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Belmer A, Patkar OL, Pitman KM, Bartlett SE. Serotonergic Neuroplasticity in Alcohol Addiction. Brain Plast 2016; 1:177-206. [PMID: 29765841 PMCID: PMC5928559 DOI: 10.3233/bpl-150022] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Alcohol addiction is a debilitating disorder producing maladaptive changes in the brain, leading drinkers to become more sensitive to stress and anxiety. These changes are key factors contributing to alcohol craving and maintaining a persistent vulnerability to relapse. Serotonin (5-Hydroxytryptamine, 5-HT) is a monoamine neurotransmitter widely expressed in the central nervous system where it plays an important role in the regulation of mood. The serotonin system has been extensively implicated in the regulation of stress and anxiety, as well as the reinforcing properties of all of the major classes of drugs of abuse, including alcohol. Dysregulation within the 5-HT system has been postulated to underlie the negative mood states associated with alcohol use disorders. This review will describe the serotonergic (5-HTergic) neuroplastic changes observed in animal models throughout the alcohol addiction cycle, from prenatal to adulthood exposure. The first section will focus on alcohol-induced 5-HTergic neuroadaptations in offspring prenatally exposed to alcohol and the consequences on the regulation of stress/anxiety. The second section will compare alterations in 5-HT signalling induced by acute or chronic alcohol exposure during adulthood and following alcohol withdrawal, highlighting the impact on the regulation of stress/anxiety signalling pathways. The third section will outline 5-HTergic neuroadaptations observed in various genetically-selected ethanol preferring rat lines. Finally, we will discuss the pharmacological manipulation of the 5-HTergic system on ethanol- and anxiety/stress-related behaviours demonstrated by clinical trials, with an emphasis on current and potential treatments.
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Affiliation(s)
- Arnauld Belmer
- Translational Research Institute, Queensland University of Technology, Brisbane, Australia.,Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia
| | - Omkar L Patkar
- Translational Research Institute, Queensland University of Technology, Brisbane, Australia.,Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia
| | - Kim M Pitman
- Translational Research Institute, Queensland University of Technology, Brisbane, Australia.,Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia
| | - Selena E Bartlett
- Translational Research Institute, Queensland University of Technology, Brisbane, Australia.,Institute of Health and Biomedical Innovation (IHBI), Queensland University of Technology, Brisbane, Australia
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2
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Buchborn T, Schröder H, Dieterich DC, Grecksch G, Höllt V. Tolerance to LSD and DOB induced shaking behaviour: differential adaptations of frontocortical 5-HT(2A) and glutamate receptor binding sites. Behav Brain Res 2015; 281:62-8. [PMID: 25513973 DOI: 10.1016/j.bbr.2014.12.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Revised: 12/04/2014] [Accepted: 12/06/2014] [Indexed: 12/20/2022]
Abstract
Serotonergic hallucinogens, such as lysergic acid diethylamide (LSD) and dimethoxy-bromoamphetamine (DOB), provoke stereotype-like shaking behaviour in rodents, which is hypothesised to engage frontocortical glutamate receptor activation secondary to serotonin2A (5-HT2A) related glutamate release. Challenging this hypothesis, we here investigate whether tolerance to LSD and DOB correlates with frontocortical adaptations of 5-HT2A and/or overall-glutamate binding sites. LSD and DOB (0.025 and 0.25 mg/kg, i.p.) induce a ketanserin-sensitive (0.5 mg/kg, i.p., 30-min pretreatment) increase in shaking behaviour (including head twitches and wet dog shakes), which with repeated application (7× in 4 ds) is undermined by tolerance. Tolerance to DOB, as indexed by DOB-sensitive [(3)H]spiroperidol and DOB induced [(35)S]GTP-gamma-S binding, is accompanied by a frontocortical decrease in 5-HT2A binding sites and 5-HT2 signalling, respectively; glutamate-sensitive [(3)H]glutamate binding sites, in contrast, remain unchanged. As to LSD, 5-HT2 signalling and 5-HT2A binding, respectively, are not or only marginally affected, yet [(3)H]glutamate binding is significantly decreased. Correlation analysis interrelates tolerance to DOB to the reduced 5-HT2A (r=.80) as well as the unchanged [(3)H]glutamate binding sites (r=.84); tolerance to LSD, as opposed, shares variance with the reduction in [(3)H]glutamate binding sites only (r=.86). Given that DOB and LSD both induce tolerance, one correlating with 5-HT2A, the other with glutamate receptor adaptations, it might be inferred that tolerance can arise at either level. That is, if a hallucinogen (like LSD in our study) fails to induce 5-HT2A (down-)regulation, glutamate receptors (activated postsynaptic to 5-HT2A related glutamate release) might instead adapt and thus prevent further overstimulation of the cortex.
