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Collins SA, Stinson HE, Himes A, Nestor-Kalinoski A, Ninan I. Sex-specific modulation of the medial prefrontal cortex by glutamatergic median raphe neurons. SCIENCE ADVANCES 2023; 9:eadg4800. [PMID: 37948526 PMCID: PMC10637752 DOI: 10.1126/sciadv.adg4800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 10/13/2023] [Indexed: 11/12/2023]
Abstract
A substantial proportion of raphe neurons are glutamatergic. However, little is known about how these glutamatergic neurons modulate the forebrain. We investigated how glutamatergic median raphe nucleus (MRN) input modulates the medial prefrontal cortex (mPFC), a critical component of fear circuitry. We show that vesicular glutamate transporter 3 (VGLUT3)-expressing MRN neurons activate VGLUT3- and somatostatin-expressing neurons in the mPFC. Consistent with this modulation of mPFC GABAergic neurons, activation of MRN (VGLUT3) neurons enhances GABAergic transmission in mPFC pyramidal neurons and attenuates fear memory in female but not male mice. Serotonin plays a key role in MRN (VGLUT3) neuron-mediated GABAergic plasticity in the mPFC. In agreement with these female-specific effects, we observed sex differences in glutamatergic transmission onto MRN (VGLUT3) neurons and in mPFC (VGLUT3) neuron-mediated dual release of glutamate and GABA. Our results demonstrate a cell type-specific modulation of the mPFC by MRN (VGLUT3) neurons and reveal a sex-specific role of this neuromodulation in mPFC synaptic plasticity.
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Affiliation(s)
- Stuart A. Collins
- Department of Neurosciences, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Hannah E. Stinson
- Department of Neurosciences, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Amanda Himes
- Department of Neurosciences, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Andrea Nestor-Kalinoski
- Department of Surgery, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Ipe Ninan
- Department of Neurosciences, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
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2
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Lemes JA, Silva MSCF, Gonçalves BSM, Céspedes IC, Viana MB. Deep Brain Stimulation of the dorsal raphe induces anxiolytic and panicolytic-like effects and alters serotonin immunoreactivity. Behav Brain Res 2023; 449:114462. [PMID: 37121276 DOI: 10.1016/j.bbr.2023.114462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 04/26/2023] [Accepted: 04/27/2023] [Indexed: 05/02/2023]
Abstract
Previously we showed that Deep Brain Stimulation (DBS) of the dorsal region (DRD) and of the lateral wings of the dorsal raphe (lwDR) respectively decreases anxiety and panic-like responses in the elevated T-maze (ETM). This study investigates neurobiological alterations which might respond for these behavioral effects. Male Wistar rats were submitted to high-frequency stimulation (100µA, 100Hz) of the DRD or of the lwDR for 1h, and subsequently tested in the avoidance or escape tasks of the ETM. Since serotonin (5-HT) reuptake inhibitors are first line pharmacological treatment for anxiety disorders, we also tested the effects of chronic fluoxetine administration (10mg/kg, IP, 21 days) on a separate group of rats. An open field was used for locomotor activity assessment. Additionally, we evaluated c-Fos immunoreactivity (Fos-ir) in serotonergic cells of the dorsal raphe (DR). Results showed that DBS of the DRD decreases avoidance reactions, an anxiolytic-like effect, without altering escape or locomotor activity. Both fluoxetine and DBS of the lwDR decreased escape responses in the ETM, a panicolytic-like effect, without altering avoidance measurements or locomotor activity. While DBS of the DRD decreased double immunostaining in the DRD, DBS of the lwDR increased Fos-ir and double immunostaining in the DRD and lwDR. Fluoxetine also increased double immunostaining in the lwDR and in the DRV but decreased it in the DRD. These results suggest that both the anxiolytic and panicolytic-like effects of DBS and fluoxetine are related to 5-HT modulation in different subnuclei of the DR.
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Affiliation(s)
- J A Lemes
- Departamento de Biociências, Federal University of São Paulo (UNIFESP), Santos, Brazil
| | - M S C F Silva
- Departamento de Biociências, Federal University of São Paulo (UNIFESP), Santos, Brazil
| | - B S M Gonçalves
- Departamento de Biociências, Federal University of São Paulo (UNIFESP), Santos, Brazil
| | - I C Céspedes
- Departamento de Morfologia e Genética, Escola Paulista de Medicina, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
| | - M B Viana
- Departamento de Biociências, Federal University of São Paulo (UNIFESP), Santos, Brazil.
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Beyeler A, Ju A, Chagraoui A, Cuvelle L, Teixeira M, Di Giovanni G, De Deurwaerdère P. Multiple facets of serotonergic modulation. PROGRESS IN BRAIN RESEARCH 2021; 261:3-39. [PMID: 33785133 DOI: 10.1016/bs.pbr.2021.02.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The serotonergic system of the central nervous system (CNS) has been implicated in a broad range of physiological functions and behaviors, such as cognition, mood, social interaction, sexual behavior, feeding behavior, sleep-wake cycle and thermoregulation. Serotonin (5-hydroxytryptamine, 5-HT) establishes a plethora of interactions with neurochemical systems in the CNS via its numerous 5-HT receptors and autoreceptors. The facets of this control are multiple if we consider the molecular actors playing a role in the autoregulation of 5-HT neuron activity including the 5-HT1A, 5-HT1B, 5-HT1D, 5-HT2B, 5-HT7 receptors as well as the serotonin transporter. Moreover, extrinsic loops involving other neurotransmitters giving the other 5-HT receptors the possibility to impact 5-HT neuron activity. Grasping the complexity of these interactions is essential for the development of a variety of therapeutic strategies for cognitive defects and mood disorders. Presently we can illustrate the plurality of the mechanisms and only conceive that these 5-HT controls are likely not uniform in terms of regional and neuronal distribution. Our understanding of the specific expression patterns of these receptors on specific circuits and neuronal populations are progressing and will expand our comprehension of the function and interaction of these receptors with other chemical systems. Thus, the development of new approaches profiling the expression of 5-HT receptors and autoreceptors should reveal additional facets of the 5-HT controls of neurochemical systems in the CNS.
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Affiliation(s)
- Anna Beyeler
- Neurocentre Magendie, INSERM 1215, Université de Bordeaux, Bordeaux, France.
| | - Anes Ju
- Neurocentre Magendie, INSERM 1215, Université de Bordeaux, Bordeaux, France
| | - Abdeslam Chagraoui
- Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Institute for Research and Innovation in Biomedicine of Normandy (IRIB), Normandie University, UNIROUEN, INSERM U1239, Rouen, France; Department of Medical Biochemistry, Rouen University Hospital, Rouen, France
| | - Lise Cuvelle
- Centre National de La Recherche Scientifique, Institut des Neurosciences Intégratives et Cognitives d'Aquitaine, UMR 5287, Bordeaux, France
| | - Maxime Teixeira
- Centre National de La Recherche Scientifique, Institut des Neurosciences Intégratives et Cognitives d'Aquitaine, UMR 5287, Bordeaux, France
| | - Giuseppe Di Giovanni
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta; Neuroscience Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom.
| | - Philippe De Deurwaerdère
- Centre National de La Recherche Scientifique, Institut des Neurosciences Intégratives et Cognitives d'Aquitaine, UMR 5287, Bordeaux, France
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Colangeli R, Teskey GC, Di Giovanni G. Endocannabinoid-serotonin systems interaction in health and disease. PROGRESS IN BRAIN RESEARCH 2021; 259:83-134. [PMID: 33541682 DOI: 10.1016/bs.pbr.2021.01.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Endocannabinoid (eCB) and serotonin (5-HT) neuromodulatory systems work both independently and together to finely orchestrate neuronal activity throughout the brain to strongly sculpt behavioral functions. Surprising parallelism between the behavioral effects of 5-HT and eCB activity has been widely reported, including the regulation of emotional states, stress homeostasis, cognitive functions, food intake and sleep. The distribution pattern of the 5-HT system and the eCB molecular elements in the brain display a strong overlap and several studies report a functional interplay and even a tight interdependence between eCB/5-HT signaling. In this review, we examine the available evidence of the interaction between the eCB and 5-HT systems. We first introduce the eCB system, then we describe the eCB/5-HT crosstalk at the neuronal and synaptic levels. Finally, we explore the potential eCB/5-HT interaction at the behavioral level with the implication for psychiatric and neurological disorders. The precise elucidation of how this neuromodulatory interaction dynamically regulates biological functions may lead to the development of more targeted therapeutic strategies for the treatment of depressive and anxiety disorders, psychosis and epilepsy.
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Affiliation(s)
- Roberto Colangeli
- Section of Neuroscience and Cell Biology, Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy; Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.
| | - G Campbell Teskey
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
| | - Giuseppe Di Giovanni
- Laboratory of Neurophysiology, Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Msida, Malta; Neuroscience Division, School of Biosciences, Cardiff University, Cardiff, United Kingdom
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Delcourte S, Etievant A, Haddjeri N. Role of central serotonin and noradrenaline interactions in the antidepressants' action: Electrophysiological and neurochemical evidence. PROGRESS IN BRAIN RESEARCH 2021; 259:7-81. [PMID: 33541681 DOI: 10.1016/bs.pbr.2021.01.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The development of antidepressant drugs, in the last 6 decades, has been associated with theories based on a deficiency of serotonin (5-HT) and/or noradrenaline (NA) systems. Although the pathophysiology of major depression (MD) is not fully understood, numerous investigations have suggested that treatments with various classes of antidepressant drugs may lead to an enhanced 5-HT and/or adapted NA neurotransmissions. In this review, particular morpho-physiological aspects of these systems are first considered. Second, principal features of central 5-HT/NA interactions are examined. In this regard, the effects of the acute and sustained antidepressant administrations on these systems are discussed. Finally, future directions including novel therapeutic strategies are proposed.
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Affiliation(s)
- Sarah Delcourte
- Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, Bron, France
| | - Adeline Etievant
- Integrative and Clinical Neurosciences EA481, University of Bourgogne Franche-Comté, Besançon, France
| | - Nasser Haddjeri
- Univ Lyon, Université Claude Bernard Lyon 1, Inserm, Stem Cell and Brain Research Institute U1208, Bron, France.
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Jiang JL, El Mansari M, Blier P. Triple reuptake inhibition of serotonin, norepinephrine, and dopamine increases the tonic activation of α 2-adrenoceptors in the rat hippocampus and dopamine levels in the nucleus accumbens. Prog Neuropsychopharmacol Biol Psychiatry 2020; 103:109987. [PMID: 32474007 DOI: 10.1016/j.pnpbp.2020.109987] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 05/26/2020] [Accepted: 05/26/2020] [Indexed: 01/03/2023]
Abstract
Clinical studies have shown the therapeutic efficacy of an increase in dopamine (DA) transmission in treatment of major depressive disorder (MDD). In the present study, we investigated whether blockade of DA transporters in addition to serotonin (5-HT) and norepinephrine (NE) produced additional adaptations of monoaminergic systems. In vivo electrophysiological recordings were carried out in male anesthetized rats. Vehicle, the 5-HT reuptake inhibitor escitalopram, the NE/DA reuptake blocker nomifensine and their combination (triple reuptake inhibition; TRI) were delivered for 2 or 14 days. Firing activity of NE, 5-HT and DA neurons was assessed. Tonic activation of 5-HT1A receptors and α1- and α2-adrenoceptors was determined in the hippocampus and extracellular DA levels in the nucleus accumbens (NAc). Unlike escitalopram, nomifensine and TRI administration increased the tonic activation of α2-adrenoceptors in the hippocampus despite decreasing NE neuronal firing activity after 2 and 14 days of administration. The firing activity of 5-HT neurons was increased after prolonged nomifensine and TRI regimens, while addition of nomifensine to escitalopram prevented the early 2-day suppression of firing by 5-HT reuptake inhibition. The tonic activation of 5-HT1A receptors was enhanced only with escitalopram. Whereas escitalopram and nomifensine decreased firing activity of DA neurons after a 2-day administration, their combination normalized it to baseline level after 14 days; this was accompanied by a robust increase in extracellular DA levels in the NAc. In summary, these results indicate that TRI increases NE and DA but not 5-HT transmission, suggesting a differential efficacy profile in MDD patients.
