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Zhang Y, Liang Y, Gu Y. The dopaminergic system and Alzheimer's disease. Neural Regen Res 2025; 20:2495-2512. [PMID: 39314145 DOI: 10.4103/nrr.nrr-d-24-00230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Accepted: 07/31/2024] [Indexed: 09/25/2024] Open
Abstract
Alzheimer's disease is a common neurodegenerative disorder in older adults. Despite its prevalence, its pathogenesis remains unclear. In addition to the most widely accepted causes, which include excessive amyloid-beta aggregation, tau hyperphosphorylation, and deficiency of the neurotransmitter acetylcholine, numerous studies have shown that the dopaminergic system is also closely associated with the occurrence and development of this condition. Dopamine is a crucial catecholaminergic neurotransmitter in the human body. Dopamine-associated treatments, such as drugs that target dopamine receptor D and dopamine analogs, can improve cognitive function and alleviate psychiatric symptoms as well as ameliorate other clinical manifestations. However, therapeutics targeting the dopaminergic system are associated with various adverse reactions, such as addiction and exacerbation of cognitive impairment. This review summarizes the role of the dopaminergic system in the pathology of Alzheimer's disease, focusing on currently available dopamine-based therapies for this disorder and the common side effects associated with dopamine-related drugs. The aim of this review is to provide insights into the potential connections between the dopaminergic system and Alzheimer's disease, thus helping to clarify the mechanisms underlying the condition and exploring more effective therapeutic options.
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Affiliation(s)
- Yuhan Zhang
- International Medical College, Chongqing Medical University, Chongqing, China
| | - Yuan Liang
- College of Pharmacy, Chongqing Medical University, Chongqing, China
| | - Yixue Gu
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, China
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Galindo-Charles L, Reyes-Legorreta C, Garduño J, Galarraga E, Tapia D, Hernández-López S. The activation of D2-like dopamine receptors increases NMDA currents in the dorsal raphe serotonergic neurons. Neurosci Lett 2024; 839:137933. [PMID: 39128818 DOI: 10.1016/j.neulet.2024.137933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 07/29/2024] [Accepted: 08/08/2024] [Indexed: 08/13/2024]
Abstract
The dorsal raphe nucleus (DRN) receives dopaminergic inputs from the ventral tegmental area (VTA). Also, the DRN contains a small population of cells that express dopamine (DRNDA neurons). However, the physiological role of dopamine (DA) in the DRN and its interaction with serotonergic (5-HT) neurons is poorly understood. Several works have reported moderate levels of D1, D2, and D3 DA receptors in the DRN. Furthermore, it was found that the activation of D2 receptors increased the firing of putative 5-HT neurons. Other studies have reported that D1 and D2 dopamine receptors can interact with glutamate NMDA receptors, modulating the excitability of different cell types. In the present work, we used immunocytochemical techniques to determine the kind of DA receptors in the DRN. Additionally, we performed electrophysiological experiments in brainstem slices to study the effect of DA agonists on NMDA-elicited currents recorded from identified 5-HT DRN neurons. We found that D2 and D3 but not D1 receptors are present in this nucleus. Also, we demonstrated that the activation of D2-like receptors increases NMDA-elicited currents in 5-HT neurons through a mechanism involving phospholipase C (PLC) and protein kinase C (PKC) enzymes. Possible physiological implications related to the sleep-wake cycle are discussed.
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Affiliation(s)
- L Galindo-Charles
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de México 04510, Mexico
| | - C Reyes-Legorreta
- Laboratorio de Neuroprotección, Instituto Nacional de Rehabilitación-LGII, Ciudad de México 14389, Mexico
| | - J Garduño
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de México 04510, Mexico
| | - E Galarraga
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México (UNAM), Ciudad de México 04510, Mexico
| | - D Tapia
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México (UNAM), Ciudad de México 04510, Mexico
| | - S Hernández-López
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Ciudad de México 04510, Mexico.
