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Chen CW, Chou YH, Liou YJ, Yang KC, Hu LY, Hsieh WC, Liu MN. Amygdala substructure volumes and serotonin transporter in first-episode, drug- naïve major depressive disorder: A pilot study. J Psychiatr Res 2023; 160:210-216. [PMID: 36857985 DOI: 10.1016/j.jpsychires.2023.02.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Revised: 02/07/2023] [Accepted: 02/09/2023] [Indexed: 02/23/2023]
Abstract
INTRODUCTION Amygdala and serotonergic system abnormalities have been documented in major depressive disorder (MDD). However, most studies have been conducted on recurrent MDD, and only a few have assessed their interaction. This study aimed to concurrently examine both the amygdala and serotonergic systems and their clinical relevance in first-episode, drug-naïve MDD. METHODS This study included 27 patients with first-episode, drug-naïve MDD and 27 age- and gender-matched healthy controls (HCs). The amygdala substructure volumes were performed with Freesurfer from a 1.5 T magnetic resonance image. Serotonin transporter (SERT) availability was detected by single-photon emission computed tomography with 123I-ADAM. The Benjamini-Hochberg method was applied to adjust for multiple comparisons. RESULTS No significant difference was found in the amygdala substructure volume and SERT availability between the two groups, respectively. Within MDD patients, the right medial, cortical nucleus, and centromedial volumes were positively associated with caudate SERT availability, respectively. Moreover, the right lateral nucleus volume in the amygdala was positively correlated with depression severity. However, these significances did not survive correction for multiple testing. CONCLUSIONS There were no significant abnormalities in the amygdala substructure volumes and SERT availability in patients with first-episode, drug-naïve MDD. We did not observe an association between amygdala substructure volume and serotonergic dysregulation and their correlations with depression severity in patients with MDD. A larger sample size is warranted to elucidate the actual correlation.
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Affiliation(s)
- Ching-Wen Chen
- Department of Pharmacy, Kaohsiung Veterans General Hospital, Kaohsiung, 813414, Taiwan; Department of Pharmacy and Master Program, College of Pharmacy and Health Care, Tajen University, Pingtung, 90741, Taiwan
| | - Yuan-Hwa Chou
- Center for Quality Management, Taipei Veterans General Hospital, Taipei, 112201, Taiwan; Department of Psychiatry, Taipei Veterans General Hospital, Taipei, 112201, Taiwan; School of Medicine, National Yang Ming Chiao Tung University, Taipei, 112304, Taiwan
| | - Ying-Jay Liou
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, 112201, Taiwan; School of Medicine, National Yang Ming Chiao Tung University, Taipei, 112304, Taiwan
| | - Kai-Chun Yang
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, 112201, Taiwan; School of Medicine, National Yang Ming Chiao Tung University, Taipei, 112304, Taiwan
| | - Li-Yu Hu
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, 112201, Taiwan; School of Medicine, National Yang Ming Chiao Tung University, Taipei, 112304, Taiwan
| | - Wen-Chi Hsieh
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, 112201, Taiwan
| | - Mu-N Liu
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, 112201, Taiwan; School of Medicine, National Yang Ming Chiao Tung University, Taipei, 112304, Taiwan.
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Chiu YC, Yang BH, Yang KC, Liu MN, Hu LY, Liou YJ, Chan LY, Chou YH. A study of tryptophan, kynurenine and serotonin transporter in first-episode drug-naïve major depressive disorder. Psychiatry Res Neuroimaging 2021; 312:111296. [PMID: 33945927 DOI: 10.1016/j.pscychresns.2021.111296] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 04/16/2021] [Accepted: 04/22/2021] [Indexed: 11/24/2022]
Abstract
Major depressive disorder (MDD) is associated with the disharmonic functioning of the serotonin system. The serotonin system is mainly modulated by the serotonin transporter (SERT) which regulates serotonin uptake and the metabolism of its precursor, tryptophan and following kynurenine pathway. Currently, there is a lack of research examining both markers concurrently in MDD. This study evaluated the alterations and inter-relationships of both markers in first-episode drug-naïve MDD patients. Thirty-three MDD patients and 33 age- and sex-matched healthy controls (HC) were recruited. The SERT availability were comparable between two groups in the midbrain, thalamus, caudate, and putamen. The kynurenine/tryptophan ratio which indicates tryptophan metabolism was lower in MDD than HC with no group difference in the tryptophan or kynurenine concentration. A negative correlation between the midbrain SERT availability and kynurenine concentration in HC was found. For the subgroup of HC with high kynurenine/tryptophan ratio, the SERT availability was positively associated with the kynurenine/tryptophan ratio and negatively correlated with tryptophan or kynurenine concentration. This study demonstrated the altered tryptophan metabolism and the relationship between tryptophan metabolism and the SERT availability in first-episode drug-naïve MDD patients, which gave a new insight towards the future investigation of the pathophysiology of MDD.
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Affiliation(s)
- Yen-Chen Chiu
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan; Center for Quality Management, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Bang-Hung Yang
- Department of Nuclear Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Kai-Chin Yang
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Psychiatry, Faculty of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Mu-N Liu
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Psychiatry, Faculty of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Li-Yu Hu
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Psychiatry, Faculty of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Ying-Jay Liou
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Psychiatry, Faculty of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Li-Yi Chan
- Center for Quality Management, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Yuan-Hwa Chou
- Department of Psychiatry, Taipei Veterans General Hospital, Taipei, Taiwan; Center for Quality Management, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Psychiatry, Faculty of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan.
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Hernandes PM, Batistela MF, Vilela-Costa HH, Sant'Ana AB, Kumpel VD, Tirapelle MC, Bom ADOP, de Andrade TGCS, Zangrossi H. Role of 5-HT 1A receptors in the ventral hippocampus in the regulation of anxiety- and panic-related defensive behaviors in rats. Behav Brain Res 2021; 408:113296. [PMID: 33862061 DOI: 10.1016/j.bbr.2021.113296] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 04/06/2021] [Accepted: 04/11/2021] [Indexed: 01/04/2023]
Abstract
Changes in 5-HT1A receptor (5-HT1AR)-mediated neurotransmission in the hippocampus have been associated with anxiety, depression and in the mode of action of antidepressant drugs. It has been commonly accepted that whereas the dorsal pole of the hippocampus (DH) is involved in cognitive processing, the ventral pole (VH) is associated with emotional regulation. However, to date, only a few studies have directly addressed the role played by VH 5-HT1ARs in anxiety and panic processing, and their results are conflicting. Here we report that intra-VH administration of the 5-HT1A receptor agonist 8-OH-DPAT, the endogenous agonist serotonin (5-HT), or the standard anxiolytic benzodiazepine midazolam impaired the acquisition of inhibitory avoidance in the elevated T-maze (ETM) of male Wistar rats, indicating an anxiolytic effect. Conversely, local injection of the 5-HT1AR antagonist WAY-100635 caused the opposite effect. These results were equally found in the Vogel conflict test. None of these drugs interfered with locomotor activity in the open-field test, nor did they alter the expression of the escape response in the ETM, a defensive behavior associated with panic. Pre-injection of a sub-effective dose of WAY-100635 in the VH blocked the anxiolytic effect of 5-HT or 8-OH-DPAT in the Vogel test, confirming the involvement of 5-HT1AR for this behavioral effect. The effect in this test was anxiety-selective as none of the drugs affected water consumption or nociception. In conclusion, our results suggest that 5-HT1ARs in the VH play a tonic inhibitory role in anxiety processing. These receptors, however, are not involved in the regulation of panic-related escape behavior.
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Affiliation(s)
- Paloma Molina Hernandes
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, SP, Brazil
| | - Matheus Fitipaldi Batistela
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, SP, Brazil
| | - Heloísa Helena Vilela-Costa
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, SP, Brazil
| | - Ana Beatriz Sant'Ana
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, SP, Brazil
| | - Vinicíus Dias Kumpel
- Department of Biological Science, São Paulo State University (UNESP), Assis, SP, Brazil
| | | | | | | | - Hélio Zangrossi
- Department of Pharmacology, School of Medicine of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, SP, Brazil.
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Kasture AS, Bartel D, Steinkellner T, Sucic S, Hummel T, Freissmuth M. Distinct contribution of axonal and somatodendritic serotonin transporters in drosophila olfaction. Neuropharmacology 2019; 161:107564. [PMID: 30851308 DOI: 10.1016/j.neuropharm.2019.03.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 02/11/2019] [Accepted: 03/03/2019] [Indexed: 01/07/2023]
Abstract
The serotonin transporter (SERT) regulates serotonergic neurotransmission by retrieving released serotonin and replenishing vesicular stores. SERT is not only delivered to axons but it is also present on the neuronal soma and on dendrites. It has not been possible to restrict the distribution of SERT without affecting transporter function. Hence, the physiological role of somatodendritic SERT remains enigmatic. The SERT C-terminus harbors a conserved RI-motif, which recruits SEC24C, a cargo receptor in the coatomer protein-II coat. Failure to engage SEC24C precludes axonal enrichment of SERT. Here we introduced a point mutation into the RI-motif of human SERT causing confinement of the resulting - otherwise fully functional - hSERT-R607A on the somatodendritic membrane of primary rat dorsal raphe neurons. Transgenic expression of the corresponding Drosophila mutant dSERT-R599A led to its enrichment in the somatodendritic compartment of serotonergic neurons in the fly brain. We explored the possible physiological role of somatodendritic SERT by comparing flies harboring wild type SERT and dSERT-R599A in a behavioral paradigm for serotonin-modulated odor perception. When globally re-expressed in serotonergic neurons, wild type SERT but not dSERT-R599A restored ethanol preference. In contrast, dSERT-R599A restored ethanol preference after targeted expression in contralaterally projecting, serotonin-immunoreactive deuterocerebral (CSD) interneurons, while expression of wild type SERT caused ethanol aversion. We conclude that, in CSD neurons, (i) somatodendritic SERT supports ethanol attraction, (ii) axonal SERT specifies ethanol aversion, (iii) the effect of axonal SERT can override that of somatodendritic SERT. These observations demonstrate a distinct biological role of somatodendritic and axonal serotonin transport. This article is part of the issue entitled 'Special Issue on Neurotransmitter Transporters'.
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Affiliation(s)
- Ameya Sanjay Kasture
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria; Department of Neurobiology, University of Vienna, A-1090 Vienna, Austria
| | - Daniela Bartel
- Department of Neurobiology, University of Vienna, A-1090 Vienna, Austria
| | - Thomas Steinkellner
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Sonja Sucic
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Thomas Hummel
- Department of Neurobiology, University of Vienna, A-1090 Vienna, Austria
| | - Michael Freissmuth
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria.
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5
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James GM, Gryglewski G, Vanicek T, Berroterán-Infante N, Philippe C, Kautzky A, Nics L, Vraka C, Godbersen GM, Unterholzner J, Sigurdardottir HL, Spies M, Seiger R, Kranz GS, Hahn A, Mitterhauser M, Wadsak W, Bauer A, Hacker M, Kasper S, Lanzenberger R. Parcellation of the Human Cerebral Cortex Based on Molecular Targets in the Serotonin System Quantified by Positron Emission Tomography In vivo. Cereb Cortex 2019; 29:372-382. [PMID: 30357321 PMCID: PMC6294402 DOI: 10.1093/cercor/bhy249] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 09/05/2018] [Accepted: 09/06/2018] [Indexed: 01/21/2023] Open
Abstract
Parcellation of distinct areas in the cerebral cortex has a long history in neuroscience and is of great value for the study of brain function, specialization, and alterations in neuropsychiatric disorders. Analysis of cytoarchitectonical features has revealed their close association with molecular profiles based on protein density. This provides a rationale for the use of in vivo molecular imaging data for parcellation of the cortex with the advantage of whole-brain coverage. In the current work, parcellation was based on expression of key players of the serotonin neurotransmitter system. Positron emission tomography was carried out for the quantification of serotonin 1A (5-HT1A, n = 30) and 5-HT2A receptors (n = 22), the serotonin-degrading enzyme monoamine oxidase A (MAO-A, n = 32) and the serotonin transporter (5-HTT, n = 24) in healthy participants. Cortical protein distribution maps were obtained using surface-based quantification. Based on k-means clustering, silhouette criterion and bootstrapping, five distinct clusters were identified as the optimal solution. The defined clusters proved of high explanatory value for the effects of psychotropic drugs acting on the serotonin system, such as antidepressants and psychedelics. Therefore, the proposed method constitutes a sensible approach towards integration of multimodal imaging data for research and development in neuropharmacology and psychiatry.