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Affiliation(s)
- Jojo L Jiang
- University of Ottawa Institute of Mental Health Research, 1145 Carling Avenue, Ottawa, Ontario K1Z 7K4, Canada
| | - Mostafa El Mansari
- University of Ottawa Institute of Mental Health Research, 1145 Carling Avenue, Ottawa, Ontario K1Z 7K4, Canada.
| | - Pierre Blier
- University of Ottawa Institute of Mental Health Research, 1145 Carling Avenue, Ottawa, Ontario K1Z 7K4, Canada
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Murray BP, Carpenter JE, Sayers J, Yeh M, Beau J, Kiernan EA, Wolf MJ, Bolton TA, Kazzi Z. Two Cases of Serotonin Syndrome After Bupropion Overdose Treated With Cyproheptadine. J Emerg Med 2020; 60:e67-e71. [PMID: 33308914 DOI: 10.1016/j.jemermed.2020.10.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/21/2020] [Accepted: 10/19/2020] [Indexed: 10/22/2022]
Abstract
BACKGROUND Bupropion is not known to have direct serotonin agonism or inhibit serotonin reuptake. In spite of this, it has been implicated as a causative agent of serotonin syndrome. We highlight two cases of single-agent bupropion overdose that subsequently met the diagnosis of serotonin syndrome by the Hunter criteria, despite the absence of direct serotonergic agents. CASE 1: A 14-year-old boy intentionally ingested an estimated 30 bupropion 75-mg immediate-release tablets. He presented in status epilepticus, was intubated, and was placed on midazolam and fentanyl infusions. He developed tremor, ankle clonus, and agitation. He was administered cyproheptadine for presumed serotonin syndrome with temporal improvement in his symptoms. CASE 2: A 19-year-old woman intentionally ingested an estimated 53 bupropion 150-mg extended-release tablets. She had a seizure and required sedation and intubation. During her course, she developed hyperthermia, inducible clonus, and hyperreflexia. She was treated with cyproheptadine without temporal improvement of symptoms but improved the following day. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Although bupropion is not known to be directly serotonergic, it has been implicated as the single causative agent after overdose. This may be due to an indirect increase in activity of serotonergic cells. In these cases, bupropion overdose resulted in a clinical presentation consistent with serotonin syndrome, with the first having a temporal improvement after treatment with cyproheptadine. Physicians need to be aware of the potential serotonergic activity of bupropion for accurate assessment and treatment of this dangerous condition.
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Affiliation(s)
- Brian P Murray
- Department of Emergency Medicine, Wright State Boonsoft School of Medicine, Dayton, Ohio
| | | | - Joshua Sayers
- Department of Emergency Medicine, Wright State Boonsoft School of Medicine, Dayton, Ohio
| | - Michael Yeh
- Emory University School of Medicine, Atlanta, Georgia
| | - Jordan Beau
- Emory University School of Medicine, Atlanta, Georgia
| | | | - Matthew J Wolf
- Department of Emergency Medicine, Wright State Boonsoft School of Medicine, Dayton, Ohio
| | | | - Ziad Kazzi
- Emory University School of Medicine, Atlanta, Georgia
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8
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Murray BP, Carpenter J, Moran TP, Calello DP, Kazzi Z. In Response to Borgsteede et al. About Bupropion and Serotonin Toxicity. J Med Toxicol 2020; 16:335-336. [DOI: 10.1007/s13181-020-00764-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 02/15/2020] [Accepted: 02/15/2020] [Indexed: 11/28/2022] Open
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Matthiesen M, Mendes LD, Spiacci A, Fortaleza EA, Corrêa FM, Zangrossi H. Serotonin 2C receptors in the basolateral amygdala mediate the anxiogenic effect caused by serotonergic activation of the dorsal raphe dorsomedial subnucleus. J Psychopharmacol 2020; 34:391-399. [PMID: 31637976 DOI: 10.1177/0269881119882797] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Stimulation of serotonergic neurons within the dorsal raphe dorsomedial subnucleus facilitates inhibitory avoidance acquisition in the elevated T-maze. It has been hypothesized that such anxiogenic effect is due to serotonin release in the basolateral nucleus of the amygdala, where facilitation of serotonin 2C receptor-mediated neurotransmission increases anxiety. Besides the dorsal raphe dorsomedial subnucleus, the dorsal raphe caudal subnucleus is recruited by anxiogenic stimulus/situations. However, the behavioral consequences of pharmacological manipulation of this subnucleus are still unknown. AIMS Investigate whether blockade of serotonin 2C receptors in the basolateral nucleus of the amygdala counteracts the anxiogenic effect caused by the stimulation of dorsal raphe dorsomedial subnucleus serotonergic neurons. Evaluate the effects caused by the excitatory amino acid kainic acid or serotonin 1A receptor-modulating drugs in the dorsal raphe caudal subnucleus. METHODS Male Wistar rats were tested in the elevated T-maze and light-dark transition tests after intra-basolateral nucleus of the amygdala injection of the serotonin 2C receptor antagonist SB-242084 (6-chloro-2,3-dihydro-5-methyl-N-[6-[(2-methyl-3-pyridinyl)oxy]-3-pyridinyl]-1H-indole-1-carboxyamide dihydrochloride) followed by intra-dorsal raphe dorsomedial subnucleus administration of the serotonin 1A receptor antagonist WAY-100635 (N-[2-[4-2-methoxyphenyl)-1-piperazinyl]ethyl]-N-2-pyridinil-cyclohexanecarboxamide maleate). In the dorsal raphe caudal subnucleus, animals were injected with kainic acid, WAY-100635 or the serotonin 1A receptor agonist 8-OH-DPAT ((±)-8-hydroxy-2-(di-n-propylamino) tetralin hydrobromide) and tested in the elevated T-maze. RESULTS SB-242084 in the basolateral nucleus of the amygdala blocked the anxiogenic effect caused by the injection of WAY-100635 in the dorsal raphe dorsomedial subnucleus. Kainic acid in the dorsal raphe caudal subnucleus increased anxiety, but also impaired escape expression in the elevated T-maze. Neither WAY-100635 nor 8-OH-DPAT in the dorsal raphe caudal subnucleus affected rat's behavior in the elevated T-maze. CONCLUSION Serotonin 2C receptors in the basolateral nucleus of the amygdala mediate the anxiogenic effect caused by the stimulation of serotonergic neurons in the dorsal raphe dorsomedial subnucleus. The dorsal raphe caudal subnucleus regulates anxiety- and panic-like behaviors, presumably by a serotonin 1A receptor-independent mechanism.
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Affiliation(s)
- Melina Matthiesen
- Department of Pharmacology, University of São Paulo, São Paulo, Brazil
| | - Leonardo D Mendes
- Department of Pharmacology, University of São Paulo, São Paulo, Brazil
| | - Ailton Spiacci
- Department of Pharmacology, University of São Paulo, São Paulo, Brazil
| | | | | | - Hélio Zangrossi
- Department of Pharmacology, University of São Paulo, São Paulo, Brazil
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10
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Murray B, Carpenter J, Dunkley C, Moran TP, Kiernan EA, Rianprakaisang T, Alsukaiti WS, Calello DP, Kazzi Z. Single-Agent Bupropion Exposures: Clinical Characteristics and an Atypical Cause of Serotonin Toxicity. J Med Toxicol 2019; 16:12-16. [PMID: 31823333 DOI: 10.1007/s13181-019-00749-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 11/08/2019] [Accepted: 11/14/2019] [Indexed: 10/25/2022] Open
Abstract
INTRODUCTION Bupropion is the only Food and Drug Administration-approved synthetic cathinone. It increases the release of norepinephrine in the locus coeruleus and dorsal raphe nucleus, causing an increase in the frequency of serotonergic neuron firing. The diagnosis of serotonin toxicity (ST) from bupropion poisoning is controversial due to the lack of direct serotonergic activity. Nonetheless, there is one documented report of ST after single-agent bupropion overdose and multiple reports describing polypharmacy overdoses where bupropion may have contributed to ST. METHODS This is a retrospective analysis of data collected by the Toxicology Investigators Consortium (ToxIC), a prospective multi-center toxico-surveillance and research network registry, from 2014 to 2017. Cases were identified if ST was a clinical effect and bupropion was the single agent listed. Data is presented descriptively. RESULTS Of the 266 recorded single bupropion overdoses, the most common symptoms were seizures (47.1%), tachycardia (greater than 140 bpm) (33.9%), agitation (31.7%), toxic psychosis (20.4%), and myoclonus/tremor/hyperreflexia (19%). Benzodiazepines were the most common therapy (69.2%). Thirteen patients (5.9%) were diagnosed with ST by a medical toxicologist. CONCLUSION Bupropion overdose is primarily associated with seizures, tachycardia, and agitation; bupropion may be an atypical cause of serotonin toxicity.
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Affiliation(s)
- Brian Murray
- Emory University School of Medicine, Atlanta, GA, USA. .,Georgia Poison Center, Atlanta, GA, USA.
| | - Joseph Carpenter
- Emory University School of Medicine, Atlanta, GA, USA.,Georgia Poison Center, Atlanta, GA, USA
| | - Camille Dunkley
- Emory University School of Medicine, Atlanta, GA, USA.,Georgia Poison Center, Atlanta, GA, USA
| | - Tim P Moran
- Emory University School of Medicine, Atlanta, GA, USA
| | - Emily A Kiernan
- Emory University School of Medicine, Atlanta, GA, USA.,Georgia Poison Center, Atlanta, GA, USA
| | | | | | | | - Ziad Kazzi
- Emory University School of Medicine, Atlanta, GA, USA.,Georgia Poison Center, Atlanta, GA, USA
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Vilela-Costa HH, Spiacci A, Bissolli IG, Zangrossi H. A Shift in the Activation of Serotonergic and Non-serotonergic Neurons in the Dorsal Raphe Lateral Wings Subnucleus Underlies the Panicolytic-Like Effect of Fluoxetine in Rats. Mol Neurobiol 2019; 56:6487-6500. [DOI: 10.1007/s12035-019-1536-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 02/22/2019] [Indexed: 01/04/2023]
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12
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Belmer A, Quentin E, Diaz SL, Guiard BP, Fernandez SP, Doly S, Banas SM, Pitychoutis PM, Moutkine I, Muzerelle A, Tchenio A, Roumier A, Mameli M, Maroteaux L. Positive regulation of raphe serotonin neurons by serotonin 2B receptors. Neuropsychopharmacology 2018; 43:1623-1632. [PMID: 29453444 PMCID: PMC5983540 DOI: 10.1038/s41386-018-0013-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 01/10/2018] [Accepted: 01/17/2018] [Indexed: 01/03/2023]
Abstract
Serotonin is a neurotransmitter involved in many psychiatric diseases. In humans, a lack of 5-HT2B receptors is associated with serotonin-dependent phenotypes, including impulsivity and suicidality. A lack of 5-HT2B receptors in mice eliminates the effects of molecules that directly target serotonergic neurons including amphetamine derivative serotonin releasers, and selective serotonin reuptake inhibitor antidepressants. In this work, we tested the hypothesis that 5-HT2B receptors directly and positively regulate raphe serotonin neuron activity. By ex vivo electrophysiological recordings, we report that stimulation by the 5-HT2B receptor agonist, BW723C86, increased the firing frequency of serotonin Pet1-positive neurons. Viral overexpression of 5-HT2B receptors in these neurons increased their excitability. Furthermore, in vivo 5-HT2B-receptor stimulation by BW723C86 counteracted 5-HT1A autoreceptor-dependent reduction in firing rate and hypothermic response in wild-type mice. By a conditional genetic ablation that eliminates 5-HT2B receptor expression specifically and exclusively from Pet1-positive serotonin neurons (Htr2b 5-HTKO mice), we demonstrated that behavioral and sensitizing effects of MDMA (3,4-methylenedioxy-methamphetamine), as well as acute behavioral and chronic neurogenic effects of the antidepressant fluoxetine, require 5-HT2B receptor expression in serotonergic neurons. In Htr2b 5-HTKO mice, dorsal raphe serotonin neurons displayed a lower firing frequency compared to control Htr2b lox/lox mice as assessed by in vivo extracellular recordings and a stronger hypothermic effect of 5-HT1A-autoreceptor stimulation was observed. The increase in head-twitch response to DOI (2,5-dimethoxy-4-iodoamphetamine) further confirmed the lower serotonergic tone resulting from the absence of 5-HT2B receptors in serotonin neurons. Together, these observations indicate that the 5-HT2B receptor acts as a direct positive modulator of serotonin Pet1-positive neurons in an opposite way as the known 5-HT1A-negative autoreceptor.