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Affiliation(s)
- Tobias Buchborn
- Institute of Pharmacology and Toxicology, Otto-von-Guericke University, 39120 Magdeburg, Germany.
| | - Helmut Schröder
- Institute of Pharmacology and Toxicology, Otto-von-Guericke University, 39120 Magdeburg, Germany.
| | - Daniela C Dieterich
- Institute of Pharmacology and Toxicology, Otto-von-Guericke University, 39120 Magdeburg, Germany; Leibniz Institute for Neurobiology, Magdeburg, Germany; Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany.
| | - Gisela Grecksch
- Institute of Pharmacology and Toxicology, Otto-von-Guericke University, 39120 Magdeburg, Germany.
| | - Volker Höllt
- Institute of Pharmacology and Toxicology, Otto-von-Guericke University, 39120 Magdeburg, Germany.
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3
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Miyaji K, Kato M, Ohtani N, Ohta M. Experimental Verification of the Effects on Normal Domestic Cats by Feeding Prescription Diet for Decreasing Stress. J APPL ANIM WELF SCI 2015; 18:355-62. [DOI: 10.1080/10888705.2015.1005301] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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4
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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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Bi-directional modulation of bed nucleus of stria terminalis neurons by 5-HT: molecular expression and functional properties of excitatory 5-HT receptor subtypes. Neuroscience 2009; 164:1776-93. [PMID: 19778589 DOI: 10.1016/j.neuroscience.2009.09.028] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Revised: 09/05/2009] [Accepted: 09/16/2009] [Indexed: 01/28/2023]
Abstract
Activation of neurons in the anterolateral bed nucleus of the stria terminalis (BNST(ALG)) plays an important role in mediating the behavioral response to stressful and anxiogenic stimuli. Application of 5-HT elicits complex postsynaptic responses in BNST(ALG) neurons, which includes (1) membrane hyperpolarization (5-HT(Hyp)), (2) hyperpolarization followed by depolarization (5-HT(Hyp-Dep)), (3) depolarization (5-HT(Dep)) or (4) no response (5-HT(NR)). We have shown that the inhibitory response is mediated by activation of postsynaptic 5-HT(1A) receptors. Here, we used a combination of in vitro whole-cell patch-clamp recording and single cell reverse transcriptase polymerase chain reaction (RT-PCR) to determine the pharmacological properties and molecular profile of 5-HT receptor subtypes mediating the excitatory response to 5-HT in BNST(ALG) neurons. We show that the depolarizing component of both the 5-HT(Hyp/Dep) and the 5-HT(Dep) response was mediated by activation of 5-HT(2A), 5-HT(2C) and/or 5-HT(7) receptors. Single cell RT-PCR data revealed that 5-HT(7) receptors (46%) and 5-HT(1A) receptors (41%) are the most prevalent receptor subtypes expressed in BNST(ALG) neurons. Moreover, 5-HT receptor subtypes are differentially expressed in type I-III BNST(ALG) neurons. Hence, 5-HT(2C) receptors are almost exclusively expressed by type III neurons, whereas 5-HT(7) receptors are expressed by type I and II neurons, but not type III neurons. Conversely, 5-HT(2A) receptors are found predominantly in type II neurons. Finally, bi-directional modulation of individual neurons occurs only in type I and II neurons. Significantly the distribution of 5-HT receptor subtypes in BNST(ALG) neurons predicted the observed expression pattern of 5-HT responses determined pharmacologically. Together, these results suggest that 5-HT can differentially modulate the excitability of type I-III neurons, and further suggest that bi-directional modulation of BNST(ALG) neurons occurs primarily through an interplay between 5-HT(1A) and 5-HT(7) receptors. Hence, modulation of 5-HT(7) receptor activity in the BNST(ALG) may offer a novel avenue for the design of anxiolytic medications.