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Affiliation(s)
- Gregory M James
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Gregor Gryglewski
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Thomas Vanicek
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Neydher Berroterán-Infante
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria
| | - Cécile Philippe
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria
| | - Alexander Kautzky
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Lukas Nics
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria
| | - Chrysoula Vraka
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria
| | - Godber M Godbersen
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Jakob Unterholzner
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Helen L Sigurdardottir
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Marie Spies
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - René Seiger
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Georg S Kranz
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University Hong Kong, China
| | - Andreas Hahn
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Markus Mitterhauser
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria
- Ludwig Boltzmann Institute Applied Diagnostics, Vienna, Austria
| | - Wolfgang Wadsak
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria
- Center for Biomarker Research in Medicine (CBmed), Graz, Austria
| | - Andreas Bauer
- Institute of Neuroscience and Medicine (INM-2), Research Centre Jülich, Jülich, Germany
| | - Marcus Hacker
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Vienna, Austria
| | - Siegfried Kasper
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Rupert Lanzenberger
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
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6
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Komorowski A, James GM, Philippe C, Gryglewski G, Bauer A, Hienert M, Spies M, Kautzky A, Vanicek T, Hahn A, Traub-Weidinger T, Winkler D, Wadsak W, Mitterhauser M, Hacker M, Kasper S, Lanzenberger R. Association of Protein Distribution and Gene Expression Revealed by PET and Post-Mortem Quantification in the Serotonergic System of the Human Brain. Cereb Cortex 2018; 27:117-130. [PMID: 27909009 PMCID: PMC5939202 DOI: 10.1093/cercor/bhw355] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Indexed: 12/12/2022] Open
Abstract
Regional differences in posttranscriptional mechanisms may influence in vivo protein densities. The association of positron emission tomography (PET) imaging data from 112 healthy controls and gene expression values from the Allen Human Brain Atlas, based on post-mortem brains, was investigated for key serotonergic proteins. PET binding values and gene expression intensities were correlated for the main inhibitory (5-HT1A) and excitatory (5-HT2A) serotonin receptor, the serotonin transporter (SERT) as well as monoamine oxidase-A (MAO-A), using Spearman's correlation coefficients (rs) in a voxel-wise and region-wise analysis. Correlations indicated a strong linear relationship between gene and protein expression for both the 5-HT1A (voxel-wise rs = 0.71; region-wise rs = 0.93) and the 5-HT2A receptor (rs = 0.66; 0.75), but only a weak association for MAO-A (rs = 0.26; 0.66) and no clear correlation for SERT (rs = 0.17; 0.29). Additionally, region-wise correlations were performed using mRNA expression from the HBT, yielding comparable results (5-HT1Ars = 0.82; 5-HT2Ars = 0.88; MAO-A rs = 0.50; SERT rs = -0.01). The SERT and MAO-A appear to be regulated in a region-specific manner across the whole brain. In contrast, the serotonin-1A and -2A receptors are presumably targeted by common posttranscriptional processes similar in all brain areas suggesting the applicability of mRNA expression as surrogate parameter for density of these proteins.
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Affiliation(s)
- A Komorowski
- Department of Psychiatry and Pychotherapy, Division of Biological Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - G M James
- Department of Psychiatry and Pychotherapy, Division of Biological Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - C Philippe
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - G Gryglewski
- Department of Psychiatry and Pychotherapy, Division of Biological Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - A Bauer
- Institute of Neuroscience and Medicine (INM-2), Research Centre Jülich, 52425 Jülich, Germany
| | - M Hienert
- Department of Psychiatry and Pychotherapy, Division of Biological Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - M Spies
- Department of Psychiatry and Pychotherapy, Division of Biological Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - A Kautzky
- Department of Psychiatry and Pychotherapy, Division of Biological Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - T Vanicek
- Department of Psychiatry and Pychotherapy, Division of Biological Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - A Hahn
- Department of Psychiatry and Pychotherapy, Division of Biological Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - T Traub-Weidinger
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - D Winkler
- Department of Psychiatry and Pychotherapy, Division of Biological Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - W Wadsak
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - M Mitterhauser
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - M Hacker
- Department of Biomedical Imaging and Image-guided Therapy, Division of Nuclear Medicine, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - S Kasper
- Department of Psychiatry and Pychotherapy, Division of Biological Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - R Lanzenberger
- Department of Psychiatry and Pychotherapy, Division of Biological Psychiatry, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
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Mlinar B, Corradetti R. Differential modulation of CA1 impulse flow by endogenous serotonin along the hippocampal longitudinal axis. Hippocampus 2018; 28:217-225. [DOI: 10.1002/hipo.22825] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Revised: 12/11/2017] [Accepted: 12/14/2017] [Indexed: 11/08/2022]
Affiliation(s)
- Boris Mlinar
- Department of Neuroscience, Psychology, Drug Research and Child Health; University of Florence; Florence Italy
| | - Renato Corradetti
- Department of Neuroscience, Psychology, Drug Research and Child Health; University of Florence; Florence Italy
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De Deurwaerdère P, Di Giovanni G. Serotonergic modulation of the activity of mesencephalic dopaminergic systems: Therapeutic implications. Prog Neurobiol 2016; 151:175-236. [PMID: 27013075 DOI: 10.1016/j.pneurobio.2016.03.004] [Citation(s) in RCA: 114] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Revised: 03/13/2016] [Accepted: 03/14/2016] [Indexed: 12/14/2022]
Abstract
Since their discovery in the mammalian brain, it has been apparent that serotonin (5-HT) and dopamine (DA) interactions play a key role in normal and abnormal behavior. Therefore, disclosure of this interaction could reveal important insights into the pathogenesis of various neuropsychiatric diseases including schizophrenia, depression and drug addiction or neurological conditions such as Parkinson's disease and Tourette's syndrome. Unfortunately, this interaction remains difficult to study for many reasons, including the rich and widespread innervations of 5-HT and DA in the brain, the plethora of 5-HT receptors and the release of co-transmitters by 5-HT and DA neurons. The purpose of this review is to present electrophysiological and biochemical data showing that endogenous 5-HT and pharmacological 5-HT ligands modify the mesencephalic DA systems' activity. 5-HT receptors may control DA neuron activity in a state-dependent and region-dependent manner. 5-HT controls the activity of DA neurons in a phasic and excitatory manner, except for the control exerted by 5-HT2C receptors which appears to also be tonically and/or constitutively inhibitory. The functional interaction between the two monoamines will also be discussed in view of the mechanism of action of antidepressants, antipsychotics, anti-Parkinsonians and drugs of abuse.
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Affiliation(s)
- Philippe De Deurwaerdère
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5293, 33076 Bordeaux Cedex, France.
| | - Giuseppe Di Giovanni
- Department of Physiology & Biochemistry, Faculty of Medicine and Surgery, University of Malta, Malta; Neuroscience Division, School of Biosciences, Cardiff University, Cardiff, UK.
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Krishnadas R, Nicol A, Sassarini J, Puri N, Burden AD, Leman J, Combet E, Pimlott S, Hadley D, McInnes IB, Cavanagh J. Circulating tumour necrosis factor is highly correlated with brainstem serotonin transporter availability in humans. Brain Behav Immun 2016; 51:29-38. [PMID: 26255693 DOI: 10.1016/j.bbi.2015.08.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 08/04/2015] [Accepted: 08/04/2015] [Indexed: 11/24/2022] Open
Abstract
Preclinical studies demonstrate that pro-inflammatory cytokines increase serotonin transporter availability and function, leading to depressive symptoms in rodent models. Herein we investigate associations between circulating inflammatory markers and brainstem serotonin transporter (5-HTT) availability in humans. We hypothesised that higher circulating inflammatory cytokine concentrations, particularly of tumour necrosis factor (TNF-α), would be associated with greater 5-HTT availability, and that TNF-α inhibition with etanercept (sTNFR:Fc) would in turn reduce 5-HTT availability. In 13 neurologically healthy adult women, plasma TNF-α correlated significantly with 5-HTT availability (rho=0.6; p=0.03) determined by [(123)I]-beta-CIT SPECT scanning. This association was replicated in an independent sample of 12 patients with psoriasis/psoriatic arthritis (rho=0.76; p=0.003). Indirect effects analysis, showed that there was a significant overlap in the variance explained by 5-HTT availability and TNF-α concentrations on BDI scores. Treatment with etanercept for 6-8weeks was associated with a significant reduction in 5-HTT availability (Z=2.09; p=0.03; r=0.6) consistent with a functional link. Our findings confirm an association between TNF-α and 5-HTT in both the basal physiological and pathological condition. Modulation of both TNF-α and 5-HTT by etanercept indicate the presence of a mechanistic pathway whereby circulating inflammatory cytokines are related to central nervous system substrates underlying major depression.
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Affiliation(s)
- Rajeev Krishnadas
- Sackler Institute of Psychobiological Research, Institute of Health and Wellbeing, University of Glasgow, United Kingdom.
| | - Alice Nicol
- Institute of Neurological Sciences, Southern General Hospital, Glasgow, United Kingdom
| | - Jen Sassarini
- School of Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom
| | - Navesh Puri
- Sackler Institute of Psychobiological Research, Institute of Health and Wellbeing, University of Glasgow, United Kingdom
| | - A David Burden
- Department of Dermatology, Western Infirmary, Glasgow, United Kingdom
| | - Joyce Leman
- Department of Dermatology, Western Infirmary, Glasgow, United Kingdom
| | - Emilie Combet
- School of Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom
| | - Sally Pimlott
- West of Scotland Radionuclide Dispensary, Greater Glasgow and Clyde NHS Trust, United Kingdom
| | - Donald Hadley
- Institute of Neurological Sciences, Southern General Hospital, Glasgow, United Kingdom
| | - Iain B McInnes
- Institute of Infection, Immunity and Inflammation, University of Glasgow, United Kingdom
| | - Jonathan Cavanagh
- Sackler Institute of Psychobiological Research, Institute of Health and Wellbeing, University of Glasgow, United Kingdom.
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10
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Gryglewski G, Lanzenberger R, Kranz GS, Cumming P. Meta-analysis of molecular imaging of serotonin transporters in major depression. J Cereb Blood Flow Metab 2014; 34:1096-103. [PMID: 24802331 PMCID: PMC4083395 DOI: 10.1038/jcbfm.2014.82] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 04/04/2014] [Accepted: 04/09/2014] [Indexed: 11/16/2022]
Abstract
The success of serotonin-selective reuptake inhibitors has lent support to the monoamine theory of major depressive disorder (MDD). This issue has been addressed in a number of molecular imaging studies by positron emission tomography or single-photon emission computed tomography of serotonin reuptake sites (5-HTT) in the brain of patients with MDD, with strikingly disparate conclusions. Our meta-analysis of the 18 such studies, totaling 364 MDD patients free from significant comorbidities or medication and 372 control subjects, revealed reductions in midbrain 5-HTT (Hedges' g=-0.49; 95% CI: (-0.84, -0.14)) and amygdala (Hedges' g=-0.50; 95% CI: (-0.78, -0.22)), which no individual study possessed sufficient power to detect. Only small effect sizes were found in other regions with high binding (thalamus: g=-0.24, striatum: g=-0.32, and brainstem g=-0.22), and no difference in the frontal or cingulate cortex. Age emerged as an important moderator of 5-HTT availability in MDD, with more severe reductions in striatal 5-HTT evident with greater age of the study populations (P<0.01). There was a strong relationship between severity of depression and 5-HTT reductions in the amygdala (P=0.01). Thus, molecular imaging findings indeed reveal widespread reductions of ∼10% in 5-HTT availability in MDD, which may predict altered spatial-temporal dynamics of serotonergic neurotransmission.