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Affiliation(s)
- Arnauld Belmer
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France ,0000000089150953grid.1024.7Translational Research Institute, Queensland University of Technology, Brisbane, QLD 4059 Australia
| | - Emily Quentin
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France
| | - Silvina L. Diaz
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France ,grid.441705.3Instituto de Biología Celular y Neurociencia, Fac. de Cs. Exactas, Químicas y Naturales, Universidad de Morón, UBA-CONICET – Paraguay 2155, 3° piso, C1121ABG Buenos Aires, Argentina
| | - Bruno P. Guiard
- Research Center on Animal Cognition, Center for Integrative Biology, 31062 Toulouse, France ,0000 0001 0723 035Xgrid.15781.3aUniversité Paul Sabatier, 31062 Toulouse, France ,UMR5169 CNRS, 31062 Toulouse, France
| | - Sebastian P. Fernandez
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France ,0000 0004 0638 0649grid.429194.3IPMC – CNRS UMR7275 660 Route des Lucioles Sophia-Antipolis, 06560 Valbonne, France
| | - Stéphane Doly
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France ,grid.503334.2Université Clermont Auvergne, INSERM, NEURO-DOL, 63000 Clermont-Ferrand, France
| | - Sophie M. Banas
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France
| | - Pothitos M. Pitychoutis
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France ,0000 0001 2175 167Xgrid.266231.2Department of Biology and Center for Tissue Regeneration and Engineering at Dayton (TREND), University of Dayton, Dayton, OH USA
| | - Imane Moutkine
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France
| | - Aude Muzerelle
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France
| | - Anna Tchenio
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France ,0000 0001 2165 4204grid.9851.5Dept. Fundamental Neurosciences (DNF) The University of Lausanne, Lausanne, Switzerland
| | - Anne Roumier
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France
| | - Manuel Mameli
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France ,0000 0001 2165 4204grid.9851.5Dept. Fundamental Neurosciences (DNF) The University of Lausanne, Lausanne, Switzerland
| | - Luc Maroteaux
- INSERM UMR-S 839, 75005, Paris, France. .,Sorbonne Universités, UPMC Univ Paris 6, 75005, Paris, France. .,Institut du Fer à Moulin, 75005, Paris, France.
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Selvaraj S, Walker C, Arnone D, Cao B, Faulkner P, Cowen PJ, Roiser JP, Howes O. Effect of Citalopram on Emotion Processing in Humans: A Combined 5-HT 1A [ 11C]CUMI-101 PET and Functional MRI Study. Neuropsychopharmacology 2018; 43:655-664. [PMID: 28776580 PMCID: PMC5693328 DOI: 10.1038/npp.2017.166] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 07/18/2017] [Accepted: 08/01/2017] [Indexed: 12/21/2022]
Abstract
A subset of patients started on a selective serotonin reuptake inhibitor (SSRI) initially experience increased anxiety, which can lead to early discontinuation before therapeutic effects are manifest. The neural basis of this early SSRI effect is not known. Presynaptic dorsal raphe neuron (DRN) 5-HT1A receptors are known to have a critical role in affect processing. Thus we investigated the effect of acute citalopram on emotional processing and the relationship between DRN 5-HT1A receptor availability and amygdala reactivity. Thirteen (mean age 48±9 years) healthy male subjects received either a saline or citalopram infusion intravenously (10 mg over 30 min) on separate occasions in a single-blind, random order, crossover design. On each occasion, participants underwent a block design face-emotion processing task during fMRI known to activate the amygdala. Ten subjects also completed a positron emission tomography (PET) scan to quantify DRN 5-HT1A availability using [11C]CUMI-101. Citalopram infusion when compared with saline resulted in a significantly increased bilateral amygdala responses to fearful vs neutral faces (left p=0.025; right p=0.038 FWE-corrected). DRN [11C]CUMI-101 availability significantly positively correlated with the effect of citalopram on the left amygdala response to fearful faces (Z=2.51, p=0.027) and right amygdala response to happy faces (Z=2.33, p=0.032). Our findings indicate that the initial effect of SSRI treatment is to alter processing of aversive stimuli and that this is linked to DRN 5-HT1A receptors in line with evidence that 5-HT1A receptors have a role in mediating emotional processing.
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Affiliation(s)
- Sudhakar Selvaraj
- Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at Houston, Houston, TX, USA,Medical Research Council London Institute of Medical Sciences, Hammersmith Hospital, London, UK,Department of Psychiatry and Behavioral Sciences, The University of Texas Health Science Center at Houston, Biomedical and Behavioral Sciences Building (BBSB), 1941 East Road, Suite 3208 Houston, TX 77054, USA, Tel: +1 713 486 2500, Fax: +1 713 486 2553, E-mail:
| | - Chris Walker
- Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Danilo Arnone
- Institute of Psychiatry, King’s College London, Centre for Affective Disorders, London, UK,IoPPN, King’s College London, Institute of Psychiatry, Psychosis Studies, London, UK
| | - Bo Cao
- Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Paul Faulkner
- Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, CA, USA
| | - Philip J Cowen
- Department of Psychiatry, University of Oxford, Oxford, UK
| | - Jonathan P Roiser
- Institute of Cognitive Neuroscience, University College London, London, UK
| | - Oliver Howes
- Medical Research Council London Institute of Medical Sciences, Hammersmith Hospital, London, UK,IoPPN, King’s College London, Institute of Psychiatry, Psychosis Studies, London, UK,Institute of Clinical Sciences, Imperial College, Hammersmith Hospital, London, UK
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14
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Mlinar B, Montalbano A, Waider J, Lesch KP, Corradetti R. Increased functional coupling of 5-HT 1A autoreceptors to GIRK channels in Tph2 -/- mice. Eur Neuropsychopharmacol 2017; 27:1258-1267. [PMID: 29126768 DOI: 10.1016/j.euroneuro.2017.10.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Revised: 10/14/2017] [Accepted: 10/22/2017] [Indexed: 10/18/2022]
Abstract
Firing activity of serotonergic neurons is under regulatory control by somatodendritic 5-HT1A autoreceptors (5-HT1AARs). Enhanced 5-HT1AAR functioning may cause decreased serotonergic signaling in brain and has thereby been implicated in the etiology of mood and anxiety disorders. Tryptophan hydroxylase-2 knockout (Tph2-/-) mice exhibit sensitization of 5-HT1A agonist-induced inhibition of serotonergic neuron firing and thus represents a unique animal model of enhanced 5-HT1AAR functioning. To elucidate the mechanisms underlying 5-HT1AAR supersensitivity in Tph2-/- mice, we characterized the activation of G protein-coupled inwardly-rectifying potassium (GIRK) conductance by the 5-HT1A receptor agonist 5-carboxamidotryptamine using whole-cell recordings from serotonergic neurons in dorsal raphe nucleus. Tph2-/- mice exhibited a mean twofold leftward shift of the agonist concentration-response curve (p < 0.001) whereas the maximal response, proportional to the 5-HT1AAR number, was not different (p = 0.42) compared to Tph2+/- and Tph2+/+ littermates. No differences were found in the basal inwardly-rectifying potassium conductance, determined in the absence of agonist, (p = 0.80) nor in total GIRK conductance activated by intracellular application of GTP-γ-S (p = 0.69). These findings indicate increased functional coupling of 5-HT1AARs to GIRK channels in Tph2-/- mice without a concomitant increase in 5-HT1AARs and/or GIRK channel density. In addition, no changes were found in α1-adrenergic facilitation of firing (p = 0.72) indicating lack of adaptive changes Tph2-/- mice. 5-HT1AAR supersensitivity may represents a previously unrecognized cause of serotonergic system hypofunction and associated disorders and provides a possible explanation for conflicting results on the correlation between 5-HT1AAR density and depression in clinical imaging studies.
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Affiliation(s)
- Boris Mlinar
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy.
| | - Alberto Montalbano
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
| | - Jonas Waider
- Division of Molecular Psychiatry, Laboratory of Translational Neuroscience, Center of Mental Health, University of Wuerzburg, Wuerzburg, Germany
| | - Klaus-Peter Lesch
- Division of Molecular Psychiatry, Laboratory of Translational Neuroscience, Center of Mental Health, University of Wuerzburg, Wuerzburg, Germany; Laboratory of Psychiatric Neurobiology, Institute of Molecular Medicine, I.M. Sechenov First Moscow State Medical University, Moscow, Russia; Department of Translational Neuroscience, School of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Renato Corradetti
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Florence, Italy
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15
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Galanin subtype 1 and subtype 2 receptors mediate opposite anxiety-like effects in the rat dorsal raphe nucleus. Behav Brain Res 2016; 314:125-33. [DOI: 10.1016/j.bbr.2016.08.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 08/01/2016] [Accepted: 08/03/2016] [Indexed: 01/09/2023]
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16
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Affiliation(s)
- Albert Adell
- Institute of Biomedicine and Biotechnology of Cantabria, IBBTEC (CSIC, Universidad de Cantabria), 39011 Santander, Spain
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17
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Mlinar B, Montalbano A, Baccini G, Tatini F, Berlinguer Palmini R, Corradetti R. Nonexocytotic serotonin release tonically suppresses serotonergic neuron activity. ACTA ACUST UNITED AC 2016; 145:225-51. [PMID: 25712017 PMCID: PMC4338157 DOI: 10.1085/jgp.201411330] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The firing activity of serotonergic neurons in raphe nuclei is regulated by negative feedback exerted by extracellular serotonin (5-HT)o acting through somatodendritic 5-HT1A autoreceptors. The steady-state [5-HT]o, sensed by 5-HT1A autoreceptors, is determined by the balance between the rates of 5-HT release and reuptake. Although it is well established that reuptake of 5-HTo is mediated by 5-HT transporters (SERT), the release mechanism has remained unclear. It is also unclear how selective 5-HT reuptake inhibitor (SSRI) antidepressants increase the [5-HT]o in raphe nuclei and suppress serotonergic neuron activity, thereby potentially diminishing their own therapeutic effect. Using an electrophysiological approach in a slice preparation, we show that, in the dorsal raphe nucleus (DRN), continuous nonexocytotic 5-HT release is responsible for suppression of phenylephrine-facilitated serotonergic neuron firing under basal conditions as well as for autoinhibition induced by SSRI application. By using 5-HT1A autoreceptor-activated G protein-gated inwardly rectifying potassium channels of patched serotonergic neurons as 5-HTo sensors, we show substantial nonexocytotic 5-HT release under conditions of abolished firing activity, Ca(2+) influx, vesicular monoamine transporter 2-mediated vesicular accumulation of 5-HT, and SERT-mediated 5-HT transport. Our results reveal a cytosolic origin of 5-HTo in the DRN and suggest that 5-HTo may be supplied by simple diffusion across the plasma membrane, primarily from the dense network of neurites of serotonergic neurons surrounding the cell bodies. These findings indicate that the serotonergic system does not function as a sum of independently acting neurons but as a highly interdependent neuronal network, characterized by a shared neurotransmitter pool and the regulation of firing activity by an interneuronal, yet activity-independent, nonexocytotic mechanism.
