA, Vaidya VA. 5-HT2A/2C receptor blockade regulates progenitor cell proliferation in the adult rat hippocampus. Neurosci Lett 2008; 441:210-4. [PMID: 18603367 DOI: 10.1016/j.neulet.2008.06.028] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2007] [Revised: 06/05/2008] [Accepted: 06/11/2008] [Indexed: 11/15/2022]
Abstract
Adult hippocampal neurogenesis is reported to be a target of antidepressants, drugs of abuse and animal models of depression, suggesting a role for this form of structural plasticity in psychopathology. Serotonergic neurotransmission, which is implicated in several psychiatric diseases, has been reported to regulate adult hippocampal neurogenesis. Amongst the serotonergic receptors, the serotonin2A/2C (5-HT2A/2C) receptors play an important role in the actions of antidepressants and the effects of hallucinogenic drugs of abuse. We have used the mitotic marker 5'-bromo-2-deoxyuridine to address the effects of the 5-HT2A/2C receptors on the proliferation of adult hippocampal progenitors following acute or chronic treatment with the hallucinogenic partial agonists, (+/-)-2,5-dimethoxy-4-iodoamphetamine (DOI) and lysergic acid diethylamide (LSD) and the antagonist, Ketanserin. Acute, and chronic, DOI and LSD treatments induced a strong behavioral activation, but did not alter adult hippocampal progenitor proliferation. In striking contrast, Ketanserin treatment resulted in a biphasic regulation with a significant decline (22%) in progenitor proliferation following a single treatment, and a robust increase (46%) observed following chronic administration. These results indicate that hallucinogenic drugs that primarily target the 5-HT2A/2C receptors, in contrast to other drugs of abuse, may not alter adult hippocampal neurogenesis. In addition, our results that enhanced adult hippocampal progenitor proliferation results from a sustained blockade of the 5-HT2A/2C receptors suggest that the 5-HT2A/2C receptors may be an important target for the neurogenic effects of antidepressant treatment.
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Affiliation(s)
- Shanker Jha
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai 400005, India
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145
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Marek GJ. Cortical 5-hydroxytryptamine2A-receptor mediated excitatory synaptic currents in the rat following repeated daily fluoxetine administration. Neurosci Lett 2008; 438:312-6. [PMID: 18486339 DOI: 10.1016/j.neulet.2008.04.068] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2008] [Revised: 03/16/2008] [Accepted: 04/11/2008] [Indexed: 11/16/2022]
Abstract
Down-regulation of 5-hydroxytryptamine(2A) (5-HT(2A)) receptors has been a consistent effect induced by most antidepressant drugs. The evidence for down-regulation of 5-HT(2A) receptor binding following subchronic treatment with fluoxetine and other selective serotonin reuptake inhibitors (SSRIs) is mixed. The question of 5-HT(2A) receptor sensitivity during chronic administration of antidepressants is important since activation of 5-HT(2A) receptors is associated with impulsivity. Continued activation of 5-HT(2A) receptors may functionally oppose activation of other non-5-HT(2A) receptors in the prefrontal cortex associated with the clinical efficacy of SSRI treatment. Therefore, the effects of repeated daily administration of fluoxetine (10 mg/kg, i.p. x 3 weeks) on pharmacologically characterized electrophysiological response mediated by 5-HT(2A) receptor activation, 5-HT-induced excitatory postsynaptic currents (EPSCs), in rat prefrontal cortical slices was examined. The concentration-response curve for 5-HT-induced EPSCs was unchanged following subchronic fluoxetine treatment. This subchronic fluoxetine treatment failed to modify electrophysiological responses to AMPA in layer V pyramidal cells as well. These findings would be consistent with the hypothesis that blockade of 5-HT(2A) receptors may enhance the effects of SSRIs or serotonin/norepinephrine reuptake inhibitors (SNRIs).
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Affiliation(s)
- Gerard J Marek
- Discovery Biology, Eli Lilly and Company, Lilly Corporate Center, Mail Drop 0510, Indianapolis, IN 46285 USA.
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146
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Takahashi H, Kamata M, Yoshida K, Higuchi H, Ishigooka J. Augmentation with olanzapine in TCA-refractory depression with melancholic features: a consecutive case series. Hum Psychopharmacol 2008; 23:217-20. [PMID: 18172909 DOI: 10.1002/hup.914] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Using an 8-week, open label study design, we report the effect of augmentation strategy with olanzapine in hospitalized depressive patients with melancholic features who had insufficient response to a tricyclic antidepressant (TCA), amitriptyline. Subjects were hospitalized patients meeting the criteria of DSM-IV major depressive disorder with melancholic features who had been suffering from residual symptoms after treatment of amitriptyline. After study entry, olanzapine was added to amitriptyline and the dose was adjusted according to patients' clinical condition. Data were analyzed using an intent-to-treat methodology, with last observation carried forward. Paired t-test was adopted to assess the data from baseline to endpoint. Of 26 patients who enrolled in this study, 23 patients completed the trial and 3 patients dropped out. The mean dose of olanzapine was 6.5 (SD = 2.4) mg/day. The mean score of Montgomery-Asberg Depression Rating Scale (MADRS) was significantly decreased from 33.6 (SD = 3.5) to 20.8 (SD = 9.1) during this study (37.9% from baseline) (p < 0.001). Ten patients (38.5%) were considered as responders (50% or greater reduction in MADRS scores from baseline). These results suggest that augmentation with olanzapine in TCAs-resistant melancholia may be effective and well tolerated. We cannot draw any conclusion with certainty from the open-label, uncontrolled clinical trial. Double blind, controlled trial is needed to confirm this preliminary finding.