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Affiliation(s)
- Gregor Gryglewski
- Functional, Molecular & Translational Neuroimaging Lab, Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Rupert Lanzenberger
- Functional, Molecular & Translational Neuroimaging Lab, Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Georg S Kranz
- Functional, Molecular & Translational Neuroimaging Lab, Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Paul Cumming
- Department of Nuclear Medicine, Friederich-Alexanders Universitaet, Erlangen/Nurenberg, Germany
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11
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Brain monoamines and antidepressant-like responses in MRL/MpJ versus C57BL/6J mice. Neuropharmacology 2012; 67:503-10. [PMID: 23220293 DOI: 10.1016/j.neuropharm.2012.11.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 11/26/2012] [Accepted: 11/28/2012] [Indexed: 11/22/2022]
Abstract
The MRL/MpJ mouse demonstrates enhanced wound healing and tissue regeneration and increased neurotrophic mobilization to chronic antidepressant drug treatments. This study compared brain monoamine systems between MRL/MpJ and C57BL/6J mice as a potential basis for strain differences after chronic antidepressant treatment. MRL/MpJ mice had significantly higher tissue levels of serotonin and dopamine in multiple brain regions. Microdialysis studies demonstrated that baseline levels of extracellular serotonin did not differ between strains. However, acute administration of the selective serotonin reuptake inhibitor citalopram produced an increase in extracellular serotonin in the ventral hippocampus of MRL/MpJ mice that was twice as large as achieved in C57BL/6J mice. The greater effects in MRL/MpJ mice on 5-HT levels were not maintained after local perfusion of citalopram, suggesting that mechanisms outside of the hippocampus were responsible for the greater effect of citalopram after systemic injection. The density of serotonin and norepinephrine transporters in the hippocampus was significantly higher in MRL/MpJ mice. In addition, the expression of 5-HT(1A) mRNA was lower in the hippocampus, 5-HT(1B) mRNA was higher in the hippocampus and brainstem and SERT mRNA was higher in the brain stem of MRL/MpJ mice. The exaggerated neurotransmitter release in MRL/MpJ mice was accompanied by reduced baseline immobility in the tail suspension test and a greater reduction of immobility produced by citalopram or the tricyclic antidepressant desipramine. These data suggest that differences in the response to acute and chronic antidepressant treatments between the two strains could be attributed to differences in serotonin or catecholamine transmission.
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12
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Navailles S, De Deurwaerdère P. Presynaptic control of serotonin on striatal dopamine function. Psychopharmacology (Berl) 2011; 213:213-42. [PMID: 20953589 DOI: 10.1007/s00213-010-2029-y] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Accepted: 09/14/2010] [Indexed: 11/27/2022]
Abstract
RATIONALE The influences of the serotonergic system on dopamine (DA) neuron activity have received considerable attention during the last three decades due to the real opportunity to improve disorders related to central DA neuron dysfunctions such as Parkinson's disease, schizophrenia, or drug abuse with serotonergic drugs. Numerous biochemical and behavioral data indicate that serotonin (5-HT) affects dopaminergic terminal function in the striatum. OBJECTIVE The authors propose a thorough examination of data showing controversial effects induced by striatal 5-HT on dopaminergic activity. RESULTS Inhibitory and excitatory effects of exogenous 5-HT have been reported on DA release and synthesis, involving various striatal 5-HT receptors. 5-HT also promotes an efflux of DA through reversal of the direction of DA transport. By analogy with the mechanism of action described for amphetamine, the consequences of 5-HT entering DA terminals might explain both the excitatory and inhibitory effects of 5-HT on presynaptic DA terminal activity, but the physiological relevance of this mechanism is far from clear. The recent data suggest that the endogenous 5-HT system affects striatal DA release in a state-dependent manner associated with the conditional involvement of various 5-HT receptors such as 5-HT(2A), 5-HT(2C), 5-HT(3), and 5-HT(4) receptors. CONCLUSION Methodological and pharmacological issues have prevented a comprehensive overview of the influence of 5-HT on striatal DA activity. The distribution of striatal 5-HT receptors and their restricted influence on DA neuron activity suggest that the endogenous 5-HT system exerts multiple and subtle influences on DA-mediated behaviors.
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Affiliation(s)
- Sylvia Navailles
- Unité Mixte de Recherche Centre National de la Recherche Scientifique 5227, Université Victor Segalen Bordeaux 2, Bordeaux, France
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13
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Agnati LF, Guidolin D, Fuxe K. The brain as a system of nested but partially overlapping networks. Heuristic relevance of the model for brain physiology and pathology. J Neural Transm (Vienna) 2006; 114:3-19. [PMID: 16906353 DOI: 10.1007/s00702-006-0563-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2005] [Accepted: 07/14/2006] [Indexed: 10/24/2022]
Abstract
A new model of the brain organization is proposed. The model is based on the assumption that a global molecular network enmeshes the entire central nervous system. Thus, brain extra-cellular and intra-cellular molecular networks are proposed to communicate at the level of special plasma membrane regions (e.g., the lipid rafts) where horizontal molecular networks can represent input/output regions allowing the cell to have informational exchanges with the extracellular environment. Furthermore, some "pervasive signals" such as field potentials, pressure waves and thermal gradients that affect large parts of the brain cellular and molecular networks are discussed. Finally, at least two learning paradigms are analyzed taking into account the possible role of Volume Transmission: the so-called model of "temporal difference learning" and the "Turing B-unorganised machine". The relevance of this new view of brain organization for a deeper understanding of some neurophysiological and neuropathological aspects of its function is briefly discussed.
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Affiliation(s)
- L F Agnati
- Department of Biomedical Sciences, University of Modena and Reggio Emilia and IRCCS, Ospedale San Camillo, Venezia, Italy.
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14
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Zeng Z, Chen TB, Miller PJ, Dean D, Tang YS, Sur C, Williams DL. The serotonin transporter in rhesus monkey brain: comparison of DASB and citalopram binding sites. Nucl Med Biol 2006; 33:555-63. [PMID: 16720249 DOI: 10.1016/j.nucmedbio.2006.02.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Revised: 02/13/2006] [Accepted: 02/26/2006] [Indexed: 11/19/2022]
Abstract
We have characterized the interaction of the serotonin transporter ligand [3H]-N,N-dimethyl-2-(2-amino-4-cyanophenylthio)-benzylamine (DASB) with rhesus monkey brain in vitro using tissue homogenate binding and autoradiographic mapping. [3H]-DASB, a tritiated version of the widely used [11C] positron emission tomography tracer, was found to selectively bind to a single population of sites with high affinity (K(d)=0.20+/-0.04 nM). The serotonin transporter density (B(max)) obtained for rhesus frontal cortex was found to be 66+/-8 fmol/mg protein using [3H]-DASB, similar to the B(max) value obtained using the reference radioligand [3H]-citalopram, a well-characterized and highly selective serotonin reuptake inhibitor (83+/-22 fmol/mg protein). Specific binding sites of both [3H]-DASB and [3H]-citalopram were similarly and nonuniformly distributed throughout the rhesus central nervous system, in a pattern consistent with serotonin transporter localization reported for human brain. Regional serotonin transporter densities, estimated from optical densities of the autoradiographic images, were well correlated between the two radioligands. Finally, DASB and fluoxetine showed dose-dependent full inhibition of [3H]-citalopram binding in a competition autoradiographic study, with K(i) values in close agreement with those obtained from rhesus brain homogenates. This side-by-side comparison of [3H]-DASB and [3H]-citalopram binding sites in rhesus tissue homogenates and in adjacent rhesus brain slices provides additional support for the use of [11C]-DASB to assess the availability and distribution of serotonin transporters in nonhuman primates.
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Affiliation(s)
- Zhizhen Zeng
- Imaging Department, Merck Research Laboratories, West Point, PA 19486, USA.
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15
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HUMBLOT N, THIRIET N, GOBAILLE S, AUNIS D, ZWILLER J. The Serotonergic System Modulates the Cocaine-Induced Expression of the Immediate Early Genesegr-1andc-fosin Rat Brain. Ann N Y Acad Sci 2006; 844:7-20. [DOI: 10.1111/j.1749-6632.1998.tb08217.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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Bjarkam CR, Sørensen JC, Geneser FA. Distribution and morphology of serotonin-immunoreactive axons in the retrohippocampal areas of the New Zealand white rabbit. ACTA ACUST UNITED AC 2005; 210:199-207. [PMID: 16170538 DOI: 10.1007/s00429-005-0004-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/08/2005] [Indexed: 12/19/2022]
Abstract
This study provides a detailed light microscopic description of the morphology and distribution of serotonin-immunoreactive axons in the paleocortical retrohippocampal areas, viz. the subiculum, presubiculum, parasubiculum and entorhinal area, and the adjoining neocortical perirhinal and retrosplenial cortices of the New Zealand white rabbit. Serotonergic axons could be segregated into three different fiber types named fine fibers, beaded fibers and stem-axons. Fine fibers were evenly distributed thin axons with small fusiform/granular varicosities. Beaded fibers were thin axons with large varicosities, predominantly located in the retrohippocampal supragranular layers, where they often formed pericellular arrays. Stem-axons were thick straight, nonvaricose axons seen in the white matter of psalterium dorsale, alveus and the plexiform layer. The paleocortical retrohippocampal areas had a dense supragranular innervation with numerous tortuous fine and beaded fibers, intermingled in conglomerates with conspicuous varicosities forming pericellular arrays. In contrast, the neocortical area 17 and the lateral part of the perirhinal cortex (area 36) were innervated by evenly distributed fine fibers with a moderate number of small varicosities and few ramifications, whereas, the retrosplenial cortex (areas 29e, 29ab and 29cd), and the medial part of the perirhinal cortex (area 35) displayed an intermediate innervation pattern, probably reflecting the transitional nature of these areas being located between the paleo- and the neocortex. The described dualistic innervation pattern may functionally enable the serotonergic system to exert a strong influence on the supragranular layers of the retrohippocampal areas and thus on the neural input entering these areas from the perirhinal and neighboring polymodal association neocortices, whereas the innervation pattern in the adjoining neocortical areas points towards a more diffuse and general modulation of neural activity herein.
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Affiliation(s)
- Carsten R Bjarkam
- Department of Neurobiology, Institute of Anatomy, University of Aarhus, 8000 Aarhus C, Denmark.
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17
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O'Shea E, Escobedo I, Orio L, Sanchez V, Navarro M, Green AR, Colado MI. Elevation of ambient room temperature has differential effects on MDMA-induced 5-HT and dopamine release in striatum and nucleus accumbens of rats. Neuropsychopharmacology 2005; 30:1312-23. [PMID: 15688085 DOI: 10.1038/sj.npp.1300673] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
3,4-Methylenedioxymethamphetamine (MDMA) produces acute dopamine and 5-HT release in rat brain and a hyperthermic response, which is dependent on the ambient room temperature in which the animal is housed. We examined the effect of ambient room temperature (20 and 30 degrees C) on MDMA-induced dopamine and 5-HT efflux in the striatum and shell of nucleus accumbens (NAc) of freely moving rats by using microdialysis. Locomotor activity and rectal temperature were also evaluated. In the NAc, MDMA (2.5 or 5 mg/kg, i.p.) produced a substantial increase in extracellular dopamine, which was more marked at 30 degrees C. 5-HT release was also increased by MDMA given at 30 degrees C. In contrast, MDMA-induced extracellular dopamine and 5-HT increases in the striatum were unaffected by ambient temperature. At 20 degrees C room temperature, MDMA did not modify the rectal temperature but at 30 degrees C it produced a rapid and sustained hyperthermia. MDMA at 20 degrees C room temperature produced a two-fold increase in activity compared with saline-treated controls. The MDMA-induced increase in locomotor activity was more marked at 30 degrees C due to a decrease in the activity of the saline-treated controls at this high ambient temperature. These results show that high ambient temperature enhances MDMA-induced locomotor activity and monoamine release in the shell of NAc, a region involved in the incentive motivational properties of drugs of abuse, and suggest that the rewarding effects of MDMA may be more pronounced at high ambient temperature.