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Affiliation(s)
- Boris Mlinar
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, 50121 Florence, Italy
| | - Alberto Montalbano
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, 50121 Florence, Italy
| | - Gilda Baccini
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, 50121 Florence, Italy
| | - Francesca Tatini
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, 50121 Florence, Italy
| | - Rolando Berlinguer Palmini
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, 50121 Florence, Italy
| | - Renato Corradetti
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, 50121 Florence, Italy
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18
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Courtney NA, Ford CP. Mechanisms of 5-HT1A receptor-mediated transmission in dorsal raphe serotonin neurons. J Physiol 2015; 594:953-65. [PMID: 26634643 DOI: 10.1113/jp271716] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 11/30/2015] [Indexed: 02/01/2023] Open
Abstract
KEY POINTS In the dorsal raphe nucleus, it is known that serotonin release activates metabotropic 5-HT1A autoreceptors located on serotonin neurons that leads to an inhibition of firing through the activation of G-protein-coupled inwardly rectifying potassium channels. We found that in mouse brain slices evoked serotonin release produced a 5-HT1A receptor-mediated inhibitory postsynaptic current (IPSC) that resulted in only a transient pause in firing. While spillover activation of receptors contributed to evoked IPSCs, serotonin reuptake transporters prevented pooling of serotonin in the extrasynaptic space from activating 5-HT1A -IPSCs. As a result, the decay of 5-HT1A -IPSCs was independent of the intensity of stimulation or the probability of transmitter release. These results indicate that evoked serotonin transmission in the dorsal raphe nucleus mediated by metabotropic 5-HT1A autoreceptors may occur via point-to-point synapses rather than by paracrine mechanisms. ABSTRACT In the dorsal raphe nucleus (DRN), feedback activation by Gαi/o -coupled 5-HT1A autoreceptors reduces the excitability of serotoninergic neurons, which decreases serotonin release both locally within the DRN and in projection regions. Serotonin transmission within the DRN is thought to occur via transmitter spillover and paracrine activation of extrasynaptic receptors. Here, we tested the volume transmission hypothesis in mouse DRN brain slices by recording 5-HT1A receptor-mediated inhibitory postsynaptic currents (5-HT1A -IPSCs) generated by the activation of G-protein-coupled inwardly rectifying potassium channels (GIRKs). We found that in the DRN of ePET1-EYFP mice, which selectively express enhanced yellow fluorescent protein in serontonergic neurons, the local release of serotonin generated 5-HT1A -IPSCs in serotonin neurons that rose and fell within a second. The transient activation of 5-HT1A autoreceptors resulted in brief pauses in neuron firing that did not alter the overall firing rate. The duration of 5-HT1A -IPSCs was primarily shaped by receptor deactivation due to clearance via serotonin reuptake transporters. Slowing diffusion with dextran prolonged the rise and reduced the amplitude the IPSCs and the effects were potentiated when uptake was inhibited. By examining the decay kinetics of IPSCs, we found that while spillover may allow for the activation of extrasynaptic receptors, efficient uptake by serotonin reuptake transporters (SERTs) prevented the pooling of serotonin from prolonging the duration of transmission when multiple inputs were active. Together the results suggest that the activation of 5-HT1A receptors in the DRN results from the local release of serotonin rather than the extended diffusion throughout the extracellular space.
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Affiliation(s)
- Nicholas A Courtney
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, 10900 Euclid Ave, Cleveland, OH, 44106-4970, USA
| | - Christopher P Ford
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, 10900 Euclid Ave, Cleveland, OH, 44106-4970, USA.,Department of Neurosciences, Case Western Reserve University School of Medicine, 10900 Euclid Ave, Cleveland, OH, 44106-4970, USA
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19
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Selvaraj S, Mouchlianitis E, Faulkner P, Turkheimer F, Cowen PJ, Roiser JP, Howes O. Presynaptic Serotoninergic Regulation of Emotional Processing: A Multimodal Brain Imaging Study. Biol Psychiatry 2015; 78:563-571. [PMID: 24882568 PMCID: PMC5322825 DOI: 10.1016/j.biopsych.2014.04.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Revised: 04/01/2014] [Accepted: 04/01/2014] [Indexed: 11/26/2022]
Abstract
BACKGROUND The amygdala is a central node in the brain network that processes aversive emotions and is extensively innervated by dorsal raphe nucleus (DRN) serotonin (5-hydroxytryptamine [5-HT]) neurons. Alterations in DRN 5-HT1A receptor availability cause phenotypes characterized by fearful behavior in preclinical models. However, it is unknown whether 5-HT1A receptor availability is linked specifically to the processing of aversive emotions in humans or whether it modulates connectivity in brain networks involved in emotion processing. To answer this question, we investigated the relationship between DRN 5-HT1A receptor availability and amygdala reactivity to aversive emotion and functional connectivity within the amygdala-cortical network. METHODS We studied 15 healthy human participants who underwent positron emission tomography scanning with [(11)C]CUMI-101, a 5-HT1A partial agonist radioligand, and functional magnetic resonance imaging of brain responses during an incidental emotion processing task including happy, fearful, and neutral faces. Regional estimates of 5-HT1A receptor binding potential (nondisplaceable) were obtained by calculating total volumes of distribution for presynaptic DRN and amygdala. Connectivity between the amygdala and corticolimbic areas was assessed using psychophysiologic interaction analysis with the amygdala as the seed region. RESULTS Analysis of the fear versus neutral contrast revealed a significant negative correlation between amygdala response and DRN binding potential (nondisplaceable) (r = -.87, p < .001). Availability of DRN 5-HT1A receptors positively correlated with amygdala connectivity with middle frontal gyrus, anterior cingulate cortex, bilateral precuneus, and left supramarginal gyrus for fearful (relative to neutral) faces. CONCLUSIONS Our data show that DRN 5-HT1A receptor availability is linked specifically to the processing of aversive emotions in the amygdala and the modulation of amygdala-cortical connectivity.
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Affiliation(s)
- Sudhakar Selvaraj
- Medical Research Council Clinical Sciences Centre, Hammersmith Hospital, London, W12 0NN, UK,Department of Psychiatry and Behavioral Sciences, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Elias Mouchlianitis
- Medical Research Council Clinical Sciences Centre, Hammersmith Hospital, London, W12 0NN, UK
| | - Paul Faulkner
- Institute of Cognitive Neuroscience, University College London, WC1N 3AR, UK
| | | | | | - Jonathan P Roiser
- Institute of Cognitive Neuroscience, University College London, WC1N 3AR, UK
| | - Oliver Howes
- Medical Research Council Clinical Sciences Centre, Hammersmith Hospital, London, W12 0NN, UK,Institute of Psychiatry, King’s College London, SE5 8AF, UK
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20
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Ostock CY, Hallmark J, Palumbo N, Bhide N, Conti M, George JA, Bishop C. Modulation of L-DOPA's antiparkinsonian and dyskinetic effects by α2-noradrenergic receptors within the locus coeruleus. Neuropharmacology 2015; 95:215-25. [PMID: 25817388 DOI: 10.1016/j.neuropharm.2015.03.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 02/12/2015] [Accepted: 03/09/2015] [Indexed: 01/01/2023]
Abstract
Long-term l-DOPA use for Parkinson's disease (PD) is frequently complicated by the emergence of a debilitating motor side effect known as l-DOPA-induced dyskinesia (LID). Accumulating evidence has implicated the norepinephrine (NE) system in the pathogenesis of LID. Here we used the unilateral 6-hydroxydopamine rat model of PD to determine the role of the α2-adrenoceptors (α2R) in l-DOPA's therapeutic and detrimental motor-inducing effects. First, we characterized the effects of systemic α2R stimulation with clonidine, or blockade with atipamezole, on LID using the rodent abnormal involuntary movements scale, and l-DOPA's therapeutic effects using the forepaw adjusting steps test and locomotor activity chambers. The anatomical locus of action of α2R in LID was investigated by directly infusing clonidine or atipamezole into the locus coeruleus prior to systemic l-DOPA administration. Results showed systemic clonidine treatment reduced LID and locomotor activity but did not interfere with l-DOPA's antiparkinsonian benefits. Conversely, systemic atipamezole pretreatment prolonged LID and locomotor activity but did not modulate l-DOPA's antiparkinsonian benefits. Intra-LC infusions of clonidine and atipamezole mirrored systemic effects where clonidine reduced, and atipamezole increased, LID. Collectively, these results demonstrate that α2R play an important modulatory role in l-DOPA-mediated behaviors and should be further investigated as a potential therapeutic target.
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Affiliation(s)
- Corinne Y Ostock
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY, USA
| | - Joy Hallmark
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY, USA
| | - Noel Palumbo
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY, USA
| | - Nirmal Bhide
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY, USA
| | - Melissa Conti
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY, USA
| | - Jessica A George
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY, USA
| | - Christopher Bishop
- Behavioral Neuroscience Program, Department of Psychology, Binghamton University, Binghamton, NY, USA.
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21
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Fischer AG, Jocham G, Ullsperger M. Dual serotonergic signals: a key to understanding paradoxical effects? Trends Cogn Sci 2014; 19:S1364-6613(14)00237-X. [PMID: 25532701 DOI: 10.1016/j.tics.2014.11.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 11/03/2014] [Accepted: 11/04/2014] [Indexed: 01/07/2023]
Abstract
Neuroscientists have been puzzled by the fact that acute administration of a selective serotonin reuptake inhibitor (SSRI) produces results that are, at times, compatible with either decreases or increases in serotonergic neurotransmission. Furthermore, the underlying cause of the delayed onset of antidepressant effects of SSRI treatment has remained obscure. It has recently been reported that serotonergic raphe neurons co-release glutamate and that serotonergic and glutamatergic components constitute a dual signal with behaviorally distinct effects. We discuss the consequences of these novel findings and propose a framework for understanding the controversial effects of acute SSRI administration. Furthermore, we suggest that the delayed remedial onset of SSRI treatment could be explained by an initial reduction of the glutamatergic component of the dual serotonergic signal.