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Dagher M, Perrotta KA, Erwin SA, Hachisuka A, Iyer R, Masmanidis SC, Yang H, Andrews AM. Optogenetic Stimulation of Midbrain Dopamine Neurons Produces Striatal Serotonin Release. ACS Chem Neurosci 2022; 13:946-958. [PMID: 35312275 PMCID: PMC9040469 DOI: 10.1021/acschemneuro.1c00715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Targeting neurons with light-driven opsins is widely used to investigate cell-specific responses. We transfected midbrain dopamine neurons with the excitatory opsin Chrimson. Extracellular basal and stimulated neurotransmitter levels in the dorsal striatum were measured by microdialysis in awake mice. Optical activation of dopamine cell bodies evoked terminal dopamine release in the striatum. Multiplexed analysis of dialysate samples revealed that the evoked dopamine was accompanied by temporally coupled increases in striatal 3-methoxytyramine, an extracellular dopamine metabolite, and in serotonin. We investigated a mechanism for dopamine-serotonin interactions involving striatal dopamine receptors. However, the evoked serotonin associated with optical stimulation of dopamine neurons was not abolished by striatal D1- or D2-like receptor inhibition. Although the mechanisms underlying the coupling of striatal dopamine and serotonin remain unclear, these findings illustrate advantages of multiplexed measurements for uncovering functional interactions between neurotransmitter systems. Furthermore, they suggest that the output of optogenetic manipulations may extend beyond opsin-expressing neuronal populations.
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Affiliation(s)
- Merel Dagher
- Molecular Toxicology Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA 90095, United States
| | - Katie A. Perrotta
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, United States
| | - Sara A. Erwin
- Molecular Toxicology Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA 90095, United States
| | - Ayaka Hachisuka
- Department of Neurobiology, University of California, Los Angeles, Los Angeles, CA 90095, United States
| | - Rahul Iyer
- Department of Electrical Engineering, University of California, Los Angeles, Los Angeles, CA, 94720
| | - Sotiris C. Masmanidis
- Department of Neurobiology, University of California, Los Angeles, Los Angeles, CA 90095, United States
- Neuroscience Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA 90095, United States
- California Nanosystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, United States
| | - Hongyan Yang
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience & Human Behavior, and Hatos Center for Neuropharmacology, University of California, Los Angeles, Los Angeles, CA 90095, United States
| | - Anne M. Andrews
- Molecular Toxicology Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA 90095, United States
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095, United States
- Neuroscience Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA 90095, United States
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience & Human Behavior, and Hatos Center for Neuropharmacology, University of California, Los Angeles, Los Angeles, CA 90095, United States
- California Nanosystems Institute, University of California, Los Angeles, Los Angeles, CA 90095, United States
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Tsartsalis S, Tournier BB, Gloria Y, Millet P, Ginovart N. Effect of 5-HT2A receptor antagonism on levels of D2/3 receptor occupancy and adverse behavioral side-effects induced by haloperidol: a SPECT imaging study in the rat. Transl Psychiatry 2021; 11:51. [PMID: 33446643 PMCID: PMC7809418 DOI: 10.1038/s41398-020-01179-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 12/30/2022] Open
Abstract
Several studies suggested that 5-HT2A receptor (5-HT2AR) blockade may provide a more favorable efficacy and side-effect profile to antipsychotic treatment. We hypothesized that a combined haloperidol (a D2/3 receptor (D2/3R) antagonist) and MDL-100,907 (a 5-HT2AR antagonist) treatment would reverse the side effects and the neurochemical alterations induced by haloperidol alone and would potentialize its efficacy. We thus chronically treated male Mdr1a knock-out rats with several doses of haloperidol alone or in combination with a saturating dose of a MDL-100,907. Receptor occupancy at clinically relevant levels was validated with a dual-radiotracer in-vivo SPECT imaging of D2/3R and 5-HT2AR occupancy. Experimental tests of efficacy (dizocilpine-disrupted prepulse inhibition (PPI) of the startle reflex) and side effects (catalepsy, vacuous chewing movements) were performed. Finally, a second dual-radiotracer in-vivo SPECT scan assessed the neurochemical changes induced by the chronic treatments. Chronic haloperidol failed to reverse PPI disruption induced by dizocilpine, whilst administration of MDL-100,907 along with haloperidol was associated with a reversal of the effect of dizocilpine. Haloperidol at 0.5 mg/kg/day and at 1 mg/kg/day induced catalepsy that was significantly alleviated (by ~50%) by co-treatment with MDL-100,907 but only at 0.5 mg/kg/day dose of haloperidol. Chronic haloperidol treatment, event at doses as low as 0.1 mg/kg/day induced a significant upregulation of the D2/3R in the striatum (by over 40% in the nucleus accumbens and over 20% in the caudate-putamen nuclei), that was not reversed by MDL-100,907. Finally, an upregulation of 5-HT2AR after chronic haloperidol treatment at a moderate dose only (0.25 mg/kg/day) was demonstrated in frontal cortical regions and the ventral tegmental area. Overall, a partial contribution of a 5-HT2AR antagonism to the efficacy and side-effect profile of antipsychotic agents is suggested.