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Affiliation(s)
- Esther O'Shea
- Departamento de Farmacologia, Facultad de Medicina, Universidad Complutense, Madrid, Spain
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18
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Adams DH, Hanson GR, Keefe KA. 3,4-Methylenedioxymethamphetamine increases neuropeptide messenger RNA expression in rat striatum. ACTA ACUST UNITED AC 2005; 133:131-42. [PMID: 15661373 DOI: 10.1016/j.molbrainres.2004.10.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2004] [Indexed: 11/25/2022]
Abstract
The amphetamine analog 3,4-methylenedioxymethamphetamine (MDMA) is also known as the recreational drug of abuse, Ecstasy. Several neuropeptides are found in striatal neurons postsynaptic to dopamine and serotonin nerve terminals, and changes in neuropeptide neurotransmission may be important for behavioral effects of 3,4-methylenedioxymethamphetamine. This study used in situ hybridization to characterize the effects of 3,4-methylenedioxymethamphetamine on four neuropeptide mRNAs: preprodynorphin, preprotachykinin, neurotensin/neuromedin N, and preproenkephalin. Male, Sprague-Dawley rats received a single administration of 10 mg/kg 3,4-methylenedioxymethamphetamine and were sacrificed 30 min or 3 h later. Three hours after administration, 3,4-methylenedioxymethamphetamine increased preprodynorphin, preprotachykinin, and neurotensin/neuromedin N mRNAs. These increases were most prominent in ventral and medial aspects of the rostral-middle striatum, and then became more dorsally restricted in the caudal striatum. At the 30-minute time point, MDMA significantly decreased the signal for preproenkephalin mRNA in a general manner but did not affect the signal for the other neuropeptide precursors. These data suggest that 3,4-methylenedioxymethamphetamine has a generalized, transient, inhibitory effect on striatopallidal neuron gene expression, and then preferentially influences striatonigral neuropeptide systems at the later time point in a regionally selective manner.
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Affiliation(s)
- David H Adams
- Department of Pharmacology and Toxicology, University of Utah, 30 South 2000 East, Rm. 201, Salt Lake City, UT 84112-5820, USA
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19
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Owashi T, Iritani S, Niizato K, Ikeda K, Kamijima K. The distribution of serotonin transporter immunoreactivity in hippocampal formation in monkeys and rats. Brain Res 2004; 1010:166-8. [PMID: 15126130 DOI: 10.1016/j.brainres.2004.03.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/01/2004] [Indexed: 01/06/2023]
Abstract
To elucidate the anatomical distribution of the serotonergic neurotransmitter system, we identified serotonin transporter (5-HTT) in the hippocampus of rats and monkeys by immunohistochemistry. A widespread and heterogeneous distribution of 5-HTT-immunoreactive fine fibers was noted in the rat brain. However, in monkeys, punctuate 5-HTT-immunoreactive deposits and fewer fibers were observed. The species difference in 5-HTT immunohistochemical staining pattern may be caused by differences in localization of 5-HTT between species.
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Affiliation(s)
- Toshimi Owashi
- Department of Psychiatry, Showa University School of Medicine, 1-5-8, Hatanodai, Shinagawa, Tokyo 142-8666, Japan.
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20
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Bjarkam CR, Sørensen JC, Geneser FA. Distribution and morphology of serotonin-immunoreactive axons in the hippocampal region of the New Zealand white rabbit. I. Area dentata and hippocampus. Hippocampus 2003; 13:21-37. [PMID: 12625454 DOI: 10.1002/hipo.10042] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This study provides a detailed light microscopic description of the morphology and distribution of immunohistochemically stained serotonergic axons in the hippocampal region of the New Zealand white rabbit. The serotonergic axons were segregated morphologically into three types: beaded fibers, fine fibers, and stem-axons, respectively. Beaded fibers were thin serotonergic axons with large varicosities, whereas thin axons with small fusiform or granular varicosities were called fine fibers. Finally, thick straight non-varicose axons were called stem-axons. Beaded fibers often formed large conglomerates with numerous boutons (pericellular arrays) in close apposition to the cell-rich layers in the hippocampal region, e.g., the granular and hilar cell layers of the dentate area and the pyramidal cell layer ventrally in CA3. The pericellular arrays in these layers were often encountered in relation to small calbindin-D2BK-positive cells, as shown by immunohistochemical double staining for serotonin and calbindin-D28K. The beaded and fine serotonergic fibers displayed a specific innervation pattern in the hippocampal region and were encountered predominantly within the terminal field of the perforant path, e.g., the stratum moleculare hippocampi and the outer two-thirds of the dentate molecular layer. These fibers were also frequently seen in the deep part of the stratum oriens and the alveus, forming a dense plexus in relation to large multipolar calbindin-D28K-positive cells and their basal extensions. Stem-axons were primarily seen in the fimbria and alveus. This innervation pattern was present throughout the entire hippocampal formation, but there were considerable septotemporal differences in the density of the serotonergic innervation. A high density of innervation prevailed in the ventral/temporal part of the hippocampal formation, whereas the dorsal/septal part received only a moderate to weak serotonergic innervation. These results suggest that the serotonergic system could modulate the internal hippocampal circuitry by way of its innervation in the terminal field of the perforant path, the hilus fasciae dentatae, and ventrally in the zone closely apposed to the mossy fiber layer and the pyramidal cells of CA3. This modulation could be of a dual nature, mediated directly by single serotonergic fibers traversing the hippocampal layers or indirectly by the pericellular arrays and their close relation to the calbindin-D28K-positive cells. The marked septotemporal differences in innervation density point toward a difference between the ventral and dorsal parts of the hippocampal formation with respect to serotonergic function and need for serotonergic modulation.
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Affiliation(s)
- Carsten R Bjarkam
- Department of Neurobiology, Institute of Anatomy, University of Aarhus, Denmark.
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21
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Pradhan AAA, Cumming P, Clarke PBS. [125I]Epibatidine-labelled nicotinic receptors in the extended striatum and cerebral cortex: lack of association with serotonergic afferents. Brain Res 2002; 954:227-36. [PMID: 12414106 DOI: 10.1016/s0006-8993(02)03340-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In rat extended striatum, most nicotinic cholinoceptors are likely to be presynaptic. A previous report suggested that DA and 5-HT afferents each account for at least 30% of nicotinic binding sites in the striatum. To explore this question further, rats received unilateral infusions of the neurotoxins 5,7-dihydroxytryptamine, 6-hydroxydopamine or vehicle into the medial forebrain bundle, and were sacrificed 3 weeks later. Denervation was quantified by [125I]RTI-55 autoradiography, using separate assay conditions that revealed DA and 5-HT transporters (i.e. DAT and SERT). Nicotinic cholinoceptors were quantified by [125I]epibatidine autoradiography. Infusion of 6-hydroxydopamine depleted DAT but not SERT labelling in all striatal areas (i.e. caudate-putamen, nucleus accumbens core and shell, olfactory tubercle). The serotonergic neurotoxin 5,7-dihydroxytryptamine depleted SERT and, to a lesser extent, DAT labelling. Both neurotoxins reduced [125I]epibatidine binding in striatal areas. Multiple linear regression analysis showed that these reductions in [125I]epibatidine binding were entirely associated with loss of DAT rather than SERT. The DAT-associated proportion of total [125I]epibatidine binding was 36+/-2% (caudate-putamen), 28+/-3% (accumbens core), 27+/-4% (accumbens shell) and 44+/-5% (olfactory tubercle). Cortical [125I]epibatidine binding was unaltered by 5,7-dihydroxytryptamine lesions that reduced SERT labelling by 46 to 73%. In all brain areas, even small (3.4 to 8.8%) SERT-associated reductions in [125I]epibatidine binding would have been detected as statistically significant. In conclusion, we report the failure to detect nAChRs on 5-HT terminals in extended striatum or cerebral cortex, using a sensitive [125I]epibatidine autoradiographic assay.
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Affiliation(s)
- Amynah A A Pradhan
- Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir William Osler, Montreal, Quebec, Canada H3G 1Y6
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22
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Abstract
The abused drug 3,4-methylenedioxymethamphetamine (MDMA) damages fine serotonergic fibers and nerve terminals in adult organisms; however, developing animals seem less susceptible to this effect. One proposed hypothesis is that neonates are less sensitive to MDMA neurotoxicity because they fail to show drug-induced hyperthermia. We tested this hypothesis by producing hyperthermia in neonatal rats for 2 hours after each of twice-daily MDMA (10 mg/kg sc) or saline injections given over the period from postnatal day (PD) 1 to 4. Other drug-treated and control litters were maintained at normothermic temperatures after injection. Differential core body temperatures were achieved by placing pups (without the dam) in humidified, thermostatically controlled incubators. Temperatures were monitored with a thermocouple probe at 30-minute intervals. Pups subsequently remained undisturbed until sacrifice at PD 25 and PD 60 for assessment of serotonergic damage by measuring 5-HT transporter (SERT) binding in the hippocampus and neocortex as well as 5-HT and 5-HIAA concentrations (PD 25 only). Neonatal MDMA exposure led to significant reductions in both SERT binding and 5-HT levels in the hippocampus at PD 25, independent of body temperature during treatment. Hippocampal SERT binding increased between PD 25 and PD 60 in both the MDMA and saline groups, but the MDMA-related deficit remained unchanged. Interestingly, the neocortex showed no effect of MDMA at PD 25, but SERT binding was significantly reduced at PD 60. Thus, MDMA can exert serotonergic neurotoxicity in developing animals in the absence of elevated body temperature. Hippocampal serotonergic innervation is damaged early, whereas neocortical effects emerge at a later time. Furthermore, the tendency for serotonergic recovery may be less after neonatal MDMA exposure than exposure of adult animals.
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Affiliation(s)
- Jerrold S Meyer
- Department of Psychology, Neuroscience and Behavior Program, University of Massachusetts, Amherst, Massachusetts 01003, USA.
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Zimmer L, Luxen A, Giacomelli F, Pujol JF. Short- and long-term effects of p-ethynylphenylalanine on brain serotonin levels. Neurochem Res 2002; 27:269-75. [PMID: 11958527 DOI: 10.1023/a:1014998926763] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Changes in tissue and extracellular serotonin (5-HT) in raphe dorsalis, raphe medialis and in their main projections areas (hippocampus, striatum and frontal cortex) were investigated at short and long-term times after single injection (5 mg/kg ip) of a novel tryptophan hydroxylase inhibitor, p-ethynylphenylalanine (p-EPA). The 5-HT tissue concentration decreased significantly in raphe nuclei, 30 min post-injection and for 4 days, whereas it decreased from 24 hours post-injection in the 5-HT projections. Normal 5-HT levels reappeared after 12 days post-injection in all areas. Moreover, in the projection areas, the extracellular 5-HT levels decreased rapidly, 90, 40 and 30 min after p-EPA injection, in hippocampus, striatum and frontal cortex, respectively. Decreased accumulation of 5-hydroxytryptophan (5-HTP) under NSD-101 perfusion in the serotoninergic projections after p-EPA injection, confirmed the direct inhibitory effect of the drug on the tryptophan hydroxylase activity. These results demonstrated that p-EPA is a useful pharmacological tool which powerfully, acutely and irreversibly reduces the 5-HT levels.
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Affiliation(s)
- Luc Zimmer
- CERMEP Biomedical Cyclotron, Lyon, France.
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24
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Xu Z, Seidler FJ, Ali SF, Slikker W, Slotkin TA. Fetal and adolescent nicotine administration: effects on CNS serotonergic systems. Brain Res 2001; 914:166-78. [PMID: 11578609 DOI: 10.1016/s0006-8993(01)02797-4] [Citation(s) in RCA: 154] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Nicotine is a neuroteratogen that targets synaptic function during critical developmental stages and recent studies indicate that CNS vulnerability extends into adolescence, the time that smoking typically commences. We administered nicotine to pregnant or adolescent rats via continuous minipump infusions, using dose rates that replicate the plasma nicotine levels found in smokers. Fetal nicotine exposure (gestational days 4-21) decreased the cerebrocortical binding of paroxetine (PXT), a marker for the serotonin (5HT) transporter, likely indicative of a decrease in nerve terminals in that region; the effect lasted into adulthood. There was a corresponding increase in PXT binding in the midbrain/brainstem, the region containing the 5HT cell bodies that project to the cerebral cortex, a pattern typical of reactive sprouting in response to nerve terminal damage. After adolescent nicotine treatment (postnatal days 30-47), PXT binding was reduced in the hippocampus and striatum instead of the cerebral cortex, again accompanied by increased binding in the midbrain and brainstem; the patterns of effects within each region were gender-selective, although both males and females displayed abnormalities. Superimposed on this overall effect, there were transient increases in PXT binding, likely due to acute stimulant effects of nicotine. We also assessed 5HT presynaptic activity (5HIAA/5HT ratio). Withdrawal from adolescent nicotine treatment led to suppression of activity in the cerebral cortex and activation in the midbrain. These results indicate that both fetal and adolescent nicotine exposure elicit apparent damage to 5HT projections with reactive increases in regions containing 5HT cell bodies. Long-term changes in 5HT innervation and/or synaptic activity may play a role in the subsequent development of depression in the offspring of women who smoke during pregnancy or in adolescent smokers.