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Affiliation(s)
- Adrian G Fischer
- Otto-von-Guericke University, Institute of Psychology II, Magdeburg, Germany.
| | - Gerhard Jocham
- Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - Markus Ullsperger
- Otto-von-Guericke University, Institute of Psychology II, Magdeburg, Germany; Center for Behavioral Brain Sciences, Magdeburg, Germany; Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands
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22
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Serotonin in anxiety and panic: Contributions of the elevated T-maze. Neurosci Biobehav Rev 2014; 46 Pt 3:397-406. [DOI: 10.1016/j.neubiorev.2014.03.007] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 02/05/2014] [Accepted: 03/03/2014] [Indexed: 11/21/2022]
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23
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Repeated exposure to MDMA triggers long-term plasticity of noradrenergic and serotonergic neurons. Mol Psychiatry 2014; 19:823-33. [PMID: 23958955 DOI: 10.1038/mp.2013.97] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 06/28/2013] [Accepted: 07/10/2013] [Indexed: 11/08/2022]
Abstract
3,4-Methylenedioxymethamphetamine (MDMA or 'ecstasy') is a psychostimulant drug, widely used recreationally among young people in Europe and North America. Although its neurotoxicity has been extensively described, little is known about its ability to strengthen neural circuits when administered in a manner that reproduces human abuse (i.e. repeated exposure to a low dose). C57BL/6J mice were repeatedly injected with MDMA (10 mg kg(-1), intraperitoneally) and studied after a 4-day or a 1-month withdrawal. We show, using in vivo microdialysis and locomotor activity monitoring, that repeated injections of MDMA induce a long-term sensitization of noradrenergic and serotonergic neurons, which correlates with behavioral sensitization. The development of this phenomenon, which lasts for at least 1 month after withdrawal, requires repeated stimulation of α(1B)-adrenergic and 5-hydroxytryptamine (5-HT)(2A) receptors. Moreover, behavioral and neuroendocrine assays indicate that hyper-reactivity of noradrenergic and serotonergic networks is associated with a persistent desensitization of somatodendritic α(2A)-adrenergic and 5-HT1A autoreceptor function. Finally, molecular analysis including radiolabeling, western blot and quantitative reverse transcription-polymerase chain reaction reveals that mice repeatedly treated with MDMA exhibit normal α(2A)-adrenergic and 5-HT(1A) receptor binding, but a long-lasting downregulation of Gαi proteins expression in both locus coeruleus and dorsal raphe nucleus. Altogether, our results show that repeated MDMA exposure causes strong neural and behavioral adaptations and that inhibitory feedback mediated by α(2A)-adrenergic and 5-HT(1A) autoreceptors has an important role in the physiopathology of addictive behaviors.
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24
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Able JA, Liu Y, Jandacek R, Rider T, Tso P, McNamara RK. Omega-3 fatty acid deficient male rats exhibit abnormal behavioral activation in the forced swim test following chronic fluoxetine treatment: association with altered 5-HT1A and alpha2A adrenergic receptor expression. J Psychiatr Res 2014; 50:42-50. [PMID: 24360505 PMCID: PMC3904789 DOI: 10.1016/j.jpsychires.2013.11.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 11/01/2013] [Accepted: 11/20/2013] [Indexed: 12/25/2022]
Abstract
Omega-3 fatty acid deficiency during development leads to enduing alterations in central monoamine neurotransmission in rat brain. Here we investigated the effects of omega-3 fatty acid deficiency on behavioral and neurochemical responses to chronic fluoxetine (FLX) treatment. Male rats were fed diets with (CON, n = 34) or without (DEF, n = 30) the omega-3 fatty acid precursor alpha-linolenic acid (ALA) during peri-adolescent development (P21-P90). A subset of CON (n = 14) and DEF (n = 12) rats were administered FLX (10 mg/kg/d) through their drinking water for 30 d beginning on P60. The forced swimming test (FST) was initiated on P90, and regional brain mRNA markers of serotonin and noradrenaline neurotransmission were determined. Dietary ALA depletion led to significant reductions in frontal cortex docosahexaenoic acid (DHA, 22:6n-3) composition in DEF (-26%, p = 0.0001) and DEF + FLX (-32%, p = 0.0001) rats. Plasma FLX and norfluoxetine concentrations did not different between FLX-treated DEF and CON rats. During the 15-min FST pretest, DEF + FLX rats exhibited significantly greater climbing behavior compared with CON + FLX rats. During the 5-min test trial, FLX treatment reduced immobility and increased swimming in CON and DEF rats, and only DEF + FLX rats exhibited significant elevations in climbing behavior. DEF + FLX rats exhibited greater midbrain, and lower frontal cortex, 5-HT1A mRNA expression compared with all groups including CON + FLX rats. DEF + FLX rats also exhibited greater midbrain alpha2A adrenergic receptor mRNA expression which was positively correlated with climbing behavior in the FST. These preclinical data demonstrate that low omega-3 fatty acid status leads to abnormal behavioral and neurochemical responses to chronic FLX treatment in male rats.
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Affiliation(s)
- Jessica A. Able
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, OH 45267
| | - Yanhong Liu
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, OH 45267
| | - Ronald Jandacek
- Department of Pathology, University of Cincinnati, Cincinnati OH 45237
| | - Therese Rider
- Department of Pathology, University of Cincinnati, Cincinnati OH 45237
| | - Patrick Tso
- Department of Pathology, University of Cincinnati, Cincinnati OH 45237
| | - Robert K. McNamara
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, OH 45267,Corresponding author: Robert K. McNamara, Ph.D. Department of Psychiatry and Behavioral Neuroscience University of Cincinnati College of Medicine 260 Stetson Street Cincinnati, OH 45219-0516 PH: 513-558-5601 FAX: 513-558-4805
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Almeida PVG, Trovo MC, Tokumoto AM, Pereira AC, Padovan CM. Role of serotonin 1A receptors in the median raphe nucleus on the behavioral consequences of forced swim stress. J Psychopharmacol 2013; 27:1134-40. [PMID: 24162801 DOI: 10.1177/0269881113508829] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Despite the intense research on the neurobiology of stress, the role of serotonin (5-HT)1A receptors still remains to be elucidated. In the hippocampus, post-synaptic 5-HT1A receptors activation induces anxiolytic effects in animals previously exposed to stressful situations. However, little is known about somatodendritic 5-HT1A receptors in the median raphe nucleus (MRN). Therefore, the aim of this study was to investigate the role of 5-HT1A receptors located in the MRN in rats exposed to forced swim stress. After recovering from surgery, rats were forced to swim for 15 min in a cylinder. Intra-MRN injections of saline, 8-OH-DPAT (3 nmol/0.2 µL) and/or WAY-100635 (0.3 nmol/0.2 µL) were performed immediately before or after pre-exposure or 24 h later (immediately before test). Non-stressed rats received the same treatment 24 h or 10 min before test. Our data showed that 8-OH-DPAT increased latency to display immobility while decreasing time spent immobile in almost all experimental conditions. These effects were not prevented by previous treatment with WAY-100635. No effects of different treatments were described in non-stressed animals. Taken together, our data suggest that in addition to activation of 5-HT1A, 5-HT7 receptors may also be involved in the behavioural consequences of exposure to swim stress.
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Affiliation(s)
- P V G Almeida
- 1Departamento de Psicologia da Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brasil
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26
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Shim S, El Mansari M, Blier P. Modulation of the Antidepressant-Like Effects of Sustained Administration of Carisbamate and Lamotrigine on Monoaminergic Systems: Electrophysiological Studies in the Rat Brain. J Pharmacol Exp Ther 2013; 347:487-96. [DOI: 10.1124/jpet.113.203315] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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Donaldson ZR, Nautiyal KM, Ahmari SE, Hen R. Genetic approaches for understanding the role of serotonin receptors in mood and behavior. Curr Opin Neurobiol 2013; 23:399-406. [PMID: 23385115 DOI: 10.1016/j.conb.2013.01.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 01/03/2013] [Accepted: 01/13/2013] [Indexed: 01/06/2023]
Abstract
Serotonin (5-hydroxytryptamine; 5-HT) is an ancient signaling molecule that has a conserved role in modulating mood and behavior. Integral to its pleiotropic actions is the existence of multiple receptors, expressed in distinct but often overlapping patterns within the brain and the periphery. The existence of ∼14 mammalian receptor subtypes, many of which possess similar pharmacological profiles, has made assigning functional roles for these receptors challenging. This challenge has been further compounded by the revelation that a single receptor can have several different functions depending upon where and when it is expressed and activated, that is, in brain versus periphery, or at different developmental time points. This review highlights the contribution of genetic techniques to dissect the specific function of distinct serotonin receptor populations across the life course, with an emphasis on the contribution of different serotonin 1A receptor populations to mood and behavior. Similar approaches hold the promise to elucidate the functional roles of other receptors, as well as the interaction of serotonin with other neuroendocrine modulators of mood and behavior.
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Affiliation(s)
- Zoe R Donaldson
- Departments of Psychiatry and Neuroscience, Columbia University, New York, NY 10032, USA.
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Albert PR. Transcriptional regulation of the 5-HT1A receptor: implications for mental illness. Philos Trans R Soc Lond B Biol Sci 2012; 367:2402-15. [PMID: 22826341 DOI: 10.1098/rstb.2011.0376] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The serotonin-1A (5-HT(1A)) receptor is an abundant post-synaptic 5-HT receptor (heteroreceptor) implicated in regulation of mood, emotion and stress responses and is the major somatodendritic autoreceptor that negatively regulates 5-HT neuronal activity. Based on animal models, an integrated model for opposing roles of pre- and post-synaptic 5-HT(1A) receptors in anxiety and depression phenotypes and response to antidepressants is proposed. Understanding differential transcriptional regulation of pre- versus post-synaptic 5-HT(1A) receptors could provide better tools for their selective regulation. This review examines the transcription factors that regulate brain region-specific basal and stress-induced expression of the 5-HT(1A) receptor gene (Htr1a). A functional polymorphism, rs6295 in the Htr1a promoter region, blocks the function of specific repressors Hes1, Hes5 and Deaf1, resulting in increased 5-HT(1A) autoreceptor expression in animal models and humans. Its association with altered 5-HT(1A) expression, depression, anxiety and antidepressant response are related to genotype frequency in different populations, sample homogeneity, disease outcome measures and severity. Preliminary evidence from gene × environment studies suggests the potential for synergistic interaction of stress-mediated repression of 5-HT(1A) heteroreceptors, and rs6295-induced upregulation of 5-HT(1A) autoreceptors. Targeted therapeutics to inhibit 5-HT(1A) autoreceptor expression and induce 5-HT(1A) heteroreceptor expression may ameliorate treatment of anxiety and major depression.
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Affiliation(s)
- Paul R Albert
- Ottawa Hospital Research Institute (Neuroscience), University of Ottawa, , 451 Smyth Road, Ottawa, ON, Canada , K1H 8M5.
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Domínguez-López S, Mahar I, Bambico FR, Labonté B, Ochoa-Sánchez R, Leyton M, Gobbi G. Short-term effects of melatonin and pinealectomy on serotonergic neuronal activity across the light-dark cycle. J Psychopharmacol 2012; 26:830-44. [PMID: 21730015 DOI: 10.1177/0269881111408460] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Melatonin (MLT) and serotonin (5-HT) are two biosynthetically related compounds implicated in several common physiological functions and the etiology of mood disorders. How they interact, though, is not yet fully understood. In this study, single-unit extracellular recordings were used to monitor dorsal raphe nucleus (DR) 5-HT neuronal activity in anesthetized rats, under basal conditions (CTRL), in response to MLT administration, and after pinealectomy (PX) across the light-dark cycle. Under basal conditions, the number of spontaneously active 5-HT neurons and their firing rate were both significantly lower in the dark phase. In the light phase, administration of MLT at low doses (0.5-1 mg/kg, i.v.) decreased 5-HT firing activity. This inhibitory effect of MLT was completely blocked by the MT₁/MT₂ receptor antagonist luzindole, but not by the selective MT(2) receptor antagonist 4P-PDOT, the selective 5-HT(1A) receptor antagonist WAY100635, or by the α₂ adrenoceptor antagonist idazoxan. In the opposite experiment, PX increased 5-HT firing activity in the dark phase, and this was reversed by MLT administration (1 mg/kg, i.v.). Finally, in a forced swim test, MLT (1 mg/kg, i.p.) increased immobility time and decreased swimming behavior. Together, these results suggest that nocturnal MLT secretion imposes tonic inhibitory control over a sub-population of DR 5-HT neurons. This MLT-induced decrease in 5-HT neurotransmission may represent a biological mechanism underlying mood disorders characterized by increased MLT secretion, such as seasonal affective disorder.