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Affiliation(s)
- Stergios Tsartsalis
- Division of Adult Psychiatry, Department of Psychiatry, Geneva University Hospitals, Geneva, Switzerland. .,Division of Psychiatric Specialties, Department of Psychiatry, Geneva University Hospitals, Geneva, Switzerland.
| | - Benjamin B. Tournier
- grid.150338.c0000 0001 0721 9812Division of Adult Psychiatry, Department of Psychiatry, Geneva University Hospitals, Geneva, Switzerland
| | - Yesica Gloria
- grid.150338.c0000 0001 0721 9812Division of Adult Psychiatry, Department of Psychiatry, Geneva University Hospitals, Geneva, Switzerland
| | - Philippe Millet
- grid.150338.c0000 0001 0721 9812Division of Adult Psychiatry, Department of Psychiatry, Geneva University Hospitals, Geneva, Switzerland ,grid.8591.50000 0001 2322 4988Department of Psychiatry, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Nathalie Ginovart
- grid.8591.50000 0001 2322 4988Department of Psychiatry, Faculty of Medicine, University of Geneva, Geneva, Switzerland ,grid.8591.50000 0001 2322 4988Department of Basic Neurosciences, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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Zhang R, Li X, Shi Y, Shao Y, Sun K, Wang A, Sun F, Liu W, Wang D, Jin J, Li Y. The effects of LPM570065, a novel triple reuptake inhibitor, on extracellular serotonin, dopamine and norepinephrine levels in rats. PLoS One 2014; 9:e91775. [PMID: 24614602 PMCID: PMC3948889 DOI: 10.1371/journal.pone.0091775] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Accepted: 02/13/2014] [Indexed: 11/19/2022] Open
Abstract
Triple reuptake inhibitors (TRIs) are currently being developed as a new class of promising antidepressants that block serotonin (5-HT), dopamine (DA) and norepinephrine (NE) transporters, thereby increasing extracellular monoamine concentrations. The purpose of this study was to investigate the effects of LPM570065, a novel TRI and a desvenlafaxine prodrug, on extracellular 5-HT, DA and NE levels in the rat striatum after acute and chronic administration relative to desvenlafaxine, using High Performance Liquid Chromatography (HPLC) and microdialysis. Acute administration was performed by providing rodents with oral solutions (0.06 mmol·kg(-1) p.o.), oral suspensions (0.06 mmol·kg(-1) p.o.) and intravenous solutions (0.04 mmol·kg(-1) i.v.) of LPM570065 and desvenlafaxine. Oral suspensions (0.06 mmol·kg(-1)·day(-1)) of the two drugs were also administered for a 14-day chronic period. HPLC analysis revealed that LPM570065 rapidly penetrated the rat striatum, converted into desvenlafaxine and exhibited larger total exposure compared with the administration of desvenlafaxine. Microdialysis revealed that acute and chronic administration of oral suspension of LPM570065 increased the 5-HT, DA and NE levels more than the relative administration of desvenlafaxine. Unlike desvenlafaxine, acute administration of an intravenous LPM570065 solution did not induce the undesirable 90% decrease in extracellular 5-HT levels. In contrast to the fully dose-dependent elevation of 5-HT induced by desvenlafaxine, the acute administration of LPM570065 showed a capped increase in extracellular 5-HT levels when combined with WAY-100635. Additionally, forced swim test demonstrated that acute and chronic administration of LPM570065 reduced the immobility time more than the relative administration of desvenlafaxine. These data suggest that LPM570065 may have greater efficacy and/or a more rapid onset of antidepressant action than desvenlafaxine and also counterbalance the harmful effects of desvenlafaxine on 5-HT neurotransmission related to 5-HT1A autoreceptors. Thus, this new class of drugs, TRIs has the potential to provide a new therapeutic mechanism for treating depression.