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Affiliation(s)
- Z Xu
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
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Raines KW, Seidler FJ, Slotkin TA. Alterations in serotonin transporter expression in brain regions of rats exposed neonatally to chlorpyrifos. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2001; 130:65-72. [PMID: 11557094 DOI: 10.1016/s0165-3806(01)00211-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Chlorpyrifos (CPF), one of the most widely-used organophosphate pesticides, is a suspected neuroteratogen. We administered CPF to neonatal rats on postnatal days (PN) 1-4 (1 mg/kg) or PN11-14 (5 mg/kg), treatments devoid of overt toxicity. At the end of the treatment period (PN5 and 15, respectively) and 5-7 days later, we then examined the effects on paroxetine (PXT) binding to the presynaptic 5HT high-affinity transporter, a marker for serotonin (5HT) projections. In males, we found a persistent decrease in PXT binding across the two different treatment regimens, with deficits apparent in a brain region containing 5HT terminal fields (forebrain) as well as in a region containing 5HT cell bodies (brainstem). In contrast, females given the early treatment regimen (PN1-4) showed deficits in the brainstem but transient elevations in the forebrain; the later treatment regimen (PN11-14) had no significant effect on PXT binding in females. These data are consistent with earlier work showing brainstem cell injury resulting from neonatal CPF exposure, and indicate specific damage to 5HT neurons, with a consequent loss of transporter expression in both terminal fields and perikarya. In females, the damage may be temporarily offset by initial trophic effects in the terminal region, consequent to the cholinergic stimulation evoked by cholinesterase inhibition via the active metabolite, CPF oxon. The gender-selective effects on 5HT systems are likely to contribute to similar gender dimorphism in behavioral performance. Because the CPF effects involve 5HT, a neurotransmitter intimately involved in the control of mood, we suggest the need to evaluate behaviors that typify animal models of depression.
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Affiliation(s)
- K W Raines
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, P.O. Box 3813 DUMC, Durham, NC 27710, USA
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26
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Abstract
The regional density of serotonin uptake sites in porcine brain was determined by quantitative radioluminography. Brain cryostat sections 30 microm thick were cut in the sagittal plane and were incubated with [3H]citalopram for selective labeling of serotonin uptake sites. The autoradiograms were quantified using tritium-sensitive radioluminography. The apparent affinity (K(D)) of [3H]citalopram for its binding sites in various brain regions ranged from 2.3-5.6 nM. The density of serotonin uptake sites was highest (200-300 fmol/mg tissue) in the amygdala, superior colliculus, and substantia nigra. Intermediate binding (100 fmol/mg tissue) was present in the dorsomedial thalamus, basal ganglia, and entorhinal cortex. Traces of specific binding (10 fmol/mg tissue) were detected in the neocortex and cerebellar cortex. The findings show that the anatomic distribution of serotonin uptake sites in the porcine brain is similar to that reported in other mammals. The density was close to that reported in human brain and in rat brain.
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Affiliation(s)
- P Cumming
- PET Center of Aarhus University Hospitals, Aarhus C, Denmark
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27
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Ase AR, Strazielle C, Hébert C, Botez MI, LaLonde R, Descarries L, Reader TA. Central serotonin system in Dystonia musculorum mutant mice: biochemical, autoradiographic and immunocytochemical data. Synapse 2000; 37:179-93. [PMID: 10881040 DOI: 10.1002/1098-2396(20000901)37:3<179::aid-syn2>3.0.co;2-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The autosomal recessive mutation dystonia musculorum (dt(J)/dt(J)) causes degenerative alterations of peripheral and central sensory pathways that lead to ataxia. To investigate possible changes in the central serotonin system of these mice, HPLC measurements of 5-hydroxytryptophan, 5-hydroxy-tryptamine (serotonin; 5-HT), and 5-HT metabolites were obtained from 22 brain regions and the spinal cord of wild type and dt(J)/dt(J) mutant mice. Also, 5-HT transporters were quantified by [(3)H]citalopram autoradiography in 72 brain regions, subregions, and nuclei, and the 5-HT innervation visualized by immunocytochemistry throughout the brain and spinal cord. In all brain regions measured for indoleamine content, there were no significant differences between the two genotypes. In the spinal cord, an increased tissue concentration of 5-HT (+34%), 5-hydroxyindole-3-acetic acid (+33%), 5-hydroxytryptophol (+21%), and 5-hydroxytryptophan (+45%) in dt(J)/dt(J) actually corresponded to the same total amount of each of these indoleamines in the entire spinal cord, when taking into account its reduced size in the mutants. Quantification of the binding to 5-HT transporters showed increases in the medial geniculate nucleus (+14%), medial (+24%) and lateral (+18%) hypothalamus, interpeduncular (+13%), vestibular (+22%), and deep cerebellar nuclei (+37%) of dt(J)/dt mice, and decreases in the ventral tegmental area (-13%), median and linear raphe nuclei (-20%), as well as in the solitary complex (-35%). There were no apparent differences in the distribution of 5-HT-immunostained fibers in these and other regions of brain and in the spinal cord of dt(J)/dt(J) compared to wild type mice. The bulk of these results indicates a relative sparing of the central 5-HT system in the dt(J)/dt(J) mice, even though alterations in 5-HT transporters could justify attempts at improving the sensorimotor dysfunction by administration of serotoninergic agents in these mice.
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Affiliation(s)
- A R Ase
- Centre de recherche en sciences neurologiques, Faculté de médecine, Université de Montréal, Montréal (Qc) H3C 3J7 Canada
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Cheetham SC, Viggers JA, Slater NA, Heal DJ. Sibutramine does not decrease the number of 5-HT re-uptake sites in rat brain and, like fluoxetine, protects against the deficits produced by dexfenfluramine. Neuropharmacology 2000; 39:2028-35. [PMID: 10963746 DOI: 10.1016/s0028-3908(00)00032-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The effect of sibutramine and dexfenfluramine on 5-HT re-uptake sites, labelled with [(3)H]paroxetine, have been determined in various rat brain regions. In addition, the ability of fluoxetine and sibutramine to protect against the changes in [(3)H]paroxetine binding produced by dexfenfluramine was examined. Sibutramine (9 mg/kg, p.o.) and dexfenfluramine (1, 3 and 10 mg/kg, p.o.) were administered twice daily (before 09.00 h and after 16.00 h) for four days, followed by a 14 day drug-free period. In the protection studies, fluoxetine (10 mg/kg, i.p.) and sibutramine (9 mg/kg, p.o.) were given 1 h prior to dexfenfluramine (10 mg/kg, p.o.) using the same dosing regimen as described above. Sibutramine (9 mg/kg, p.o.; three times its ED(50) to inhibit food intake at 2 h) had no significant effect on the number or affinity of 5-HT re-uptake sites the brain regions studied. In contrast, dexfenfluramine at an equivalent dose (3 mg/kg, p.o.) significantly decreased the number of 5-HT re-uptake sites in frontal cortex (by 35%), hippocampus (by 47%) and hypothalamus (by 27%). This effect was dose-dependent with marked decreases (by 58-84%) in the number of sites following 10 mg/kg, p.o. These effects were not associated with changes in binding affinity. Fluoxetine (10 mg/kg, i.p.) completely blocked the effect of dexfenfluramine (10 mg/kg, p.o.) without having any significant effect alone. Sibutramine (9 mg/kg, p.o.) also blocked the effects of dexfenfluramine, although the reversal was only partial in frontal cortex, hippocampus and hypothalamus. Thus sibutramine, unlike dexfenfluramine, does not alter brain 5-HT re-uptake sites. Furthermore, sibutramine and fluoxetine protect against the deficits in 5-HT re-uptake sites produced by dexfenfluramine. These data provide further evidence that sibutramine is a 5-HT re-uptake inhibitor and it does not have neurotoxic potential.
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Affiliation(s)
- S C Cheetham
- BASF Pharma, Research and Development, Nottingham NG1 1GF, UK.
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29
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Ongali B, Ase AR, Hébert C, Amdiss F, Reader TA. Dopamine D(1) and D(2) receptors in the forebrain of dystonia musculorum mutant mice: an autoradiographic survey in relation to dopamine contents. Synapse 2000; 37:1-15. [PMID: 10842346 DOI: 10.1002/(sici)1098-2396(200007)37:1<1::aid-syn1>3.0.co;2-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Dystonia musculorum (dt(J)/dt(J)) mutant mice suffer from a degeneration of spinocerebellar tracts as well as a dystrophy of peripheral sensory tracts. This neurological mutant has been proposed as an animal model of human cerebellar ataxia, in particular of the Friedreich's type; thus, it was deemed of interest to examine the endogenous contents of dopamine (DA) and metabolites as well as the distribution of DA receptors of the D(1) and D(2) subtypes, in order to delimit the biochemical characteristics of this pathological disorder, and determine an eventual dopaminergic dysfunction in this mutant. Tissue DA and its major metabolites 3, 4-dihydroxyphenylacetic acid, homovanillic acid and 3-methoxytyramine were measured by HPLC coupled to electrochemical detection in six cortical regions, in four divisions of rostral neostriatum and two halves of caudal neostriatum, as well as in olfactory bulb, nucleus accumbens, septum, amygdala, hippocampus, thalamus, hypothalamus, brainstem, cerebellum, substantia nigra, and ventral tegmental area. The only significant difference between dt(J)/dt(J) mice and wild-type controls was an increase in hypothalamic DA contents (+47%). Quantitative autoradiography with [(3)H]SCH23390 and [(3)H]raclopride, to label D(1) and D(2) receptors, respectively, revealed only moderate changes in receptor densities in a few localized regions. In dt(J)/dt(J) mutants, D(1) receptor numbers were found to be higher in thalamus (+27%) as well as in the medio-dorsal (+16%) and in the latero-dorsal (+16%) quadrants of rostral neostriatum, while D(2) receptor densities were greater in the medio-ventral (+32%) and the latero-dorsal (+17%) quadrants. The present results indicate an overall conservation of dopaminergic functions, albeit the few localized sites of increased D(1) and D(2) receptor densities, and that are seemingly independent of the DA innervation pattern, as revealed by the tissue measurements of DA and metabolites. They also rule out a major pathology linked to deficits in DA neurotransmission, and validate this mutant as an animal model of human cerebellar ataxia, probably of the Friedreich type.
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Affiliation(s)
- B Ongali
- Centre de Recherche en Sciences Neurologiques, Département de Physiologie, Faculté de Médecine, Université de Montréal, Canada
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30
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Doherty MD, Pickel VM. Ultrastructural localization of the serotonin 2A receptor in dopaminergic neurons in the ventral tegmental area. Brain Res 2000; 864:176-85. [PMID: 10802024 DOI: 10.1016/s0006-8993(00)02062-x] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Serotonin (5-hydroxytryptamine, 5-HT) 2A receptor antagonists are clinically effective antipsychotics that may differentially target mesocortical and mesolimbic dopaminergic neurons having partially segregated distribution in the parabrachial (PB) and paranigral (PN) ventral tegmental area (VTA). We examined the ultrastructural immunocytochemical localization of the 5-HT2A receptor in these subdivisions of rat VTA, to determine (1) the functional sites for receptor activation, and (2) cellular associations between the receptor and dopaminergic neurons identified by their content of tyrosine hydroxylase (TH). The mean area density of neuronal profiles containing 5-HT2A receptor labeling was not significantly different in the PB and PN VTA. In each region approximately 44% of the 5-HT2A labeled profiles were dendrites while the remainder were mainly axons. Dendritic 5-HT2A-immunoreactivity was often localized to membranous cytoplasmic organelles resembling smooth endoplasmic reticulum, and to more rarely to segments of the plasma membrane beneath contacts from unlabeled axon terminals. 5-HT2A labeling was also seen within the cytoplasm of a few axon initial segments and many small unmyelinated axons. Approximately 40% of the 5-HT2A-labeled dendritic profiles contained TH in either PB or PN VTA. Our results suggest that 5-HT2A receptors in VTA are largely cytoplasmic and play an equally important role in modulating dopaminergic neurons in PB and PN VTA. These results also implicate 5-HT2A receptors in the postsynaptic activation of non-dopaminergic neurons and possibly the presynaptic release from terminals of axons originating in, or passing through, these regions.