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Affiliation(s)
- Hitoshi Takahashi
- Department of Psychiatry, Tokyo Women Medical University, Tokyo, Japan.
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147
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Goddard AW, Shekhar A, Whiteman AF, McDougle CJ. Serotoninergic mechanisms in the treatment of obsessive–compulsive disorder. Drug Discov Today 2008; 13:325-32. [DOI: 10.1016/j.drudis.2007.12.009] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Revised: 12/19/2007] [Accepted: 12/20/2007] [Indexed: 11/29/2022]
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148
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Obsessive-compulsive symptoms in a randomized, double-blind study with olanzapine or risperidone in young patients with early psychosis. J Clin Psychopharmacol 2008; 28:214-8. [PMID: 18344733 DOI: 10.1097/jcp.0b013e318166f520] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND The prevalence of obsessive-compulsive symptoms (OCS) in patients with schizophrenia is relatively high. Antipsychotics have been found to influence OCS. OBJECTIVE To determine whether induction or severity of OCS differs during treatment with olanzapine or risperidone in young patients with early psychosis. METHODS One hundred twenty-two patients with a Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition diagnosis of schizophrenia, schizoaffective disorder, or schizophreniform disorder were randomized in a double-blind design to groups of 6 weeks' treatment with olanzapine (n = 59) or risperidone (n = 63), with a mean dose of 11.3 mg olanzapine and 3.0 mg risperidone at 6 weeks. Primary outcome measures were the mean baseline-to-endpoint change in total score on the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). RESULTS Treatment with olanzapine was associated with greater decreases in Y-BOCS total score than treatment with risperidone in total group (N = 122: -2.2 vs -0.3, z = -2.651, P < 0.01), in patients with baseline Y-BOCS total score greater than 0 (n = 58: -5.1 vs -0.4, z = -2.717, P < 0.01), and in patients with baseline Y-BOCS total score greater than 10 (n = 29: -7.1 vs -0.6, z = -2.138, P = 0.032). CONCLUSIONS In this randomized, 6-week, double-blind trial, we found a significant and clinically relevant difference in decrease in Y-BOCS scores favoring olanzapine compared with risperidone.
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149
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Kang RH, Choi MJ, Paik JW, Hahn SW, Lee MS. Effect of serotonin receptor 2A gene polymorphism on mirtazapine response in major depression. Int J Psychiatry Med 2008; 37:315-29. [PMID: 18314859 DOI: 10.2190/pm.37.3.h] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The 5-HTR2A gene is a candidate gene for influencing the clinical response to treatment with antidepressants. The purpose of this study was to determine the relationship between the -1438A/G polymorphism of the 5-HTR2A gene and the response to mirtazapine in a Korean population with major depressive disorder. Mirtazapine was administered for eight weeks to the 101 patients who completed the study, during which we evaluated the clinical outcome using repeated-measures ANCOVA. A main effect of genotype or an effect of genotype-time interactions on the decrease in HAMD score during the eight-week follow-up was not found, which suggests that the 5-HTR2A -1438A/G polymorphism does not affect the clinical outcome to mirtazapine administration. However, significant effects of genotype and allele carriers on the decrease in the sleep score over the eight weeks were found (genotype: F = 4.093, p = 0.017; allele: F = 4.371, p = 0.037), whereas no effect of genotype-time interactions on the decrease in the HAMD score over the eight-week follow-up was found. These observations suggest that the -1438A/G polymorphism on the sleep improvement at each time period revealed significant differences in the sleep scores after two weeks of mirtazapine administration. The sleep scores were lower for carriers of the A+ allele than of the A- allele after two weeks of mirtazapine administration (p = 0.041), which means that the -1438GG genotype is associated with less improvement in sleep, and suggests that the effect of mirtazapine on improving the sleep quality differs with the 5-HTR2A -1438A/G polymorphism within two weeks of mirtazapine treatment. In conclusion, although the -1438A/G polymorphism affects the sleep improvement resulting from the administration of mirtazapine to Korean patients with major depressive disorder, our results do not support the hypothesis that this polymorphism of the 5-HTR2A gene is involved in the therapeutic response to mirtazapine.
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150
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Kitamura Y, Fujitani Y, Kitagawa K, Miyazaki T, Sagara H, Kawasaki H, Shibata K, Sendo T, Gomita Y. Effects of Imipramine and Bupropion on the Duration of Immobility of ACTH-Treated Rats in the Forced Swim Test: Involvement of the Expression of 5-HT 2A Receptor mRNA. Biol Pharm Bull 2008; 31:246-9. [DOI: 10.1248/bpb.31.246] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Yoshihisa Kitamura
- Department of Pharmaceutical Care and Health Sciences, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
- Department of Hospital Pharmacy, Okayama University Medical School
| | - Yoshika Fujitani
- Department of Hospital Pharmacy, Okayama University Medical School
| | - Kouhei Kitagawa
- Department of Pharmaceutical Care and Health Sciences, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
- Department of Hospital Pharmacy, Okayama University Medical School
| | | | - Hidenori Sagara
- Department of Hospital Pharmacy, Okayama University Medical School
| | - Hiromu Kawasaki
- Department of Pharmaceutical Sciences, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University
| | - Kazuhiko Shibata
- Department of Hospital Pharmacy, Okayama University Medical School
| | - Toshiaki Sendo
- Department of Hospital Pharmacy, Okayama University Medical School
| | - Yutaka Gomita
- Department of Hospital Pharmacy, Okayama University Medical School
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