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Affiliation(s)
- Renyu Zhang
- School of Life Sciences, Jilin University, Changchun, Jilin Province, China
- State Key Laboratory of Long-acting and Targeting Drug Delivery System, Luye Pharmaceutical Company Limited, Yantai, Shandong Province, China
| | - Xiang Li
- School of Life Sciences, Jilin University, Changchun, Jilin Province, China
- State Key Laboratory of Long-acting and Targeting Drug Delivery System, Luye Pharmaceutical Company Limited, Yantai, Shandong Province, China
| | - Yanan Shi
- School of Life Sciences, Jilin University, Changchun, Jilin Province, China
- State Key Laboratory of Long-acting and Targeting Drug Delivery System, Luye Pharmaceutical Company Limited, Yantai, Shandong Province, China
| | - Yufeng Shao
- State Key Laboratory of Long-acting and Targeting Drug Delivery System, Luye Pharmaceutical Company Limited, Yantai, Shandong Province, China
| | - Kaoxiang Sun
- State Key Laboratory of Long-acting and Targeting Drug Delivery System, Luye Pharmaceutical Company Limited, Yantai, Shandong Province, China
- School of Pharmacy, Yantai University, Yantai, Shandong Province, China
| | - Aiping Wang
- State Key Laboratory of Long-acting and Targeting Drug Delivery System, Luye Pharmaceutical Company Limited, Yantai, Shandong Province, China
- School of Pharmacy, Yantai University, Yantai, Shandong Province, China
| | - Fengying Sun
- School of Life Sciences, Jilin University, Changchun, Jilin Province, China
| | - Wanhui Liu
- State Key Laboratory of Long-acting and Targeting Drug Delivery System, Luye Pharmaceutical Company Limited, Yantai, Shandong Province, China
- School of Pharmacy, Yantai University, Yantai, Shandong Province, China
| | - Di Wang
- School of Life Sciences, Jilin University, Changchun, Jilin Province, China
| | - Jingji Jin
- School of Life Sciences, Jilin University, Changchun, Jilin Province, China
- * E-mail: (YL); (JJ)
| | - Youxin Li
- School of Life Sciences, Jilin University, Changchun, Jilin Province, China
- State Key Laboratory of Long-acting and Targeting Drug Delivery System, Luye Pharmaceutical Company Limited, Yantai, Shandong Province, China
- School of Pharmacy, Yantai University, Yantai, Shandong Province, China
- * E-mail: (YL); (JJ)
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Maejima T, Masseck OA, Mark MD, Herlitze S. Modulation of firing and synaptic transmission of serotonergic neurons by intrinsic G protein-coupled receptors and ion channels. Front Integr Neurosci 2013; 7:40. [PMID: 23734105 PMCID: PMC3661940 DOI: 10.3389/fnint.2013.00040] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 05/03/2013] [Indexed: 11/13/2022] Open
Abstract
Serotonergic neurons project to virtually all regions of the central nervous system and are consequently involved in many critical physiological functions such as mood, sexual behavior, feeding, sleep/wake cycle, memory, cognition, blood pressure regulation, breathing, and reproductive success. Therefore, serotonin release and serotonergic neuronal activity have to be precisely controlled and modulated by interacting brain circuits to adapt to specific emotional and environmental states. We will review the current knowledge about G protein-coupled receptors and ion channels involved in the regulation of serotonergic system, how their regulation is modulating the intrinsic activity of serotonergic neurons and its transmitter release and will discuss the latest methods for controlling the modulation of serotonin release and intracellular signaling in serotonergic neurons in vitro and in vivo.