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Hanley NR, Van de Kar LD. Serotonin and the neuroendocrine regulation of the hypothalamic--pituitary-adrenal axis in health and disease. VITAMINS AND HORMONES 2003; 66:189-255. [PMID: 12852256 DOI: 10.1016/s0083-6729(03)01006-9] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Serotonin (5-hydroxytryptamine, 5-HT)-containing neurons in the midbrain directly innervate corticotropin-releasing hormone (CRH)-containing cells located in paraventricular nucleus of the hypothalamus. Serotonergic inputs into the paraventricular nucleus mediate the release of CRH, leading to the release of adrenocorticotropin, which triggers glucocorticoid secretion from the adrenal cortex. 5-HT1A and 5-HT2A receptors are the main receptors mediating the serotonergic stimulation of the hypothalamic-pituitary-adrenal axis. In turn, both CRH and glucocorticoids have multiple and complex effects on the serotonergic neurons. Therefore, these two systems are interwoven and communicate closely. The intimate relationship between serotonin and the hypothalamic-pituitary-adrenal axis is of great importance in normal physiology such as circadian rhythm and stress, as well as pathophysiological disorders such as depression, anxiety, eating disorders, and chronic fatigue.
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Affiliation(s)
- N R Hanley
- Department of Pharmacology, Center for Serotonin Disorders Research, Loyola University of Chicago, Stritch School of Medicine, Maywood, Illinois 60153, USA
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7
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Van Oekelen D, Luyten WHML, Leysen JE. 5-HT2A and 5-HT2C receptors and their atypical regulation properties. Life Sci 2003; 72:2429-49. [PMID: 12650852 DOI: 10.1016/s0024-3205(03)00141-3] [Citation(s) in RCA: 148] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The 5-HT(2A) and 5-HT(2C) receptors belong to the G-protein-coupled receptor (GPCR) superfamily. GPCRs transduce extracellular signals to the interior of cells through their interaction with G-proteins. The 5-HT(2A) and 5-HT(2C) receptors mediate effects of a large variety of compounds affecting depression, schizophrenia, anxiety, hallucinations, dysthymia, sleep patterns, feeding behaviour and neuro-endocrine functions. Binding of such compounds to either 5-HT(2) receptor subtype induces processes that regulate receptor sensitivity. In contrast to most other receptors, chronic blockade of 5-HT(2A) and 5-HT(2C) receptors leads not to an up- but to a (paradoxical) down-regulation. This review deals with published data involving such non-classical regulation of 5-HT(2A) and 5-HT(2C) receptors obtained from in vivo and in vitro studies. The underlying regulatory processes of the agonist-induced regulation of 5-HT(2A) and 5-HT(2C) receptors, commonly thought to be desensitisation and resensitisation, are discussed. The atypical down-regulation of both 5-HT(2) receptor subtypes by antidepressants, antipsychotics and 5-HT(2) antagonists is reviewed. The possible mechanisms of this paradoxical down-regulation are discussed, and a new hypothesis on possible heterologous regulation of 5-HT(2A) receptors is proposed.
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Affiliation(s)
- Dirk Van Oekelen
- Johnson and Johnson Pharmaceutical, p/a Janssen Pharmaceutica, Turnhoutseweg 30, B-2340 Beerse, Belgium
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8
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Cyr M, Charbonneau C, Morissette M, Rochford J, Barden N, Di Paolo T. Central 5-hydroxytryptamine-2A receptor expression in transgenic mice bearing a glucocorticoid receptor antisense. Neuroendocrinology 2001; 73:37-45. [PMID: 11174015 DOI: 10.1159/000054618] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Transgenic mice bearing a transgene coding for a glucocorticoid receptor antisense mRNA that partially blocks glucocorticoid receptor expression were used to investigate the long-term effect of hypothalamic-pituitary-adrenal dysfunction on brain 5-hydroxytryptamine-2A (5-HT2A) receptor expression. The brain 5-HT2A receptor mRNA levels in transgenic mice were measured by in situ hybridization and compared to those in control mice. We also studied the effect of a 3-week treatment with fluoxetine on brain 5-HT2A receptor expression in the transgenic mice. No difference in 5-HT2A mRNA levels was observed between transgenic and control mice in cortical or striatal regions, and fluoxetine treatment was without effect. No difference in hypothalamic 5-HT2A mRNA levels was observed between transgenic and control mice, while fluoxetine treatment increased these levels in both transgenic as well as in the hypothalamic ventromedial and paraventricular nuclei of control mice. 5-HT2A receptor mRNA levels were similar in hippocampal CA1 and CA2 subregions of control and transgenic, but were lower in the CA3 and CA4 subregions of transgenic mice. Fluoxetine had no effect on 5-HT2A mRNA levels of transgenic mice but reduced control mouse 5-HT2A receptor mRNA levels in the CA3 subregion. These results suggest that impaired glucocorticoid receptor function can affect hippocampal 5-HT2A receptor expression in transgenic mice and that this is not corrected by fluoxetine treatment.