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Affiliation(s)
- Sergio Domínguez-López
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montreal, QC, Canada
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Serotonin-1A autoreceptors are necessary and sufficient for the normal formation of circuits underlying innate anxiety. J Neurosci 2011; 31:6008-18. [PMID: 21508226 DOI: 10.1523/jneurosci.5836-10.2011] [Citation(s) in RCA: 146] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Identifying the factors contributing to the etiology of anxiety and depression is critical for the development of more efficacious therapies. Serotonin (5-HT) is intimately linked to both disorders. The inhibitory serotonin-1A (5-HT(1A)) receptor exists in two separate populations with distinct effects on serotonergic signaling: (1) an autoreceptor that limits 5-HT release throughout the brain and (2) a heteroreceptor that mediates inhibitory responses to released 5-HT. Traditional pharmacologic and transgenic strategies have not addressed the distinct roles of these two receptor populations. Here we use a recently developed genetic mouse system to independently manipulate 5-HT(1A) autoreceptor and heteroreceptor populations. We show that 5-HT(1A) autoreceptors act to affect anxiety-like behavior. In contrast, 5-HT(1A) heteroreceptors affect responses to forced swim stress, without effects on anxiety-like behavior. Together with our previously reported work, these results establish distinct roles for the two receptor populations, providing evidence that signaling through endogenous 5-HT(1A) autoreceptors is necessary and sufficient for the establishment of normal anxiety-like behavior.
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Dao JM, McQuown SC, Loughlin SE, Belluzzi JD, Leslie FM. Nicotine alters limbic function in adolescent rat by a 5-HT1A receptor mechanism. Neuropsychopharmacology 2011; 36:1319-31. [PMID: 21412223 PMCID: PMC3096821 DOI: 10.1038/npp.2011.8] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Epidemiological studies have shown that adolescent smoking is associated with health risk behaviors, including high-risk sexual activity and illicit drug use. Using rat as an animal model, we evaluated the behavioral and biochemical effects of a 4-day, low-dose nicotine pretreatment (60 μg/kg; intravenous) during adolescence and adulthood. Nicotine pretreatment significantly increased initial acquisition of cocaine self-administration, quinpirole-induced locomotor activity, and penile erection in adolescent rats, aged postnatal day (P)32. These effects were long lasting, remaining evident 10 days after the last nicotine treatment, and were observed when nicotine pretreatment was administered during early adolescence (P28-31), but not late adolescence (P38-41) or adulthood (P86-89). Neurochemical analyses of c-fos mRNA expression, and of monoamine transmitter and transporter levels, showed that forebrain limbic systems are continuing to develop during early adolescence, and that this maturation is critically altered by brief nicotine exposure. Nicotine selectively increased c-fos mRNA expression in the nucleus accumbens shell and basolateral amygdala in adolescent, but not adult animals, and altered serotonin markers in these regions as well as the prefrontal cortex. Nicotine enhancement of cocaine self-administration and quinpirole-induced locomotor activity was blocked by co-administration of WAY 100 635 (N-{2-[4-(2-methoxyphenyl)-1-piperazinyl] ethyl}-N-(2-pyridinyl)cyclohexanecarboxamide), a selective serotonin 1A (5-HT1A) receptor antagonist. Early adolescent pretreatment with the mixed autoreceptor/heteroceptor 5-HT1A receptor agonist, 8-OH-DPAT, but not the autoreceptor-selective agonist, S-15535, also enhanced quinpirole-induced locomotor activation. Nicotine enhancement of quinpirole-induced penile erection was not blocked by WAY 100 635 nor mimicked by 8-OH-DPAT. These findings indicate that early adolescent nicotine exposure uniquely alters limbic function by both 5-HT1A and non-5-HT1A receptor mechanisms.
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Affiliation(s)
- Jasmin M Dao
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA 92697-3800, USA.
| | - Susan C McQuown
- Department of Pharmacology, School of Medicine, University of California, Irvine, CA, USA
| | - Sandra E Loughlin
- Department of Pharmacology, School of Medicine, University of California, Irvine, CA, USA
| | - James D Belluzzi
- Department of Pharmacology, School of Medicine, University of California, Irvine, CA, USA
| | - Frances M Leslie
- Department of Anatomy and Neurobiology, School of Medicine, University of California, Irvine, CA, USA,Department of Pharmacology, School of Medicine, University of California, Irvine, CA, USA
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32
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Pobbe RLH, Zangrossi H, Blanchard DC, Blanchard RJ. Involvement of dorsal raphe nucleus and dorsal periaqueductal gray 5-HT receptors in the modulation of mouse defensive behaviors. Eur Neuropsychopharmacol 2011; 21:306-15. [PMID: 20570114 PMCID: PMC3250220 DOI: 10.1016/j.euroneuro.2010.05.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 03/26/2010] [Accepted: 05/04/2010] [Indexed: 11/17/2022]
Abstract
Previous findings point to the involvement of the dorsal raphe nucleus (DRN) and dorsal periaqueductal gray (dPAG) serotonergic receptors in the mediation of defensive responses that are associated with specific subtypes of anxiety disorders. These studies have mostly been conducted with rats tested in the elevated T-maze, an experimental model of anxiety that was developed to allow the measurement, in the same animal, of two behaviors mentioned: inhibitory avoidance and one-way escape. Such behavioral responses have been respectively related to generalized anxiety disorder (GAD) and panic disorder (PD). In order to assess the generality of these findings, in the current study we investigated the effects of the injection of 5-HT-related drugs into the DRN and dPAG of another rodent species, mouse, on the mouse defense test battery (MDTB), a test of a range of defensive behaviors to an unconditioned threat, a predator. Male CD-1 mice were tested in the MDTB after intra-DRN administration of the 5-HT(1A) receptor antagonist WAY-100635 or after intra-dPAG injection of two serotonergic agonists, the 5-HT(1A) receptor agonist 8-OH-DPAT and the 5-HT(2A/2C) receptor agonist DOI. Intra-DRN injection of WAY-100635 did not change behavioral responses of mice confronted with a rat in the MDTB. In the dPAG, both 8-OH-DPAT and DOI consistently impaired mouse escape behavior assessed in the MDTB. Intra-dPAG infusion of 8-OH-DPAT also decreased measures of mouse risk assessment in the rat exposure test. In conclusion, the current findings are in partial agreement with previous results obtained with rats tested in the elevated T-maze. Although there is a high level of similarity between the behavioral effects obtained in rats (elevated T-maze) and mice (MDTB and RET) with the infusion of 5-HT agonists into the dPAG, the same is not true regarding the effects of blockade of DRN 5-HT(1A) receptors in these rodent species. These data suggest that there may be differences between mice and rats regarding the involvement of the DRN in the mediation of defensive behaviors.
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MESH Headings
- Animals
- Anxiety Disorders/metabolism
- Behavior, Animal/drug effects
- Escape Reaction/drug effects
- Immobility Response, Tonic/drug effects
- Infusions, Intraventricular
- Male
- Mice
- Nerve Tissue Proteins/agonists
- Nerve Tissue Proteins/antagonists & inhibitors
- Nerve Tissue Proteins/physiology
- Neurons/drug effects
- Panic Disorder/metabolism
- Periaqueductal Gray/drug effects
- Raphe Nuclei/drug effects
- Receptor, Serotonin, 5-HT1A/physiology
- Receptor, Serotonin, 5-HT2A/physiology
- Receptor, Serotonin, 5-HT2C/physiology
- Receptors, Serotonin/physiology
- Serotonin 5-HT1 Receptor Agonists/administration & dosage
- Serotonin 5-HT1 Receptor Agonists/pharmacology
- Serotonin 5-HT1 Receptor Antagonists/administration & dosage
- Serotonin 5-HT1 Receptor Antagonists/pharmacology
- Serotonin 5-HT2 Receptor Agonists/administration & dosage
- Serotonin 5-HT2 Receptor Agonists/pharmacology
- Species Specificity
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Affiliation(s)
- Roger L H Pobbe
- Pacific Biosciences Research Center, University of Hawaii, 1993 East-West Road, Honolulu, HI 96822, USA.
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33
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Locus coeruleus and dorsal raphe neuron activity and response to acute antidepressant administration in a rat model of Parkinson's disease. Int J Neuropsychopharmacol 2011; 14:187-200. [PMID: 20426885 DOI: 10.1017/s146114571000043x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
In addition to noradrenergic and serotonergic systems, dopaminergic neurotransmission seems to play an important role in the aetiopathogenesis of, and recovery from, depression. Moreover, the incidence of depression is higher in patients affected by diseases where the dopaminergic system is highly impaired, such us Parkinson's disease. Here, we investigated the effects of dopamine degeneration on the activity and response to antidepressants of locus coeruleus (LC) noradrenergic and dorsal raphe nucleus (DRN) serotonergic neurons. To this end, single-unit extracellular recordings were performed in control and 6-hydroxydopamine (6-OHDA)-lesioned animals. In this latter group, LC neurons showed a lower basal firing rate as well as less sensitivity to the administration of the serotonin reuptake inhibitor, fluoxetine. The rest of electrophysiological parameters and the response to the administration of the α2-adrenoceptor agonist, clonidine and the noradrenaline reuptake inhibitor, reboxetine remained unaltered. In the DRN, dopamine depletion did not modify the basal electrophysiological characteristics and the response to clonidine or fluoxetine administration. In contrast, the administration of reboxetine more efficiently induced an inhibitory effect in the lesioned group. In additional analyses it was observed that while in control animals, LC and DRN basal firing rate was significantly correlated, this relationship was lost after the 6-OHDA lesion. In conclusion, dopaminergic degeneration alters LC neuron basal activity, the relationship/synteny between both nuclei, and their response to antidepressants. These findings shed fresh light on our understanding of the role of dopamine in depression and the mechanism action of antidepressants.
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Characterization of the electrophysiological properties of triple reuptake inhibitors on monoaminergic neurons. Int J Neuropsychopharmacol 2011; 14:211-23. [PMID: 20149268 DOI: 10.1017/s1461145710000076] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Triple reuptake inhibitors represent a potential new class of antidepressant drugs that block norepinephrine (NE), dopamine (DA) and serotonin [5-hydroxytryptamine (5-HT)] transporters. The present in-vivo electrophysiological study was undertaken to determine the effects of the triple reuptake inhibitors SEP-225289 and DOV216303 on the neuronal activities of locus coeruleus (LC) NE, ventral tegmental area (VTA) DA and dorsal raphe (DR) 5-HT neurons. Administered acutely, SEP-225289 and DOV216303 dose-dependently decreased the spontaneous firing rate of LC NE, VTA DA and DR 5-HT neurons through the activation of α₂, D₂ and 5-HT(₁A) autoreceptors, respectively. Both compounds predominantly inhibited the firing rate of LC NE neurons while producing only a partial decrease in VTA DA and DR 5-HT neuronal discharge. SEP-225289 was equipotent at inhibiting 5-HT and NE transporters since it prolonged to the same extent the time required for a 50% recovery (RT₅₀) of the firing activity of dorsal hippocampus CA3 pyramidal neurons from the inhibition induced by microiontophoretic application of 5-HT and NE. Finally, in the presence of WAY100635, a 5-HT(₁A) receptor antagonist, SEP-225289 activated 5-HT neurons at doses that normally did not inhibit them. Taken together, the present results indicate that reciprocal interactions among NE, DA and 5-HT inputs need to be considered to anticipate the net effect of triple reuptake inhibitors on the enhancement of brain monoamine transmission. The results also suggest that the therapeutic action of triple reuptake inhibitors may be potentiated by antagonizing the cell body 5-HT(₁A) autoreceptors.