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Affiliation(s)
- M D Doherty
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, 411 East 69th Street, New York, NY, USA.
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31
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Charnay Y, Cusin I, Vallet PG, Muzzin P, Rohner-Jeanrenaud F, Bouras C. Intracerebroventricular infusion of leptin decreases serotonin transporter binding sites in the frontal cortex of the rat. Neurosci Lett 2000; 283:89-92. [PMID: 10739882 DOI: 10.1016/s0304-3940(00)00951-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We demonstrate that chronic intracerebroventricular infusion of leptin dramatically decreases the number of [(3)H]paroxetine binding sites in the frontal cortex of the rat brain. In contrast, the density in paroxetine binding sites estimated in the region containing raphe projecting cell bodies (i.e., the dorsal and median raphe nuclei) remains unchanged. Since leptin treatment significantly decreases food intake, [(3)H]paroxetine binding parameters were also estimated in the frontal cortex of pair-fed control rats. No significant difference in [(3)H]paroxetine binding was observed between pair-fed and ad libitum fed control rats. These data indicate that leptin treatment could regionally down-regulate serotonin transporter binding sites in the brain. Although the cellular and molecular mechanisms underlying such an effect of leptin need further investigation, our observations support the notion of a possible interaction between leptin and the serotonergic system of potential interest in the pathophysiology of depression.
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Affiliation(s)
- Y Charnay
- Division de Neuropsychiatrie, Belle-Idée, H.U.G, Ch. du Petit-Bel-Air 2, CH-1225 Chêne-, Bourg, Switzerland.
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32
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Le Marec N, Hébert C, Botez MI, Botez-Marquard T, Marchand L, Reader TA. Serotonin innervation of Lurcher mutant mice: basic data and manipulation with a combination of amantadine, thiamine and L-tryptophan. Brain Res Bull 1999; 48:195-201. [PMID: 10230710 DOI: 10.1016/s0361-9230(98)00164-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Lurcher (Lc/+) mutant mouse is characterized by a considerable atrophy of the cerebellum due to a massive loss of cerebellar Purkinje and granule cells, as well as of neurons from the inferior olivary nucleus. In this study the effects of a therapeutic combination of amantadine, thiamine and L-tryptophan on the serotonin (5-HT) innervation was assessed in Lurcher mice by autoradiography, using [3H]citalopram to label 5-HT transporters. In wild type mice as well as in both saline-treated and drug-treated Lurcher mutants, [3H]citalopram binding remained unchanged in forebrain and brainstem regions. In the cerebellum, labelling of deep cerebellar nuclei (CBnuc) was about twofold higher than in the cortex (CBctx). In saline-treated Lurcher mutants compared to wild type mice, the densities of [3H]citalopram were 98% higher in CBctx, and 180% higher in CBnuc. In CBctx of drug-treated Lurcher mutants, transporter densities were 89% higher than in the wild type, but did not differ from the saline-treated Lurcher. In the CBnuc of the drug-treated Lurcher mutants, [3H]citalopram binding was 50% higher than in the saline-treated Lurcher group, and 320% higher than in wild type mice. The results show that 5-HT transporters, already upregulated in the CBnuc of Lurcher mutant mice, can be further increased by a pharmacological treatment, possibly altering the availability of 5-HT in some of its target areas.
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Affiliation(s)
- N Le Marec
- Centre for Research in Neurological Sciences, Department of Physiology, Faculty of Medicine, University of Montréal, CHUM--Hôtel-Dieu Hospital, Québec, Canada
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Thiriet N, Humblot N, Burgun C, Aunis D, Zwiller J. Cocaine and fluoxetine induce the expression of the hVH-5 gene encoding a MAP kinase phosphatase. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1998; 62:150-7. [PMID: 9813294 DOI: 10.1016/s0169-328x(98)00226-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A novel class of immediate early genes that encode enzymes of the MAP kinase phosphatase family has recently been described. These enzymes are dual-specificity protein phosphatases and some show tissue-specific distribution, like the hVH-5 gene (homologue of vaccinia virus H1 phosphatase gene clone 5), which is expressed predominantly in the adult brain. In this paper, we investigated whether the hVH-5 gene is induced by psychostimulants in rat brain, as has been demonstrated for immediate early genes encoding transcription factors. Using in situ hybridization, we found that i.p. injection of cocaine, amphetamine and caffeine induced hVH-5 mRNA expression within 40 min in the nucleus accumbens (NAc), caudate putamen, frontal cortex and hippocampus, with a maximal effect in the NAc. The cocaine-induced hVH-5 gene induction involves the serotonergic system, since it was abolished in the NAc by lesioning serotonergic raphé projections with 5,7-dihydroxytryptamine. Moreover, the effect of cocaine was fully mimicked by the selective serotonin uptake inhibitor fluoxetine. In contrast to what has been described for c-fos and egr-1 immediate early genes, we found that hVH-5 mRNA expression in the NAc and hippocampus was as significant after repeated cocaine injections for 10 days as after a single injection. The considerable and prolonged induction of the MAP kinase phosphatase hVH-5 gene by psychostimulant drugs in postmitotic brain cells, particularly in the NAc, could indicate that MAP kinase substrates are involved in the reinforcing properties of drugs of abuse.
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Affiliation(s)
- N Thiriet
- INSERM U338, Centre de Neurochimie, 5 rue Blaise Pascal, 67084, Strasbourg, France
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34
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Del Bigio MR, Bruni JE, Vriend JP. Monoamine neurotransmitters and their metabolites in the mature rabbit brain following induction of hydrocephalus. Neurochem Res 1998; 23:1379-86. [PMID: 9814548 DOI: 10.1023/a:1020798622692] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Functional and behavioral disturbances associated with hydrocephalus may be due in part to altered neurotransmitter function in the brain. Hydrocephalus was induced in adult rabbits by injection of silicone oil into the cisterna magna. These and controls were killed 3 days, 1 and 4 weeks post-injection. Tissue concentrations of norepinephrine, epinephrine, serotonin, dopamine, and the metabolites 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), and 3,4-dihydroxyphenylacetic acid (DOPAC) levels were determined in fifteen brain regions using HPLC. There were decreases in hypothalamic and medullary dopamine, transient decreases in basal ganglia serotonin, increases in thalamic noradrenaline, and increases in hypothalamic and thalamic epinephrine. Changes in the primary neurotransmitters may be attributable to damage of their axonal projection systems. Metabolite concentrations increased in the cerebrum. Reduced clearance of extracellular fluid which accompanies cerebrospinal fluid stasis may explain the accumulation of metabolites.
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Affiliation(s)
- M R Del Bigio
- Department of Pathology, University of Manitoba, Winnipeg, Canada.
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35
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Zhou FC, Tao-Cheng JH, Segu L, Patel T, Wang Y. Serotonin transporters are located on the axons beyond the synaptic junctions: anatomical and functional evidence. Brain Res 1998; 805:241-54. [PMID: 9733975 DOI: 10.1016/s0006-8993(98)00691-x] [Citation(s) in RCA: 138] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The serotonin (5-HT) transporter (5-HTT) is known to play a role in depression and many 5-HT related diseases, and is the target site for drugs of abuse, such as cocaine, MDMA, and methamphetamine. The major role of the 5-HTT has long been considered to be to inactivate serotonin transmission through the elimination of serotonin at release sites. However, immunocytochemistry using an antibody against the N-terminal of the 5-HTT at the light microscopic (LM) level indicates that the 5-HTT is associated not only with 5-HT varicosities but also with axons. Electron microscopy (EM) reveals that the majority of the 5-HTTs exist on the axolemma outside the synaptic junctions. In studying whether axonal 5-HTTs are involved in the uptake of 5-HT, we found with autoradiography that [3H]citalopram bound to all major 5-HT fibers, not only in the terminal regions, but also in 5-HT axonal bundles such as the cingulum bundle and medial forebrain bundle. Furthermore, voltammetry recordings indicated that serotonin axonal bundles were actively engaged in high affinity serotonin uptake. The evidence indicates that 5-HTTs on 5-HT axons away from the synapse are likely to be functional in a manner similar to the terminal 5-HTT for serotonin uptake. It also suggests that the role of the 5-HTT may not only be for the termination of synaptic transmission, but also for the regulation of 5-HT through extrasynaptic (volume) transmission. Our findings may also impact the understanding of the sites of action of selective serotonin reuptake inhibitors and drug entry into serotonin neurons via the numerous axonal sites.
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Affiliation(s)
- F C Zhou
- Department of Anatomy and Medical Neurobiology Program, Indiana University School of Medicine, 635 Barnhill Drive, Indianapolis, IN 46202, USA.
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36
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Le Marec N, Hébert C, Amdiss F, Botez MI, Reader TA. Regional distribution of 5-HT transporters in the brain of wild type and 'Purkinje cell degeneration' mutant mice: a quantitative autoradiographic study with [3H]citalopram. J Chem Neuroanat 1998; 15:155-71. [PMID: 9797073 DOI: 10.1016/s0891-0618(98)00041-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The neurological mutant 'Purkinje cell degeneration' (pcd) is characterized by a primary degeneration of Purkinje cells, as well as by retrograde and secondary partial degeneration of cerebellar granule cells and inferior olivary neurons, and can be considered as an animal model of human degenerative ataxias. The serotonin (5-HT) innervation was examined in wild type and pcd mice, by quantifying 5-HT uptake sites, or transporters, using [3H]citalopram binding autoradiography. In both wild type and pcd mutants, the highest densities of 5-HT transporters were in mesencephalic and rostral pontine regions, in limbic structures, in hypothalamus and in discrete thalamic divisions, while the lowest labelling was found in cerebellum and brainstem reticular formation. In pcd mice, although [3H]citalopram labelling was higher in cerebellar cortex and deep cerebellar nuclei, when binding densities were corrected for surface area, the up-regulation of 5-HT transporters was present only in deep cerebellar nuclei. Also, higher labelling was found in nuclei raphe dorsalis and medialis, in ventral divisions of rostral neostriatum, caudal neostriatum, rostral globus pallidus, posteromedial amygdaloid nucleus, septum, olfactory tubercles, vertical limb of Broca's diagonal band, periventricular, latero-ventral and medio-ventral thalamic nuclei, medial geniculate nucleus, anterior hypothalamus and entorhinal cortex. The results indicate a relative integrity of the 5-HT innervation, but with a reorganization of serotoninergic terminals in the cerebellum, in particular in the deep cerebellar nuclei. This suggests that in progressive cerebellar degeneration, as found in the pcd mutant, the modified 5-HT system may still participate in motor functions by exerting an overall modulation of excitatory amino acid neurotransmission, but the availability of 5-HT may be altered in defined brain targets, as is the case for other spontaneous cerebellar mutants, in particular for the 'Lurcher' mutant mouse, a model of human olivopontocerebellar atrophy.