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Affiliation(s)
- Takashi Maejima
- Department of Zoology and Neurobiology, Ruhr-University Bochum Bochum, Germany
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Lin CH, Tseng YL, Huang CL, Chang YC, Tsai GE, Lane HY. Synergistic effects of COMT and TPH2 on social cognition. Psychiatry 2013; 76:273-94. [PMID: 23965265 DOI: 10.1521/psyc.2013.76.3.273] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Whether genetic factors affect social cognition, particularly emotion management, requires elucidation. This study investigates whether social cognition varies with genetic variations of COMT and tryptophan hydroxylase-2 (TPH2), which modulate dopamine and serotonin neurotransmissions respectively, and thereby emotion regulation. NIMH-recommended "managing emotions branch and 2 subtasks" of MSCEIT and six neurocognition domains, and genotypes of COMT Val158Met and TPH2 G703T were measured in 150 Han-Chinese healthy adults. Subjects carrying the M allele (M group) of COMT exceeded Val/Val homozygotes (V group) in managing emotions branch (p = 0.032) and emotional relation subtask (p = 0.037). TPH2 T/T homozygotes (T group) excelled those with the G allele (G group) in emotional management subtask (p = 0.025). Subjects with M+T variation surpassed the other 3 groups (M+G, V+T and V+G) in managing emotion branch (p = 0.002), emotional relation subtask (p = 0.023), and emotional management subtask (p = 0.002). The findings remained after control for gender, age, education, and neurocognitive functions. Synergistically, the effect size of COMT-TPH2 combination surmounted the sum of separate effect sizes of COMT and TPH2. The findings suggest that genetic variations of COMT and TPH2 have synergistic effects on social cognition in the general population.
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Affiliation(s)
- Chieh-Hsin Lin
- Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan
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Lesemann A, Reinel C, Hühnchen P, Pilhatsch M, Hellweg R, Klaissle P, Winter C, Steiner B. MPTP-induced hippocampal effects on serotonin, dopamine, neurotrophins, adult neurogenesis and depression-like behavior are partially influenced by fluoxetine in adult mice. Brain Res 2012; 1457:51-69. [DOI: 10.1016/j.brainres.2012.03.046] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Revised: 02/27/2012] [Accepted: 03/20/2012] [Indexed: 12/20/2022]
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Benninghoff J, van der Ven A, Schloesser RJ, Moessner R, Möller HJ, Rujescu D. The complex role of the serotonin transporter in adult neurogenesis and neuroplasticity. A critical review. World J Biol Psychiatry 2012; 13:240-7. [PMID: 22409535 DOI: 10.3109/15622975.2011.640941] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVES Studies on the serotonin transporter (SERT) with regard to neurogenesis and neuroplastic effects on the adult brain are scarce. This is intriguing since neurogenesis is believed to play a decisive role in modulating the effect of selective serotonin reuptake inhibitors (SSRI), which are targeting SERT. METHODS Therefore, we reviewed the current scientific literature about the influence of serotonin on neurogenesis with particular emphasis on SERT in various settings, both in vivo and in vitro. RESULTS Experiments using SERT KO (knock-out) animal models showed that SERT does not directly or indirectly influence neurogenesis in vitro, whereas compensatory mechanism seem to participate in vivo. CONCLUSION At least with regard to adult neural stem cells, the impact of serotonin (5-HT) on neuroplasticity and neurogenesis is not due to SERT-mediated effcts. Instead, serotonergic fine-tuning may be exerted by a number of other different mechanisms including endogenous production of 5-HT in adult neural stem cells, uptake of 5-HT into adult neural stem cells by other monoamine transporters, and actions of the 5-HT1A receptors present on these cells.
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Affiliation(s)
- Jens Benninghoff
- Department of Psychiatry, LMU-University of Munich, Munich, Germany.
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Juckel G, Kawohl W, Giegling I, Mavrogiorgou P, Winter C, Pogarell O, Mulert C, Hegerl U, Rujescu D. Association of catechol-O-methyltransferase variants with loudness dependence of auditory evoked potentials. Hum Psychopharmacol 2008; 23:115-20. [PMID: 18081002 DOI: 10.1002/hup.906] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE The loudness dependence of auditory evoked potentials (LDAEP) provides a measure of the central serotonergic activity. As dopamine transporter availabilities also correlate with LDAEP, a dopaminergic influence is probable. The enzyme catechol-O-methyltransferase (COMT) is involved in the inactivation of synaptic dopamine. The aim of this study was to investigate the relationship between genetic variants of the COMT gene influencing synaptic dopamine levels and the LDAEP. METHODS Rs737865 in intron 1, rs4680 coding for a Val158Met substitution and rs165599 in the 3' region were investigated in 95 carefully selected healthy subjects of German descent (41 males, 54 females). The LDAEP was calculated as a linear regression slope with stimulus intensity as independent and N1/P2-amplitude as dependent variables. RESULTS Single marker analysis showed weak associations for two single nucleotide polymorphisms (SNPs) (rs737865: CC vs. T allele carrier; rs4680: G-allele carrier vs. AA homozygotes). A-G (rs4680-rs165599) was associated with lower LDAEP scores. Accordingly, haplotype analysis with all SNPs (rs737865-rs4680-rs165599) showed that the T-A-G haplotype was associated with lower scores. CONCLUSIONS These findings support the hypothesis that the LDAEP is also influenced by dopaminergic transmission. However, replications of these very preliminary but potentially important findings in independent samples are needed.