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MESH Headings
- Animals
- Cerebral Cortex/metabolism
- DNA, Antisense
- Depression/metabolism
- Female
- Fluoxetine/pharmacology
- Gene Expression/drug effects
- Gene Expression/physiology
- Hippocampus/metabolism
- In Situ Hybridization
- Male
- Mice
- Mice, Inbred C3H
- Mice, Inbred C57BL
- Mice, Transgenic
- Organ Culture Techniques
- RNA, Messenger/analysis
- Receptor, Serotonin, 5-HT2A
- Receptors, Glucocorticoid/genetics
- Receptors, Serotonin/genetics
- Receptors, Serotonin/metabolism
- Serotonin/metabolism
- Selective Serotonin Reuptake Inhibitors/pharmacology
- Species Specificity
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Affiliation(s)
- M Cyr
- Oncology and Molecular Endocrinology Research Center, CHUQ, Pavillon CHUL, Laval University, Sainte-Foy, Quebec, Canada
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9
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Abstract
There is evidence for stressor- and brain region-specific selectivity in serotonergic transmission responses to aversive stimuli. The aim of the present review is to provide an overview of the effects of different acute and repeated/chronic stressors on serotonin (5-HT) release and reuptake, extracellular 5-HT levels, and 5-HT pre- and postsynaptic receptors in areas tightly linked to the control of fear and anxiety, namely the dorsal and median raphe nuclei, the frontal cortex, the amygdala and the hippocampus. In addition, our knowledge of the impacts of corticoids on serotonergic systems in these brain areas is also briefly provided to examine whether the hypothalamo-pituitary-adrenal axis may play a role in stress-induced alterations in 5-HT neurotransmission. Taken together, the data presented reinforce the hypothesis that stress affects such a transmission, partly through the actions of corticoids. However, we are still left with unanswered, albeit crucial questions. First, the question of the specificity of the serotonergic responses to stress, with regard to the site of action and the nature of the stressor still remains open due to the heterogeneity of the results obtained so far. This could indicate that environmental factors, other than the stressor itself, may have enduring consequences on 5-HT sensitivity to stress. Second, the question regarding the role of stress-elicited changes in 5-HT transmission within coping processes finds in most cases no clearcut answer. In keeping with human symptomatology, the need to consider the environment (including the early one) and the genetic status when assessing the effects of stress on 5-HT neurotransmission is underlined. Such a consideration could help to answer the questions raised.
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Affiliation(s)
- F Chaouloff
- NeuroGénétique and Stress, INSERM U471, Institut F. Magendie, Bordeaux, France.
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10
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Farisse J, Héry F, Barden N, Héry M, Boulenguez P. Central 5-HT(1) and 5-HT(2) binding sites in transgenic mice with reduced glucocorticoid receptor number. Brain Res 2000; 862:145-53. [PMID: 10799679 DOI: 10.1016/s0006-8993(00)02104-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Transgenic mice bearing a transgene coding for a glucocorticoid receptor antisense mRNA, which partially blocks glucocorticoid receptor expression, were used in order to clarify the role of glucocorticoid receptors in the regulation of 5-HT(1A), 5-HT(1nonA) and 5-HT(2) binding sites labelled by quantitative autoradiography in the frontal and prefrontal cortex, striatum, hypothalamus, amygdala and raphe nuclei. We found that 1 nM [3H]8-hydroxy-2-[di-N-propylamino]tetralin ([3H]8-OH-DPAT) binding to 5-HT(1A) sites was decreased in strata oriens (-15.1+/-3.5%) and radiatum-lacunosum-moleculare (-13.3+/-4.3%) of the hippocampal CA(3) area, and 2 nM [3H]5-hydroxytryptamine binding to 5-HT(1nonA) sites in the presence of 100 nM 8-OH-DPAT and mesulergine was decreased in the dorsal subiculum (-17.8+/-6.9%). By contrast, 5-HT(2) sites labelled by 0.5 nM of (+/-)-1-(2, 5-dimethoxy-4-[125I]iodophenyl)-2-aminopropane was increased in the dorsal subiculum (+35.2+/-11.5%) and CA(2) area (+29.2+/-11.3%). The observed differences in binding to 5-HT(1) and 5-HT(2) sites were all located in areas of the hippocampus that contain both gluco- and mineralo-corticoid receptors, and no difference was observed in anatomical structures which contain only glucocorticoid receptors. Therefore, it seems that the important factor for the regulation of these 5-HT receptors is the interaction between gluco- and mineralo-corticoid receptors rather than the absolute density of glucocorticoid receptors. These results suggest that some of the alterations of the serotonergic neurotransmission observed in depressed patients might be secondary to an altered glucocorticoid receptor function.