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Affiliation(s)
- N Le Marec
- Centre de Recherche en Sciences Neurologiques, Département de Physiologie, Faculté de Médecine, Université de Montréal, Qué., Canada
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37
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Quantitative evaluation of 5-hydroxytryptamine (serotonin) neuronal release and uptake: an investigation of extrasynaptic transmission. J Neurosci 1998. [PMID: 9634551 DOI: 10.1523/jneurosci.18-13-04854.1998] [Citation(s) in RCA: 207] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Whether neurotransmitters are restricted to the synaptic cleft (participating only in hard-wired neurotransmission) or diffuse to remote receptor sites (participating in what has been termed volume or paracrine transmission) depends on a number of factors. These include (1) the location of release sites with respect to the receptors, (2) the number of molecules released, (3) the diffusional rate away from the release site, determined by both the geometry near the release site as well as binding interactions, and (4) the removal of transmitter by the relevant transporter. Fast-scan cyclic voltammetry allows for the detection of extrasynaptic concentrations of many biogenic amines, permitting direct access to many of these parameters. In this study the hypothesis that 5-hydroxytryptamine (5-HT) transmission is primarily extrasynaptic in the substantia nigra reticulata, a terminal region with identified synaptic contacts, and the dorsal raphe nucleus, a somatodendritic region with rare synaptic incidence, was tested in brain slices prepared from the rat. Using carbon fiber microelectrodes, we found the concentration of 5-HT released per stimulus pulse in both regions to be identical when elicited by single pulse stimulations or trains at high frequency. 5-HT efflux elicited by a single stimulus pulse was unaffected by uptake inhibition or receptor antagonism. Thus, synaptic efflux is not restricted by binding to intrasynaptic receptors or transporters. The number of 5-HT molecules released per terminal was estimated in the substantia nigra reticulata and was considerably less than the number of 5-HT transporter and receptor sites, reinforcing the hypothesis that these sites are extrasynaptic. Furthermore, the detected extrasynaptic concentrations closely match the affinity for the predominant 5-HT receptor in each region. Although they do not disprove the existence of classical synaptic transmission, our results support the existence of paracrine neurotransmission in both serotonergic regions.
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Abstract
Drugs of abuse modify signaling of neurotransmitter systems and intracellular messengers. Recent studies of central nervous system development show that these same neurotransmitters may serve as molecules that regulate specific aspects of cell proliferation, survival, migration, circuit formation and establishment of topography. Moreover, the convergence of neurotransmitter, growth factor and hormone activity on similar intracellular signaling systems suggests the potential for significant interactions among molecular components that regulate development. The application of modern strategies used by developmental and cell biologists to the question of whether prenatal drug exposure alters brain structure and function has led to discoveries of specific, targeted changes. Studies of the mechanisms of drug action that lead to altered neural development are now reality.
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Affiliation(s)
- P Levitt
- Department of Neurobiology, University of Pittsburgh, School of Medicine, PA 15261, USA. plevitt+@pitt.edu
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39
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Abstract
The objectives of this study were to further characterize the effects of a chronic lithium (Li+) treatment on serotonin (5-HT) uptake sites, and to determine the eventual reversibility of the observed effects. Quantitative autoradiography experiments were carried out on sections from rat brain, using [3H]citalopram to label selectively the 5-HT transporters or uptake sites. In these experiments, we were able to saturate the 5-HT transporters using an isotopic dilution of the radioligand. The lowest densities of [3H]citalopram binding were measured in all cortical regions studied, with the highest cortical labelling in the anterior cingulate cortex. The rostral neostriatum presented a moderate density of labelling, with slightly higher levels in its ventral portion. Relatively high densities were measured in the globus pallidus, hippocampus, and hypothalamus. Finally, the highest densities were found in the brain stem. Indeed, the dorsal raphe nuclei as well as the substantia nigra were characterized by very high amounts of [3H]citalopram binding. The chronic administration of Li+ increased the density of 5-HT uptake sites in cortical regions, and significant differences were observed in the frontal, temporal, and entorhinal-piriform cortices, with an elevation, albeit not significant, in the anterior cingulate region. A significant increase was also observed in the lateral hypothalamus. Since the 5-HT uptake sites were studied with saturating concentrations of citalopram, we can propose that this increase in binding densities can be attributed to an increase in the number of 5-HT transporters. Interestingly, the only modifications observed were located in regions containing nerve terminals of 5-HT neurons, while regions with cell bodies remained unaffected. Moreover, these effects were completely reversed following a recovery of 48 h without Li . Also, there were no modifications in the density of 5-HT uptake sites after only 2 days of Li+. These results, suggesting an anatomically heterogenous increase in 5-HT uptake in chronically treated rats, are in accord with clinical observations and previous reports with homogenate binding assays. Finally, the conclusions from this study further support the importance of central 5-HT synaptic transmission in the pathophysiology and treatment of human affective disorders.
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Affiliation(s)
- M Carli
- Centre de Recherche en Sciences Neurologiques, Département de Physiologie, Faculté de Médecine, Université de Montréal, Québec, Canada
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40
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Huether G, Zhou D, Schmidt S, Wiltfang J, Rüther E. Long-term food restriction down-regulates the density of serotonin transporters in the rat frontal cortex. Biol Psychiatry 1997; 41:1174-80. [PMID: 9171908 DOI: 10.1016/s0006-3223(96)00265-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The influence of feeding rats only half the amount of their normal daily intake of a complete rat chow on the affinity and the density of serotonin (5-HT) transporters was measured in membrane preparations of the frontal cortex and the midbrain by a [3H]paroxetine binding assay. In young rats (10 weeks), a significant reduction of about 30% of the Bmax values of [3H]paroxetine binding occurred in the frontal cortex after 1 and 2 weeks of restricted food intake. No starvation-induced decline of the density of 5-HT transporters was seen in the midbrain. When older rats (50 weeks) were subjected to the same 50% reduction of daily food intake for 2 weeks, no such down-regulation of the density of cortical 5-HT transporters was observed. The affinity of the 5-HT transporters, as indicated by the unchanged Kd values of [3H]paroxetine binding, was not affected by semistarvation in both regions and at both ages. The observed decline of [3H]paroxetine binding sites in the frontal cortex of young adult rats is the first demonstration of long-term regulatory phenomena of brain 5-HT transporters triggered by a physiologic stimulus.
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Affiliation(s)
- G Huether
- Department of Psychiatry, University of Göttingen, Germany
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41
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Moukhles H, Bosler O, Bolam JP, Vallée A, Umbriaco D, Geffard M, Doucet G. Quantitative and morphometric data indicate precise cellular interactions between serotonin terminals and postsynaptic targets in rat substantia nigra. Neuroscience 1997; 76:1159-71. [PMID: 9027876 DOI: 10.1016/s0306-4522(96)00452-6] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We have quantified the density of serotonin axonal varicosities, their synaptic incidence and their distribution among potential targets in the pars reticulata and pars compacta of the rat substantia nigra. Serotonin axonal varicosities, counted at the light microscopic level following in vitro [3H]serotonin uptake and autoradiography, amounted to 9 x 10(6)/mm3 in the pars reticulata and 6 x 10(6)/mm3 in the pars compacta, among the densest serotonin innervations in brain. As determined at the electron microscopic level following immunolabelling for serotonin, virtually all serotonin varicosities in the pars reticulata and 50% of those in the pars compacta formed a synapse, essentially with dendrites. The combination of serotonin immunocytochemistry with tyrosine hydroxylase immunolabelling of dopamine neurons reveals that 20% of the serotonin synaptic contacts in the pars reticulata are on dopamine dendrites and 6% are on a type of unlabelled dendrite characterized by its peculiarly high cytoplasmic content of microtubules. The comparison of the diameter of the dendritic profiles that were in synaptic contact with serotonin-immunoreactive varicosities with the diameter of all other dendritic profiles of the same type suggests that serotoninergic varicosities innervate dopamine dendrites uniformly along their length, whereas they tend to contact microtubule-filled dendrites in more proximal regions and the other, unidentified dendrites in more distal regions. Furthermore, the size of the serotonin-immunoreactive varicosities and of their synaptic junctions is significantly smaller on dopamine dendrites and larger on microtubule-filled dendrites than on other, unidentified dendrites, indicating that the nature of the postsynaptic target is an important determinant of synaptic dimensions. These data should help to clarify the role of serotonin in the nigral control of motor functions. They indicate that this dense serotonin input to the substantia nigra is very precisely organized, acting through both "non-junctional" and "junctional" modes of neurotransmission in the pars compacta, which projects to the neostriatum and the limbic system, whereas the predominant mode of serotonin transmission appears to be of the "junctional" type in the pars reticulata, where serotonin can finely control the motor output of the basal ganglia by acting on the GABA projection neurons either directly or through the local release of dopamine by dopaminergic dendrites. The data also raise the possibility that the postsynaptic targets have trophic retrograde influences on serotoninergic terminals.
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Affiliation(s)
- H Moukhles
- Département de pathologie, Faculté de médecine, Université de Montréal, Québec, Canada
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42
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Cumming P, Ljubic-Thibal V, Laliberté C, Diksic M. The effect of unilateral neurotoxic lesions to serotonin fibres in the medial forebrain bundle on the metabolism of [3H]DOPA in the telencephalon of the living rat. Brain Res 1997; 747:60-9. [PMID: 9042528 DOI: 10.1016/s0006-8993(96)01227-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We used quantitative autoradiography to measure the contribution of the 5-hydroxytryptamine (5-HT, serotonin) innervation of rat telencephalon to the synthesis of dopamine (DA) from exogenous L-DOPA. One week after stereotaxic infusions of 5,7-dihydroxy-tryptamine (5,7-DHT, 1.6 micrograms) into the right medial forebrain bundle (MFB), rats received [3H]DOPA (200 microCi,i.v.), which circulated for 90 min. The specific bindings in vitro of the 5-HT uptake site ligand [3H]citalopram and the DA uptake site ligand [125I]RTI-55 were measured in cryostat sections from the prosencephalon. In most structures ipsilateral to the lesion, [3H]citalopram specific binding was substantially reduced (50-90%). In the lateral habenula specific binding declined by only 30-40%, reflecting the presence of a 5-HT pathway deviating from the MFB at the mesencephalic flexure. [125I]RTI-55 binding in the basal ganglia was reduced by 50% on the side of the 5,7-DHT lesion, but was unperturbed in rats pretreated with desmethylimipramine (DMI). 5,7-DHT infusions decreased the synthesis of [3H]DA from [3H]DOPA in vivo in the basal ganglia by (40-90%). Pretreatment with DMI protected [3H]DA synthesis in the basal ganglia, but not in the olfactory tubercle and amygdala ipsilateral to the lesion. Whereas the 5-HT innervation does not contribute greatly to [3H]DA synthesis in the basal ganglia, a substantial proportion of [3H]DA synthesis in olfactory tubercle and amygdala requires an intact 5-HT innervation.
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Affiliation(s)
- P Cumming
- Montreal Neurological Institute, McGill University, Canada
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43
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Rosel P, Menchon JM, Oros M, Vallejo J, Cortadellas T, Arranz B, Alvarez P, Navarro MA. Regional distribution of specific high affinity binding sites for 3H-imipramine and 3H-paroxetine in human brain. J Neural Transm (Vienna) 1997; 104:89-96. [PMID: 9085196 DOI: 10.1007/bf01271297] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The binding of 3H-paroxetine and 3H-imipramine has been compared in 17 different regions of 12 human control brains. Our findings reveal that the regional distribution is similar for both radioligands and their bindings tend to be parallel in the brain. The highest binding site density was found in basal ganglia (hypothalamus Bmax 780 +/- 102 fmol/mg protein for 3H-imipramine binding and Bmax 515 approximately 83 for 3H-paroxetine binding). The lowest values were found in cortical areas (cingulate cortex 191 +/- 18.5 fmol/mg for 3H-imipramine binding and 88 +/- 7.5 fmol/mg for 3H-paroxetine binding). The Kd values for 3H-paroxetine binding to neuronal membranes were similar in all brain regions (mean +/- s.d. Kd 0.07 +/- 0.007 nM) and also for 3H-imipramine binding (mean +/- s.d. Kd 1.05 +/- 0.12 nM). As these values are the same as in platelet membrane, the results obtained indicate that both binding sites are identical in neuronal and in platelet membranes. These findings suggest that both ligands are good markers of the 5HT transporter. However, the higher affinity of 3H-paroxetine confirms that this compound is a better radioligand for the 5HT uptake site.