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Miguel TLB, Pobbe RLH, Spiacci A, Zangrossi H. Dorsal raphe nucleus regulation of a panic-like defensive behavior evoked by chemical stimulation of the rat dorsal periaqueductal gray matter. Behav Brain Res 2010; 213:195-200. [DOI: 10.1016/j.bbr.2010.04.055] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Revised: 04/26/2010] [Accepted: 04/29/2010] [Indexed: 11/24/2022]
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Ghanbari R, El Mansari M, Blier P. Sustained administration of trazodone enhances serotonergic neurotransmission: in vivo electrophysiological study in the rat brain. J Pharmacol Exp Ther 2010; 335:197-206. [PMID: 20647493 DOI: 10.1124/jpet.110.169417] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Despite its clinical use for more than two decades, the mechanisms by which trazodone acts as an antidepressant are not clear, because it has affinity for a variety of 5-hydroxytryptamine (5-HT; serotonin) receptors and the 5-HT transporter. This study examined the effects of sustained trazodone administration on 5-HT neurotransmission. Electrophysiological recordings were conducted in anesthetized rats. Subcutaneously implanted minipumps delivered vehicle or trazodone (10 mg/kg/day) for 2 and 14 days. A 2-day trazodone administration suppressed the firing rate of raphe 5-HT neurons, which recovered to baseline after 14 days. This was attributable to 5-HT(1A) autoreceptor desensitization because the suppressant effect of the 5-HT autoreceptor agonist lysergic acid diethylamide was dampened in 14-day trazodone-treated rats. Prolonged trazodone administration did not change the sensitivity of postsynaptic 5-HT(1A) and α(2)-adrenergic receptors in hippocampus, but enhanced synaptic 5-HT levels because the 5-HT(1A) antagonist N-{2-[4 (2-methoxyphenyl)-1-piperazinyl]ethyl}-N-(2-pyridinyl) cyclohexanecarboxamide trihydrochloride (WAY-100635) enhanced hippocampal firing in treated rats, but not in controls. Trazodone administration for 14 days increased the 50% recovery time value, an index of 5-HT transporter blockade in vivo, and decreased the inhibitory function of terminal 5-HT(1B) autoreceptors on the electrically evoked release of 5-HT. The agonistic action of trazodone at 5-HT(1A) receptors was characterized as being full because it did not attenuate the inhibitory action of 5-HT when coapplied locally. The enhanced 5-HT neurotransmission by trazodone is caused in part by reuptake blockade and activation of postsynaptic 5-HT(1A) receptors, which may account for its effectiveness in major depression.
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Affiliation(s)
- Ramez Ghanbari
- University of Ottawa Institute of Mental Health Research, Ottawa, ON, Canada.
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Ferdyn-Drosik M, Nowak P, Bojanek K, Bałasz M, Kasperski J, Skaba D, Muchacki R, Kostrzewa RM. Neonatal DSP-4 treatment impairs 5-HT1B receptor reactivity in adult rats. Behavioral and biochemical studies. Pharmacol Rep 2010; 62:608-20. [DOI: 10.1016/s1734-1140(10)70318-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Revised: 11/19/2009] [Indexed: 10/25/2022]
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Rotllant D, Márquez C, Nadal R, Armario A. The brain pattern of c-fos induction by two doses of amphetamine suggests different brain processing pathways and minor contribution of behavioural traits. Neuroscience 2010; 168:691-705. [DOI: 10.1016/j.neuroscience.2010.04.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Revised: 04/08/2010] [Accepted: 04/11/2010] [Indexed: 11/29/2022]
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Hildebrandt T, Alfano L, Tricamo M, Pfaff DW. Conceptualizing the role of estrogens and serotonin in the development and maintenance of bulimia nervosa. Clin Psychol Rev 2010; 30:655-68. [PMID: 20554102 DOI: 10.1016/j.cpr.2010.04.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Revised: 04/24/2010] [Accepted: 04/29/2010] [Indexed: 10/19/2022]
Abstract
Serotonergic dysregulation is thought to underlie much of the pathology in bulimia nervosa (BN). The purpose of this review is to expand the serotonergic model by incorporating specific and nonspecific contributions of estrogens to the development and maintenance of bulimic pathology in order to guide research from molecular genetics to novel therapeutics for BN. Special emphasis is given to the organizing theory of general brain arousal which allows for integration of specific and nonspecific effects of these systems on behavioral endpoints such as binge eating or purging as well as arousal states such as fear, novelty seeking, or sex. Regulation of the serotonergic system by estrogens is explored, and genetic, epigenetic, and environmental estrogen effects on bulimic pathology and risk factors are discussed. Genetic and neuroscientific research support this two-system conceptualization of BN with both contributions to the developmental and maintenance of the disorder. Implications of an estrogenic-serotonergic model of BN are discussed as well as guidelines and suggestions for future research and novel therapeutic targets.
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Affiliation(s)
- Tom Hildebrandt
- Eating and Weight Disorders Program, Mount Sinai School of Medicine, One Gustave L. Levy Place, Box 1230, New York, NY 10029, USA.
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Lucas G, Du J, Romeas T, Mnie-Filali O, Haddjeri N, Piñeyro G, Debonnel G. Selective serotonin reuptake inhibitors potentiate the rapid antidepressant-like effects of serotonin4 receptor agonists in the rat. PLoS One 2010; 5:e9253. [PMID: 20169084 PMCID: PMC2821932 DOI: 10.1371/journal.pone.0009253] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Accepted: 01/09/2010] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND We have recently reported that serotonin(4) (5-HT(4)) receptor agonists have a promising potential as fast-acting antidepressants. Here, we assess the extent to which this property may be optimized by the concomitant use of conventional antidepressants. METHODOLOGY/PRINCIPAL FINDINGS We found that, in acute conditions, the 5-HT(4) agonist prucalopride was able to counteract the inhibitory effect of the selective serotonin reuptake inhibitors (SSRI) fluvoxamine and citalopram on 5-HT neuron impulse flow, in Dorsal Raphé Nucleus (DRN) cells selected for their high (>1.8 Hz) basal discharge. The co-administration of both prucalopride and RS 67333 with citalopram for 3 days elicited an enhancement of DRN 5-HT neuron average firing rate, very similar to what was observed with either 5-HT(4) agonist alone. At the postsynaptic level, this translated into the manifestation of a tonus on hippocampal postsynaptic 5-HT(1A) receptors, that was two to three times stronger when the 5-HT(4) agonist was combined with citalopram. Similarly, co-administration of citalopram synergistically potentiated the enhancing effect of RS 67333 on CREB protein phosphorylation within the hippocampus. Finally, in the Forced Swimming Test, the combination of RS 67333 with various SSRIs (fluvoxamine, citalopram and fluoxetine) was more effective to reduce time of immobility than the separate administration of each compound. CONCLUSIONS/SIGNIFICANCE These findings strongly suggest that the adjunction of an SSRI to a 5-HT(4) agonist may help to optimize the fast-acting antidepressant efficacy of the latter.
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Affiliation(s)
- Guillaume Lucas
- Department of Psychiatry, Centre de Recherche Fernand Seguin, Université de Montréal, Montréal, Québec, Canada.
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Bambico FR, Nguyen NT, Katz N, Gobbi G. Chronic exposure to cannabinoids during adolescence but not during adulthood impairs emotional behaviour and monoaminergic neurotransmission. Neurobiol Dis 2009; 37:641-55. [PMID: 19969082 DOI: 10.1016/j.nbd.2009.11.020] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 11/21/2009] [Accepted: 11/26/2009] [Indexed: 12/27/2022] Open
Abstract
The pathophysiological neural mechanism underlying the depressogenic and anxiogenic effects of chronic adolescent cannabinoid use may be linked to perturbations in monoaminergic neurotransmission. We tested this hypothesis by administering the CB(1) receptor agonist WIN55,212-2, once daily for 20 days to adolescent and adult rats, subsequently subjecting them to tests for emotional reactivity paralleled by the in vivo extracellular recordings of serotonergic and noradrenergic neurons. Chronic adolescent exposure but not adult exposure to low (0.2 mg/kg) and high (1.0 mg/kg) doses led to depression-like behaviour in the forced swim and sucrose preference test, while the high dose also induced anxiety-like consequences in the novelty-suppressed feeding test. Electrophysiological recordings revealed both doses to have attenuated serotonergic activity, while the high dose also led to a hyperactivity of noradrenergic neurons only after adolescent exposure. These suggest that long-term exposure to cannabinoids during adolescence induces anxiety-like and depression-like behaviours in adulthood and that this may be instigated by serotonergic hypoactivity and noradrenergic hyperactivity.
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Affiliation(s)
- Francis Rodriguez Bambico
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, 1033 Pine Avenue West, Montreal, Canada H3A1A1
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Ghanbari R, El Mansari M, Shahid M, Blier P. Electrophysiological characterization of the effects of asenapine at 5-HT(1A), 5-HT(2A), alpha(2)-adrenergic and D(2) receptors in the rat brain. Eur Neuropsychopharmacol 2009; 19:177-87. [PMID: 19116183 DOI: 10.1016/j.euroneuro.2008.11.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Revised: 09/23/2008] [Accepted: 11/04/2008] [Indexed: 10/21/2022]
Abstract
Asenapine is a psychopharmacologic agent being developed for schizophrenia and bipolar disorder. This study electrophysiologically characterized the in vivo effects of asenapine at dorsal raphe nucleus (DRN) and hippocampus serotonin-1A (5-HT(1A)), ventral tegmental area D(2), locus coeruleus 5-HT(2A,) and alpha(2)-adrenergic receptors in anesthetized rats. Asenapine displayed potent antagonistic activity at alpha(2)-adrenoceptors (ED(50), 85+/-2 microg/kg), 5-HT(2A) (ED(50), 75+/-2 microg/kg) and D(2) receptors (ED(50), 40+/-2 microg/kg) as evidenced by its reversal of clonidine-, DOI-, and apomorphine-induced inhibition of norepinephrine and dopamine neurons. In contrast, asenapine acted as a partial agonist at 5-HT(1A) receptors in DRN and hippocampus, as indicated by blockade of its inhibitory effect on neuronal firing by the 5-HT(1A) antagonist WAY 100635 and the partial inhibition of the suppressant action of 5-HT when co-applied by microiontophoresis. These results confirm that asenapine displays potent antagonistic activity at 5-HT(2A), D(2), alpha(2)-adrenergic receptors and provide evidence to support its 5-HT(1A) partial agonistic activity.
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Affiliation(s)
- Ramez Ghanbari
- University of Ottawa Institute of Mental Health Research, 1145 Carling Avenue, Ottawa, Ontario K1Z7K4, Canada.
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Boyce-Rustay JM, Palachick B, Hefner K, Chen YC, Karlsson RM, Millstein RA, Harvey-White J, Holmes A. Desipramine potentiation of the acute depressant effects of ethanol: modulation by alpha2-adrenoreceptors and stress. Neuropharmacology 2008; 55:803-11. [PMID: 18625256 PMCID: PMC2632577 DOI: 10.1016/j.neuropharm.2008.06.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2007] [Revised: 05/15/2008] [Accepted: 06/18/2008] [Indexed: 12/15/2022]
Abstract
Ethanol exerts effects on the brain noradrenergic system, and these are thought to contribute to the sedative/hypnotic (depressant) effects of ethanol. Recent studies suggest that the norepinephrine transporter (NET) plays an important role in modulating ethanol's depressant effects. The aim of the present study was to further characterize this role. Transporter blockers with varying affinity for NET versus the serotonin transporter (desipramine>fluoxetine>citalopram) were tested for their ability to alter ethanol's depressant effects, and for comparison, hypothermic effects. Effects of desipramine on another depressant, pentobarbital, were examined. Desipramine potentiation of ethanol's depressant effects was assessed following depletion of brain norepinephrine via N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride (DSP-4) treatment, or depletion of brain 5-HT via para-chlorophenylalanine methyl ester hydrochloride (PCPA) treatment. The effects of co-administration of either the selective alpha2-adrenoreceptor agonist (dexmedetomidine) or the selective alpha2-adrenoreceptor antagonist (atipamezole) on desipramine's effect on ethanol's depressant effects were examined. Given the close link between stress, ethanol and norepinephrine, desipramine potentiation of ethanol's depressant effects was tested following repeated forced swim stress. Results showed that desipramine, but not SERT-selective doses of citalopram or fluoxetine, strongly potentiated the depressant (not hypothermic) effects of ethanol. These effects were mimicked by dexmedetomidine and blocked by atipamezole, but not by depletion of either norepinephrine or 5-HT. Desipramine potentiation of ethanol's depressant effects was abolished following repeated stress. Present findings further support a major role for NET and the alpha2-adrenoreceptor in modulating the depressant effects of ethanol, with possible implications for understanding the role of noradrenergic dysfunction in stress-related alcoholism.