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Affiliation(s)
- Georg Juckel
- Department of Psychiatry, Ruhr-University Bochum, Germany.
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Fulford AJ, Marsden CA. An intact dopaminergic system is required for context-conditioned release of 5-HT in the nucleus accumbens of postweaning isolation-reared rats. Neuroscience 2007; 149:392-400. [PMID: 17869434 DOI: 10.1016/j.neuroscience.2007.08.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2007] [Revised: 07/27/2007] [Accepted: 08/02/2007] [Indexed: 10/23/2022]
Abstract
We investigated the effect of the tyrosine hydroxylase inhibitor, alpha-methyl-para-tyrosine (AMPT) on extracellular dopamine and 5-HT levels in the nucleus accumbens of group- and isolation-reared rats. Microdialysis with high-performance liquid chromatography-electrochemical detection was used to quantify dopamine and 5-HT efflux in the nucleus accumbens following foot shock and in association with a conditioned emotional response (CER). Isolation- and group-reared rats received i.p. injections of either saline (0.9%) or AMPT (200 mg/kg) 15 h and 2 h prior to sampling. There was no significant difference between saline-treated isolation- or group-reared rats for basal efflux of dopamine or 5-HT, however as expected, AMPT-treatment significantly reduced dopamine efflux in both groups to an equivalent level (50-55% saline-treated controls). Exposure to mild foot shock stimulated basal dopamine efflux in saline-treated groups only, although the effect was significantly greater in isolation-reared rats. In AMPT-treated rats, foot shock did not affect basal dopamine efflux in either rearing group. Foot shock evoked a prolonged increase in 5-HT efflux in both isolation- and group-reared saline-treated rats but had no effect on 5-HT efflux in AMPT-treated rats. In response to CER, isolation-rearing was associated with significantly greater efflux of both dopamine and 5-HT in saline-treated rats, compared to saline-treated, group-reared controls. However in AMPT-treated rats, efflux of dopamine or 5-HT did not change in response to CER. These data suggest that unconditioned or conditioned stress-induced changes in 5-HT release of the nucleus accumbens are dependent upon intact catecholaminergic neurotransmission. Furthermore, as the contribution of noradrenaline to catecholamine efflux in the nucleus accumbens is relatively minor compared to dopamine, our findings suggest that dopamine efflux in the nucleus accumbens is important for the local regulation of 5-HT release in this region. Finally, these findings implicate the isolation-enhanced presynaptic dopamine function in the accumbens with the augmented ventral striatal 5-HT neurotransmission characterized by isolation-reared rats.
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Affiliation(s)
- A J Fulford
- Department of Anatomy, University of Bristol, Southwell Street, Bristol BS2 8EJ, UK.
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12
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Arias B, Serretti A, Lorenzi C, Gastó C, Catalán R, Fañanás L. Analysis of COMT gene (Val 158 Met polymorphism) in the clinical response to SSRIs in depressive patients of European origin. J Affect Disord 2006; 90:251-6. [PMID: 16356553 DOI: 10.1016/j.jad.2005.11.008] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2005] [Revised: 11/08/2005] [Accepted: 11/09/2005] [Indexed: 10/25/2022]
Abstract
INTRODUCTION AND OBJECTIVES There is convincing evidence of interactions between serotonergic and dopaminergic systems and it seems that an increase of dopamine concentration in the whole brain could be a limiting factor for the antidepressant like effect of antidepressants. The COMT gene might be a good candidate for explaining some aspects of the pharmacological response to SSRIs. METHODS The aim of our study was to analyse the Val 158 Met functional polymorphism on COMT gene and clinical response (4 weeks) and clinical remission (6/8 and 12 weeks) in two samples of depressive patients (DSM-IV) treated with SSRIs of Italian and Spanish origin. Clinical outcome was measured using 21 items Hamilton scale, weekly in the Italian sample (along 6 weeks) and monthly in the Spanish one (along 12 weeks). RESULTS No overall effect of genotype or genotypextime interaction was detected. However, we observed a genotypextime interaction on HDRS decrease for citalopram treatment (F((4.6,317.5)) = 3.38, P = 0.007) in the Spanish sample. No clear effect was observed in the Italian sample. The three samples were pooled in order to test if carrying the Met/Met genotype confers an increased risk for non-remission at 6-8 weeks. The results showed that Met/Met carriers have an odds ratio of 2.21 (95% CI [1.20-4.12]) for non-remission (chi(2) = 7.43, df = 2, P = 0.006). The Met/Met effect was not observed in response at 4th week (for all SSRI treatments) or in remission at 12th week (citalopram treatment). CONCLUSIONS COMT gene could have a small and indirect effect of clinical response to SSRIs by slowing-down the antidepressant action along the follow-up, basically in citalopram treatment.