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MESH Headings
- 8-Hydroxy-2-(di-n-propylamino)tetralin/pharmacology
- Amygdala/chemistry
- Amygdala/metabolism
- Animals
- Autoradiography
- Binding Sites
- Brain Chemistry/physiology
- Corpus Striatum/chemistry
- Corpus Striatum/metabolism
- Down-Regulation/genetics
- Hippocampus/chemistry
- Hippocampus/metabolism
- Mice
- Mice, Inbred Strains
- Mice, Transgenic
- Paraventricular Hypothalamic Nucleus/chemistry
- Paraventricular Hypothalamic Nucleus/metabolism
- Prefrontal Cortex/chemistry
- Prefrontal Cortex/metabolism
- RNA, Messenger/genetics
- Raphe Nuclei/chemistry
- Raphe Nuclei/metabolism
- Receptor, Serotonin, 5-HT1B
- Receptors, Glucocorticoid/genetics
- Receptors, Glucocorticoid/metabolism
- Receptors, Serotonin/analysis
- Receptors, Serotonin/metabolism
- Receptors, Serotonin, 5-HT1
- Serotonin Receptor Agonists/pharmacology
- Tritium
- Up-Regulation/genetics
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Affiliation(s)
- J Farisse
- INSERM U.501, Laboratoire d'Interactions Fonctionnelles en Neuroendocrinologie, IFR Jean-Roche, Université de la Méditerranée, UER de Médecine Nord, Boulevard Pierre Dramard, 13916, Marseille, France
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11
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Hanson LA, Gorzalka BB. The influence of corticosterone on serotonergic stereotypy and sexual behavior in the female rat. Behav Brain Res 1999; 104:27-35. [PMID: 11125740 DOI: 10.1016/s0166-4328(99)00046-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The effects of adrenalectomy and chronic corticosterone treatment on sexual behavior in the ovariectomized female rat were investigated. The serotonergic type 2A (5-HT2A) receptor-mediated behavior 'wet dog shakes' (WDS) was measured concurrently. In Experiment 1, adrenalectomy reduced the frequency of WDS following the administration of the 5-HT(2A/2C) receptor agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) but had no effect on spontaneous WDS. In Experiment 2, chronic corticosterone treatment increased DOI-induced WDS in both adrenalectomized and sham-adrenalectomized rats. In Experiment 3, adrenalectomized and sham-adrenalectomized rats were compared on measures of spontaneous WDS and sexual behavior following the administration of estrogen alone, or estrogen in combination with progesterone. Chronic corticosterone and acute progesterone administration increased WDS and facilitated sexual receptivity and proceptivity, while adrenalectomy decreased WDS, facilitated sexual receptivity and inhibited proceptivity. These findings suggest that the behavioral effects seen following hypothalamic-pituitary-adrenal (HPA) axis disruption may, in part, be mediated by altered 5-HT2A receptor responsivity.
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Affiliation(s)
- L A Hanson
- Department of Psychology, The University of British Columbia, Vancouver, Canada
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12
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Gorzalka BB, Hanson LA, Brotto LA. Chronic stress effects on sexual behavior in male and female rats: mediation by 5-HT2A receptors. Pharmacol Biochem Behav 1998; 61:405-12. [PMID: 9802835 DOI: 10.1016/s0091-3057(98)00106-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The effects of chronic psychosocial stress on sexual behavior and on the serotonergic type 2A (5-HT2A) receptor-mediated behavior "wet dog shakes" (WDS) were investigated in male and female rats. In Experiment 1, both bilaterally adrenalectomized and sham-adrenalectomized female rats were assigned to either a psychosocial stress condition or a control condition for 62 days. On the 63rd day, estrogen-primed females were compared on measures of sexual behavior and WDS. Immediately after the behavioral tests, the same rats were primed with a subthreshold level of progesterone. Three hours after the administration of progesterone, rats were again scored for sexual behavior and WDS. Psychosocial stress was found to facilitate sexual behavior and increase WDS in sham-adrenalectomized female rats providing they were primed with both estrogen and progesterone. In Experiment 2, intact male rats were assigned to either the psychosocial stress condition or the control condition for 30 days. On the 31st day, males were compared on measures of sexual behavior and WDS. No significant differences were revealed on the spontaneous expression of sexual behavior and WDS. Subsequently, males were retested following the administration of the 5-HT2A agonist, DOI. Psychosocial stress resulted in a significant decrease in male sexual behavior and a concurrent increase in WDS, following the administration of DOI. Taken together, these results suggest that chronic psychosocial stress facilitates female sexual behavior and inhibits male sexual behavior, and that the effects of stress on sexual behavior may be mediated by 5-HT2A receptor activity.