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Affiliation(s)
- Janel M Boyce-Rustay
- Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, MD, USA.
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Audero E, Coppi E, Mlinar B, Rossetti T, Caprioli A, Banchaabouchi MA, Corradetti R, Gross C. Sporadic autonomic dysregulation and death associated with excessive serotonin autoinhibition. Science 2008; 321:130-3. [PMID: 18599790 DOI: 10.1126/science.1157871] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Sudden infant death syndrome is the leading cause of death in the postneonatal period in developed countries. Postmortem studies show alterations in serotonin neurons in the brainstem of such infants. However, the mechanism by which altered serotonin homeostasis might cause sudden death is unknown. We investigated the consequences of altering the autoinhibitory capacity of serotonin neurons with the reversible overexpression of serotonin 1A autoreceptors in transgenic mice. Overexpressing mice exhibited sporadic bradycardia and hypothermia that occurred during a limited developmental period and frequently progressed to death. Moreover, overexpressing mice failed to activate autonomic target organs in response to environmental challenges. These findings show that excessive serotonin autoinhibition is a risk factor for catastrophic autonomic dysregulation and provide a mechanism for a role of altered serotonin homeostasis in sudden infant death syndrome.
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Affiliation(s)
- Enrica Audero
- Mouse Biology Unit, European Molecular Biology Laboratory (EMBL), Via Ramarini 32, 00015 Monterotondo, Italy
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Alpha-Ca2+/calmodulin-dependent protein kinase II contributes to the developmental programming of anxiety in serotonin receptor 1A knock-out mice. J Neurosci 2008; 28:6250-7. [PMID: 18550767 DOI: 10.1523/jneurosci.5219-07.2008] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Mice lacking the serotonin receptor 1A [Htr1aknock-out (Htr1a(KO))] display increased innate and conditioned anxiety-related behavior. Expression of the receptor in the mouse forebrain during development is sufficient to restore normal anxiety-related behavior to knock-out mice, demonstrating a role for serotonin in the developmental programming of anxiety circuits. However, the precise developmental period as well as the signaling pathways and neural substrates involved in this phenomenon are unknown. Here, we show that pharmacological blockade of the receptor from postnatal day 13 (P13)-P34 is sufficient to reproduce the knock-out phenotype in adulthood, thus defining a role for serotonin in the maturation and refinement of anxiety circuits during a limited postnatal period. Furthermore, we identify increases in the phosphorylation of alpha-Ca(2+)/calmodulin-dependent protein kinase II (alphaCaMKII) at threonine 286 in the hippocampus of young Htr1a(KO) mice under anxiety-provoking conditions. Increases in alphaCaMKII phosphorylation were most pronounced in the CA1 region of the hippocampus and were localized to the extrasynaptic compartment, consistent with a tissue-specific effect of the receptor. No changes in alphaCaMKII phosphorylation were found in adult knock-out mice, suggesting a transient role of alphaCaMKII as a downstream target of the receptor. Finally, the anxiety phenotype was abolished when knock-out mice were crossed to mice in which alphaCaMKII phosphorylation was compromised by the heterozygous mutation of threonine 286 into alanine. These findings suggest that modulation of alphaCaMKII function by serotonin during a restricted postnatal period contributes to the developmental programming of anxiety-related behavior.
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Commons KG. Evidence for topographically organized endogenous 5-HT-1A receptor-dependent feedback inhibition of the ascending serotonin system. Eur J Neurosci 2008; 27:2611-8. [PMID: 18513318 DOI: 10.1111/j.1460-9568.2008.06235.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Raphe and extra-raphe 5-HT-1A receptors contribute to feedback inhibition of serotonin (5-HT) neurons; however, the endogenous function of 5-HT-1A receptor-dependent feedback inhibition remains poorly understood. Here, the possibility that 5-HT-1A-mediated feedback inhibition of the raphe nuclei is topographically organized was examined. This was done by testing the effect of systemic blockade of 5-HT-1A receptors on Fos expression in 5-HT neurons in the dorsal raphe (DR) and median raphe (MR). The premise was that appearance of Fos after 5-HT-1A receptor blockade would implicate endogenous inhibition via 5-HT-1A-dependent processes. 5-HT-1A receptor antagonist administration (WAY-100635) in rats returned to their home cage significantly increased the number of Fos-containing 5-HT cells in the lateral wings and the ventral caudal part of the DR as compared to vehicle-injected controls, suggesting that tonic activity of brain 5-HT-1A receptors impacts on these regions. In rats receiving vehicle injections, swim, a behavior known to influence 5-HT neurotransmission, increased the number of Fos-containing 5-HT cells only in the caudal third of DR. Administration of WAY-100635 preceding a swim did not change the amount of Fos in the caudal DR, but increased the number of Fos-containing 5-HT cells in the rostral DR, lateral wings of the DR, and MR. These results confirm, using an imaging approach, that 5-HT-1A receptor-dependent feedback inhibition depends on behavioral state (return to home cage vs. swim). Moreover, they reveal that the effect of 5-HT-1A receptor blockade in each case is subregionally organized.
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Affiliation(s)
- Kathryn G Commons
- Department of Anesthesiology, Perioperative, and Pain Medicine, Children's Hospital, Boston, MA 02115, USA.
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Dos Santos L, de Andrade TGCS, Zangrossi Junior H. 5-HT1A receptors in the dorsal hippocampus mediate the anxiogenic effect induced by the stimulation of 5-HT neurons in the median raphe nucleus. Eur Neuropsychopharmacol 2008; 18:286-94. [PMID: 17728111 DOI: 10.1016/j.euroneuro.2007.07.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Revised: 05/22/2007] [Accepted: 07/18/2007] [Indexed: 12/29/2022]
Abstract
We evaluated the involvement of dorsal hippocampus (DH) 5-HT1A receptors in the mediation of the behavioral effects caused by the pharmacological manipulation of 5-HT neurons in the median raphe nucleus (MRN). To this end, we used the rat elevated T-maze test of anxiety. The results showed that intra-DH injection of the 5-HT1A/7 agonist 8-OH-DPAT facilitated inhibitory avoidance, an anxiogenic effect, without affecting escape. Microinjection of the 5-HT1A antagonist WAY-100635 was ineffective. In the elevated T-maze, inhibitory avoidance and escape have been related to generalized anxiety and panic disorders, respectively. Intra-MRN administration of the excitatory amino acid kainic acid, which non-selectively stimulates 5-HT neurons in this brain area facilitated inhibitory avoidance and impaired escape performance, but also affected locomotion. Intra-MRN injection of WAY-100635, which has a disinhibitory effect on the activity of 5-HT neurons in this midbrain area, only facilitated inhibitory avoidance. Pre-administration of WAY-100635 into the DH blocked the behavioral effect of intra-MRN injection of WAY-100635, but not of kainic acid. These results indicate that DH 5-HT1A receptors mediate the anxiogenic effect induced by the selective stimulation of 5-HT neurons in the MRN.
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Affiliation(s)
- Lucinéia Dos Santos
- Department of Psychology and Education, FFCLRP, University of São Paulo, 14040-901, Ribeirão Preto-SP, Brazil
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The selective 5-HT1A receptor antagonist WAY-100635 inhibits neuronal activity of the ventromedial prefrontal cortex in a rodent model of Parkinson's disease. Neurosci Bull 2008; 23:315-22. [PMID: 18064060 DOI: 10.1007/s12264-007-0047-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVE The ventral part of the medial prefrontal cortex (mPFC) plays an important role in initiation and control of voluntary movement, mood and cognition. However, after the degeneration of the nigrostriatal pathway, the neuronal activity of the ventral mPFC and the role of serotonin(1A) (5-hydroxytryptamine, 5-HT(1A)) receptors in the firing of the neurons are still unknown. The present study is to investigate the change of neuronal activity in the ventral mPFC and the effect of systemic administration of the selective 5-HT(1A) receptor antagonist WAY-100635 on the activity of the neurons in normal and 6-hydroxydopamine (6-OHDA)-lesioned rats. METHODS Single unit responses were recorded extracellularly with glass microelectrodes from ventral mPFC neurons in normal rats and 6-OHDA unilaterally lesioned rats in vivo. RESULTS 6-OHDA lesion of the substantia nigra pars compacta (SNc) significantly increased the firing rate with no change in the firing pattern of neurons of the ventral mPFC in rats. Systemic administration of WAY-100635 (0.1 mg/kg, i.v.) did not change the mean firing rate and firing pattern of ventral mPFC neurons in normal rats. In contrast, WAY-100635 significantly decreased the mean firing rate of the neurons in rats with 6-OHDA lesion of the SNc. CONCLUSION These data suggest that the degeneration of the nigrostriatal pathway results in an increase of neuronal activity of ventral mPFC and dysfunction of 5-HT(1A) receptor.
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Brown JW, Sirlin EA, Benoit AM, Hoffman JM, Darnall RA. Activation of 5-HT1A receptors in medullary raphé disrupts sleep and decreases shivering during cooling in the conscious piglet. Am J Physiol Regul Integr Comp Physiol 2008; 294:R884-94. [DOI: 10.1152/ajpregu.00655.2007] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Activation of 5-HT1A receptors in the medullary raphé decreases sympathetically mediated brown adipose tissue (BAT) thermogenesis and peripheral vasoconstriction when previously activated with leptin, LPS, prostaglandins, or cooling. It is not known whether shivering is also modulated by medullary raphé 5-HT1A receptors. We previously showed in conscious piglets that activation of 5-HT1A receptors with (±)-8-hydroxy-2-(dipropylamino)-tetralin (8-OH-DPAT) in the paragigantocellularis lateralis (PGCL), a medullary region lateral to the raphé that contains substantial numbers of 5-HT neurons, eliminates rapid eye movement (REM) sleep and decreases shivering in a cold environment, but does not attenuate peripheral vasoconstriction. Hoffman JM, Brown JW, Sirlin EA, Benoit AM, Gill WH, Harris MB, Darnall RA. Am J Physiol Regul Integr Comp Physiol 293: R518–R527, 2007. We hypothesized that, during cooling, activation of 5-HT1A receptors in the medullary raphé would also eliminate REM sleep and, in contrast to activation of 5-HT1A receptors in the PGCL, would attenuate both shivering and peripheral vasoconstriction. In a continuously cool environment, dialysis of 8-OH-DPAT into the medullary raphé resulted in alternating brief periods of non-REM sleep and wakefulness and eliminated REM sleep, as observed when 8-OH-DPAT is dialyzed into the PGCL. Moreover, both shivering and peripheral vasoconstriction were significantly attenuated after 8-OH-DPAT dialysis into the medullary raphé. The effects of 8-OH-DPAT were prevented after dialysis of the selective 5-HT1A receptor antagonist WAY-100635. We conclude that, during cooling, exogenous activation of 5-HT1A receptors in the medullary raphé decreases both shivering and peripheral vasoconstriction. Our data are consistent with the hypothesis that neurons expressing 5-HT1A receptors in the medullary raphé facilitate spinal motor circuits involved in shivering, as well as sympathetic stimulation of other thermoregulatory effector mechanisms.
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