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Affiliation(s)
- P Rosel
- Hormone Unit, Hospital Princeps d'Espanya, Barcelona, Spain
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44
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Molina-Holgado F, Alvarez FJ, Gonzalez I, Antonio MT, Leret ML. Maternal exposure to delta 9-tetrahydrocannabinol (delta 9-THC) alters indolamine levels and turnover in adult male and female rat brain regions. Brain Res Bull 1997; 43:173-8. [PMID: 9222530 DOI: 10.1016/s0361-9230(96)00434-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Perinatal exposure to delta 9-THC has been shown to produce effects on brain development. In this study we evaluated the changes induced by maternal exposure to delta 9-THC (5 mg/kg per day) from gestational day 5 to postnatal day 24 in eight discrete brain areas on the central serotoninergic system in both adult male and female rats. These result show that maternal exposure to delta 9-THC from gestational day 5 to postnatal day 24 affects development of the various central indoleaminergic system of the offsprings brain. Perinatal exposure to delta 9-THC decreased the levels of 5-HT in hypothalamus and rostral neostriatum in exposed males, and also decreased the levels of 5-HT in ventral hippocampus, septum, and midbrain raphe nuclei in both exposed males and females. Perinatal exposure to delta 9-THC increased the levels of 5-HIAA in dorsal hippocampus, hypothalamus, septum, midbrain raphe nuclei, and rostral neostriatum in exposed males and females. We have also found differences between nonexposed males and females in several brain regions. Our results confirm a regional and sexual specificity in endogenous levels of indoleamine after perinatal delta 9-THC treatment, being the midbrain raphe nuclei the most affected area.
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Affiliation(s)
- F Molina-Holgado
- Departamento Biología Animal II, Facultad CC, Biológicas, Universidad Complutense, Madrid, Spain
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45
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Strazielle C, Lalonde R, Riopel L, Botez MI, Reader TA. Regional distribution of the 5-HT innervation in the brain of normal and lurcher mice as revealed by [3H]citalopram quantitative autoradiography. J Chem Neuroanat 1996; 10:157-71. [PMID: 8783044 DOI: 10.1016/0891-0618(96)00115-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The neurological cerebellar mutant lurcher is characterized by a primary degeneration of Purkinje cells as well as retrograde secondary partial degeneration of cerebellar granule cells and inferior olivary neurons. Since serotonin (5-HT) has been implicated in the modulation of excitatory amino acid systems of the cerebellum, the 5-HT innervation of the normal and lurcher mice was examined by quantifying uptake sites using [3H]citalopram autoradiography, and by biochemical assays of the indoles 5-HT, 5-hydroxy-L-tryptophan and 5-hydroxyindole-3-acetic acid using high-performance liquid chromatography. Comparable results were found between [3H]citalopram binding and 5-HT tissue concentrations in different brain regions. The highest [3H]citaslopram labelling was observed in defined structures of the mesencephalic and upper pontine regions, in limbic strutures, in hypothalamus and in discrete thalamic divisions, while the lowest labelling of uptake sites was documented in cerebellum and brainstem reticular formation. In lurcher mutants, the histology confirmed cell degeneration and the reduction in width, leading to 65%, 45% and 25% atrophies of total cerebellum, deep nuclei and inferior olivary nucleus, respectively. The [3H]citalopram labelling corrected for surface loss was 45% and 20% higher to cerebellar deep nuclei and red nucleus, respectively, but remained unchanged in the cerebellar cortex and inferior olivary nucleus. Moreover, higher labelling was found in nucleus raphe dorsalis, ventral tegmental area, inferior colliculus, locus coeruleus, pontine central grey and anterior thalamic nuclei, areas known to be part of cerebellar afferent and efferent systems. The present results indicate that in such pathological conditions as described for the lurcher mutant, the 5-HT system may modulate motor function not only at the level of the cerebellum, but also in other forebrain structures functionally related to the motor system.
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Affiliation(s)
- C Strazielle
- Départment de physiologie, Faculté de médecine, Université de Montréal, Canada
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46
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Minabe Y, Emori K, Ashby CR. The depletion of brain serotonin levels by para-chlorophenylalanine administration significantly alters the activity of midbrain dopamine cells in rats: an extracellular single cell recording study. Synapse 1996; 22:46-53. [PMID: 8822477 DOI: 10.1002/(sici)1098-2396(199601)22:1<46::aid-syn5>3.0.co;2-i] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In this study, we examined the effect of 5-HT depletion produced by the acute administration of para-chlorophenylalanine (PCPA) on the number of spontaneously active dopamine (DA) cells in the ventral tegmental area (VTA or A10) and substantia nigra pars compacta (SNC or A9) in the rat. We also determined the effect of PCPA administration on the spike discharge pattern of midbrain DA cells. This was accomplished using standard extracellular single cell recording techniques. The administration of PCPA (400 mg/kg, i.p., 24 h before the experiment) produced a significant decrease in the number of spontaneously active DA cells in both the A9 (52%) and A10 (63%) areas compared to controls. The burst firing analysis indicated that there was a significant increase in the mean interspike interval of A9 and A10 DA neurons in PCPA treated animals compared to controls. Furthermore, a decrease in the percentage of A10 DA neurons exhibiting a burst firing pattern and the number of bursts was observed in the PCPA treated animals compared to controls. The intravenous (i.v.) administration of 5-hydroxytryptophan (40 mg/kg) and the peripheral aromatic acid decarboxylase inhibitor benserazide (10 mg/kg) which restores 5-HT content, reversed the decrease in the number of spontaneously active A9 and A10 DA neurons, as well as the decrease in the percentage of A10 DA neurons exhibiting a bursting pattern. In contrast, the i.v. administration of benserazide (10 mg/kg) and L-DOPA (40 mg/kg) did not reverse the decrease in the number of spontaneously active midbrain DA neurons produced by PCPA treatment. The pretreatment of animals with PCPA did not alter the sensitivity of spontaneously active A9 or A10 DA cells to the intravenous administration of (+)-apomorphine (1-32 micrograms/kg) compared to controls. Overall, our results indicate that the depletion of brain 5-HT by PCPA produces a decrease in the activity of midbrain DA cells, suggesting that endogenous 5-HT is required to maintain DA tone.
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Affiliation(s)
- Y Minabe
- National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
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47
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Fichtner CG, O'Connor FL, Yeoh HC, Arora RC, Crayton JW. Hypodensity of platelet serotonin uptake sites in posttraumatic stress disorder: associated clinical features. Life Sci 1995; 57:PL37-44. [PMID: 7603291 DOI: 10.1016/0024-3205(95)00262-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We have previously reported that binding to blood platelets of paroxetine, a selective serotonin (5-HT) reuptake inhibitor which binds to 5-HT uptake sites, is decreased in patients with posttraumatic stress disorder (PTSD). Specifically, we found a lower number of platelet 3H-paroxetine binding sites (Bmax) and a lower dissociation constant (Kd) for 3H-paroxetine binding in combat veterans with PTSD compared to normal control subjects. In the current study we assessed the relationship of platelet 3H-paroxetine binding to clinical features in 41 Vietnam combat veterans with SCID-diagnosed PTSD. The results indicated that Bmax of platelet 3H-paroxetine binding was negatively correlated with both state and trait anxiety, as well as with depressive and overall PTSD symptoms. However, there was no evidence that platelet 3H-paroxetine binding differed as a function of comorbid psychiatric diagnoses including major depression, other anxiety disorders, and substance abuse in these patients.
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Affiliation(s)
- C G Fichtner
- Psychiatry Service, Veterans Affairs Medical Center, North Chicago, Illinois 60064, USA
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48
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Mrini A, Soucy JP, Lafaille F, Lemoine P, Descarries L. Quantification of the serotonin hyperinnervation in adult rat neostriatum after neonatal 6-hydroxydopamine lesion of nigral dopamine neurons. Brain Res 1995; 669:303-8. [PMID: 7712186 DOI: 10.1016/0006-8993(94)01210-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Light microscope autoradiography after uptake and storage of tritiated serotonin (5-HT) in brain slices was used to count 5-HT axon terminals (varicosities) in the 5-HT-hyperinnervated neostriatum of adult rats subjected to neonatal 6-hydroxydopamine treatment and age-matched, normal controls. After correction for incomplete autoradiographic exposure and for section thickness, the results were expressed in millions of varicosities per mm3 of tissue. Control values ranged from 4.8 in the rostral to 6.3 in the caudal neostriatum (5.8 at intermediate level), for an average of 5.6. The corresponding values in 5-HT-hyperinnervated tissue ranged from 9.7 to 7.7 (8.8 at intermediate level), for an average of 8.7 and increases of 102%, 52% and 22% above control in the rostral, intermediate and caudal neostriatum, respectively (average increase of 55%). These data confirmed the predilection of the 5-HT hyperinnervation for the rostral neostriatum and demonstrated its presence in the caudal neostriatum also.
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Affiliation(s)
- A Mrini
- Département de pathologie, Université de Montréal, Qué, Canada
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49
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Gobbi M, Regondi MC, Pompeiano M, Palacios JM, Mennini T. Differential effects of 5,7-dihydroxytryptamine-induced serotoninergic degeneration of 5-HT1A receptors and 5-HT uptake sites in the rat brain. J Chem Neuroanat 1994; 7:65-73. [PMID: 7802971 DOI: 10.1016/0891-0618(94)90008-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The time-course of 5,7-dihydroxytryptamine-induced lesions (2, 5 and 14 days after i.c.v. injection of 150 micrograms) and the effects of acute reserpine treatment (10 mg/kg, i.p., one or 5 days before scheduled death), were evaluated by autoradiography of [3H]paroxetine binding sites in the rat brain. Reserpine had no significant effect on [3H]paroxetine binding, indicating that the depletion of serotonin is not sufficient per se to alter the serotonin uptake sites in any region. Two days after the 5,7-dihydroxytryptamine lesion, [3H]paroxetine binding was already decreased in the majority of brain regions. In the caudate putamen these binding sites were significantly decreased only 14 days after the lesion, whereas the ventral tegmental area (or the enclosed median forebrain bundle), the dorsal raphe (mainly the ventral portion) and the median raphe maintained their high density of serotonin uptake sites even after 14 days. Results were similar using [3H]citalopram as ligand for the serotonin uptake sites, in the brains of rats lesioned 5 days before death; an exception was the ventral portion of the dorsal raphe, where there was a significant increase with [3H]paroxetine and a decrease with [3H]citalopram binding. In adjacent sections of the same brains we also measured [3H]8-OH-DPAT binding, confirming that it completely disappears in the dorsal raphe after the lesion. Thus, considering the extent of serotonin cell body degeneration, there appears to be a paradoxical mismatch between the excessive loss of [3H]8-OH-DPAT binding and the resistance of [3H]citalopram or [3H]paroxetine binding in the dorsal raphe, suggesting that the two binding sites may undergo adaptive regulation in surviving neurons.
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Affiliation(s)
- M Gobbi
- Istituto di Ricerche Farmacologiche Mario Negri, Milano, Italy
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50
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Fichtner CG, Arora RC, O'Connor FL, Crayton JW. Platelet paroxetine binding and fluoxetine pharmacotherapy in posttraumatic stress disorder: preliminary observations on a possible predictor of clinical treatment response. Life Sci 1994; 54:PL39-44. [PMID: 8289574 DOI: 10.1016/0024-3205(94)00592-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Recent open clinical trials have found the selective serotonin reuptake inhibitor (SSRI) fluoxetine to be beneficial in the treatment of posttraumatic stress disorder (PTSD) symptoms. We have reported previously that the binding of a newer SSRI, paroxetine, to blood platelets is decreased in PTSD patients compared to normal control subjects. In the current study, pretreatment platelet paroxetine binding data were analyzed for ten Vietnam combat veterans who were treated clinically with fluoxetine for PTSD, diagnosed on the basis of the Structured Clinical Interview for DSM-III-R. Specific binding of 3H-paroxetine is reported in terms of the dissociation constant (Kd) and the maximum density of binding sites (Bmax). Based on our previous findings we hypothesized that decreased platelet 3H-paroxetine binding would be associated with positive therapeutic response to subsequent treatment with fluoxetine. Global clinical improvement ratings, conducted blind to the biochemical data, were used to separate patients into five maximal responders and five partial responders. The results indicated that maximal responders had lower pretreatment Kd values (p = .016) and a trend toward lower pretreatment Bmax values (p = .075) than the partial responders. These preliminary findings may warrant further study of platelet SSRI binding as a possible predictor of SSRI treatment response in PTSD patients.
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Affiliation(s)
- C G Fichtner
- Department of Psychiatry, Loyola University Stritch School of Medicine, Hines, Illinois
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