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Affiliation(s)
- B B Gorzalka
- Department of Psychology, The University of British Columbia, Vancouver, Canada
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13
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Gorzalka BB, Hanson LA. Sexual behavior and wet dog shakes in the male rat: regulation by corticosterone. Behav Brain Res 1998; 97:143-51. [PMID: 9867239 DOI: 10.1016/s0166-4328(98)00035-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The potential involvement of adrenal steroids in the regulation of 'wet dog shakes' (WDS) and sexual behavior was investigated in male rats treated or not with the serotonergic type 2A (5-HT2A) agonist DOI (5-HT2A receptor agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane). In Experiment 1, the frequency of both spontaneous and DOI-induced WDS were compared in adrenalectomized and sham-adrenalectomized rats. Adrenalectomy significantly reduced the frequency of DOI-induced WDS. In Experiment 2, adrenalectomized and sham-adrenalectomized rats received either corticosterone or oil chronically and were again scored for WDS behavior. Corticosterone effectively blocked the adrenalectomy-induced reduction of WDS in the DOI treatment condition. In Experiment 3, intact male rats were chronically administered either corticosterone or oil treatment. Animals were then compared on measures of both spontaneous and DOI-induced WDS and sexual behavior. Corticosterone significantly increased WDS and inhibited sexual behavior in both the spontaneous and DOI treatment conditions. These results suggest that the adrenal steroid corticosterone is important in the regulation of WDS and sexual behavior in the male rat and that this regulation may be mediated by activity at 5-HT2A receptors.
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Affiliation(s)
- B B Gorzalka
- Department of Psychology, The University of British Columbia, Vancouver, Canada.
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14
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Brotto LA, Gorzalka BB, Hanson LA. Effects of housing conditions and 5-HT2A activation on male rat sexual behavior. Physiol Behav 1998; 63:475-9. [PMID: 9523886 DOI: 10.1016/s0031-9384(97)00482-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Adult male rats were housed individually or in groups for a period of 39 days. In Experiment 1, the effects of housing conditions on sexual behavior and concurrent spontaneous "wet dog shaking" (WDS) were investigated. Individual housing significantly impaired male sexual behavior and resulted in a trend toward increased WDS. In Experiment 2, the effects of housing conditions were examined following administration of the serotonergic type 2A (5-HT2A) agonist DOI. Individual housing significantly increased DOI-induced WDS. The implications of these findings are discussed in the context of stress-induced corticosterone secretion and the possible regulatory effect on 5-HT2A receptors.
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Affiliation(s)
- L A Brotto
- Department of Psychology, The University of British Columbia, Vancouver, Canada
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15
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Abstract
Fluoxetine (FLX) and other specific serotonin uptake inhibitors (SSRIs) have become the drugs of choice for treating depression. However, only a limited number of studies have addressed the effects of FLX on immune cell function. Our lab has measured the effects of both acute and chronic FLX administration on two functions of cell-mediated immunity, mitogen-induced lymphocyte proliferation (MILP) and natural killer cell cytolytic activity (NKCA). In this article we report that acute FLX administration (10 mg/kg) resulted in a dose- and time-dependent decrease in MILP and NKCA. MILP was more sensitive than NKCA to FLX, requiring lower doses for inhibition; however, the effects were more transient. Following chronic FLX administration, these effects were no longer observed, suggesting that an apparent tolerance to these particular measures of cell-mediated immunity had developed. Finally, a single microinjection of FLX directly into the lateral ventricle produced similar suppressive effects on MILP and NKCA, suggesting that the immunomodulatory mechanism may have a central component.
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Affiliation(s)
- T C Pellegrino
- Department of Pharmacology, Georgetown University, School of Medicine, Washington, DC 20007, USA
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16
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Le Poul E, Laaris N, Hamon M, Lanfumey L. Fluoxetine-induced desensitization of somatodendritic 5-HT1A autoreceptors is independent of glucocorticoid(s). Synapse 1997; 27:303-12. [PMID: 9372553 DOI: 10.1002/(sici)1098-2396(199712)27:4<303::aid-syn4>3.0.co;2-g] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Previous in vitro studies showed that glucocorticoid receptor activation (notably by corticosterone) could induce a functional desensitization of somatodendritic 5-HT1A autoreceptors in the dorsal raphe nucleus [Laaris et al. (1995) Neuropharmacology 34:1201-1210], similar to that due to in vivo subchronic treatment with a 5-HT reuptake inhibitor, such as fluoxetine, in rats. In the present study, we investigated whether a link might exist between these effects, i.e., whether glucocorticoid receptor activation could be responsible for the fluoxetine-induced desensitization of 5-HT1A autoreceptors. In vitro recording in the dorsal raphe nucleus of brain-stem slices showed that subchronic treatment with fluoxetine (5 mg/kg intraperitoneally (i.p.), daily for 3-7 days) significantly reduced the potency of the 5-HT1A receptor agonist ipsapirone to inhibit the firing rate of serotoninergic neurons. Parallel experiments in adrenalectomized and sham-operated rats indicated that subchronic fluoxetine treatment produced a similar shift to the right of the ipsapirone inhibition curve in both groups of animals. Furthermore, the subchronic blockade of glucocorticoid receptors by RU 38486 (25 mg/kg subcutaneously (s.c.), daily) in intact rats treated with fluoxetine (5 mg/kg i.p., daily for 3 days) did not affect the ability of the latter treatment to reduce the potency of ipsapirone to inhibit the firing of serotoninergic neurons. These data suggest that glucocorticoid receptors (and their possible activation by corticosterone) are not involved in the functional desensitization of somatodendritic 5-HT1A autoreceptors, which occurs during long-term treatment with a serotonin reuptake inhibitor such as fluoxetine.
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Affiliation(s)
- E Le Poul
- NeuroPsychoPharmacologie, INSERM U.288, CHU Pitié-Salpêtrière, Paris, France
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17
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Chaouloff F, Kulikov A, Mormède P. Repeated DOI and SR 46349B treatments do not affect elevated plus-maze anxiety despite opposite effects on cortical 5-HT2A receptors. Eur J Pharmacol 1997; 334:25-9. [PMID: 9346323 DOI: 10.1016/s0014-2999(97)01197-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We report the consequences of a 4-day treatment (b.i.d) with the 5-HT2A,2B,2C receptor agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI, 1.5 mg/kg) or the selective 5-HT2A receptor antagonist trans-4-[(3Z)3-(2-dimethylaminoethyl)oxyimino-3-(2-fluorophe nyl)propen-1-yl]phenol hemifumarate (SR 46349B, 7.5 mg/kg) on (i) anxiety-related behaviour in an elevated plus-maze, and (ii) specific [3H]ketanserin binding at central 5-HT2A receptors, in Roman rats. Neither DOI nor SR 46349B pretreatment affected the behaviour in the open arms of the elevated plus-maze; however, DOI pretreatment promoted discrete changes in the closed arm entries. The Bmax value of [3H]ketanserin binding at cortical 5-HT2A receptors was decreased by repeated DOI pretreatment. Conversely, Bmax, but also KD, values were increased by SR 46349B pretreatment. Thus, changes at central 5-HT2A receptors may occur without there being changes in anxiety-related behaviour in the elevated plus-maze.
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Affiliation(s)
- F Chaouloff
- Génétique du Stress, INSERM CJF 94-05 INRA, Institut Francois Magendie, Bordeaux, France.
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18
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Yamada J, Sugimoto Y, Yoshikawa T, Horisaka K. Effects of adrenodemedullation and adrenalectomy on the 5-HT2 receptor agonists DOI-and mCPP-induced hypophagia in rats. Neurosci Lett 1996; 209:113-6. [PMID: 8761995 DOI: 10.1016/0304-3940(96)12613-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Effects of adrenodemedullation and adrenalectomy on the serotonin2 (5-HT2) receptor agonists-induced hypophagia were investigated. Hypophagia induced by both the 5-HT2A/2C, receptor agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) and the 5-HT2C-receptor agonist 1-(3-chlorophenyl)piperazine (mCPP) were not affected by adrenodemedullation. In adrenalectomized rats. DOI did not induce hypophagia, while mCPP elicited apparent effects. These results suggest that neither DOI- nor mCPP-induced hypophagia was not associated with adrenaline release from the adrenal medulla. Moreover, our results suggest that DOI-induced hypophagia is involved in corticosterone-sensitive feeding, although other mechanisms which are not related to corticosterone are involved in mCPP-induced anorexia.
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Affiliation(s)
- J Yamada
- Department of Pharmacology, Kobe Pharmaceutical University, Japan
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19
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Abstract
Twenty five years ago, experimental procedures such as adrenalectomy and corticosteroid administration (to intact rats) allowed the recognition of direct and indirect controls of central 5-HT synthesis rate by corticosteroids. These effects indicated that the activity of the hypothalamo-pituitary-adrenal (HPA) axis, whether under basal conditions or during stress, is endowed with a modulatory action upon serotonergic neurons. Nowadays, in situ hybridisation, in vitro autoradiography, and radioligand binding on the one hand, and electrophysiological, behavioural, and neuroendocrinological responses on the other hand, are tools that allow the analysis of direct corticosteroid effects upon 5-HT receptors. Among the dozen of 5-HT receptors identified so far, four receptors (namely the 5-HT1A, 5-HT1B, 5-HT2A, and 5-HT2C receptors)--and the 5-HT uptake system--have been the focus of studies aimed at detecting corticosteroid modulatory effects. The results that are reviewed herein indicate that hippocampal 5-HT1A receptors are under the tonic inhibitory control of corticosterone. This control is directly exerted at the level of the 5-HT1A receptor gene, essentially through mineralocorticoid receptors; as well, electrophysiological findings bring support for an additional modulation of hippocampal 5-HT1A receptor-mediated functions by indirect (ie 5-HT1A receptor gene-independent) genomic actions of corticosteroids. In keeping with the respective effects of stressful stimuli and psychotropic drugs upon the HPA axis and central serotonergic systems, it is likely that these corticosteroid-5-HT1A receptor interactions in the hippocampus have consequences in the pathophysiology of mood disorders. However, because the data regarding a corticosteroid control of other 5-HT receptors are either scarce and contradictory (eg 5-HT1B, 5-HT2A, 5-HT2C receptors and 5-HT uptake systems) or lacking, it is at the present time unknown whether corticosteroids exert other effects on 5-HT receptor-mediated functions, including those related to homeostasis.
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Affiliation(s)
- F Chaouloff
- Génétique du Stress, CJF 94-05 Inserm-Inra, Université Bordeaux II, France
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Chaouloff F, Baudrie V, Coupry I. Effects of chlorisondamine and restraint on cortical [3H]ketanserin binding, 5-HT2A receptor-mediated head shakes, and behaviours in models of anxiety. Neuropharmacology 1994; 33:449-56. [PMID: 7984283 DOI: 10.1016/0028-3908(94)90075-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A recent study has indicated that ganglionic transmission mediates acute restraint-elicited increases in brain tryptophan (5-HT precursor) levels, 5-HT synthesis and (possibly) release. Because restraint-induced release of 5-HT has been shown to be associated with a paradoxical increase in cortical 5-HT2A receptor binding, we have examined the influence of 5-HT synthesis/release upon cortical 5-HT2A receptor binding and 5-HT2A receptor-mediated head shakes in 3-hr restrained rats pretreated with the ganglionic blocker chlorisondamine. In keeping with past reports regarding the effects of restraint and ganglionic blockade upon anxiety, we have also measured the behavioural effects of restraint and/or chlorisondamine in two animal models of anxiety, the elevated plus-maze and the social interaction test. Chlorisondamine pretreatment (2.5 mg/kg, 20 min beforehand) prevented restraint-elicited defaecation and body weight decreases. Although stress amplified the head shake response to the injection of the 5-HT2A/5-HT2C receptor agonist 1-(4-iodo-2,5-dimethoxyphenyl)-2-aminopropane (DOI, 1 or 2 mg/kg 2 hr after the end of restraint), cortical [3H]ketanserin binding remained unaltered. Chlorisondamine treatment was inactive, except for the amplification of the head shake response to DOI (2 mg/kg) in restrained rats. When exposed to the social interaction test, neither restraint nor chlorisondamine affected social interaction, locomotion, or rearings. In the elevated plus-maze, the percent number of open arms entered and the total number of arms entered were decreased by acute restraint, whilst chlorisondamine pretreatment was inactive.
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Affiliation(s)
- F Chaouloff
- Laboratoire de Pharmacologie, Groupe de Neuropharmacologie, CNRS, CHU Necker, Paris, France
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