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Affiliation(s)
- Bárbara Arias
- Unitat d'Antropologia, Departament de Biologia Animal, Facultat de Biologia, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain.
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van Hierden YM, Koolhaas JM, Kost'ál L, Výboh P, Sedlacková M, Rajman M, Juráni M, Mechiel Korte S. Chicks from a high and low feather pecking line of laying hens differ in apomorphine sensitivity. Physiol Behav 2005; 84:471-7. [PMID: 15763586 DOI: 10.1016/j.physbeh.2005.01.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2004] [Revised: 01/02/2005] [Accepted: 01/24/2005] [Indexed: 11/17/2022]
Abstract
Proactive rodents show a larger behavioral response to apomorphine (APO) than reactive copers, suggesting a more sensitive DA system in proactive individuals. Previously, chicks from a high feather pecking (HFP) and low feather pecking line (LFP) have been suggested to display a proactive and reactive coping strategy, respectively. Therefore, at approximately 4 weeks of age, the behavior of 48 LFP and 48 HFP chicks in response to an APO injection was studied using an open field. Another objective of the present study was to determine whether behavioral variation (in an open field) between HFP and LFP birds, after APO injection, is also reflected by variation of D(1) and D(2) receptor densities in the brain. Receptor binding capacities were assessed by measuring specific binding of tritiated D(1) and D(2) receptor ligands in different regions of the brain of control HFP and LFP chicks. In the present study, it is shown that indeed HFP chicks display a more enhanced behavioral response to acute APO treatment (0.5 mg/kg BW) than LFP birds in an open field. This difference was not reflected by variation of D(1) and D(2) receptor densities in the brain between both lines.
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Affiliation(s)
- Yvonne M van Hierden
- Animal Sciences Group of Wageningen UR, Division of Animal Resources Development, Research group Animal Welfare, P.O. Box 65, NL-8200, AB Lelystad, The Netherlands.
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14
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Nam E, Lee SM, Koh SE, Joo WS, Maeng S, Im HI, Kim YS. Melatonin protects against neuronal damage induced by 3-nitropropionic acid in rat striatum. Brain Res 2005; 1046:90-6. [PMID: 15882841 DOI: 10.1016/j.brainres.2005.03.053] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2004] [Revised: 03/19/2005] [Accepted: 03/29/2005] [Indexed: 11/29/2022]
Abstract
In this study, the protective effects of melatonin were evaluated against 3-nitropropionic acid (3-NP)-induced striatal neuronal damage in rats. Lesions were induced in the right striatum of Sprague-Dawley rats by stereotaxic injection with 3-NP and melatonin was intraperitoneally administered both 30 min before and 60 min after 3-NP injection. And rats continuously received melatonin daily for 3 days. As indicators of oxidative damage, lipid peroxidation and protein oxidation in the lesioned striatum were measured at 1 day after 3-NP injection. Levels of malondialdehyde (MDA) and protein carbonyl were significantly increased by 3-NP injection, but reduced in the melatonin-treated rats. Four days post-lesion, large lesions and extensive neuronal damage were produced in the 3-NP-injected striata, as revealed by 2,3,5-triphenyltetrazolium chloride (TTC) staining. In addition, marked ipsilateral rotational behavior following apomorphine challenge and a decrease of dopamine content in the lesioned striatum were observed in the 3-NP-injected rats. However, melatonin treatment significantly attenuated the 3-NP-induced neuronal damage, reduced the degree of asymmetric rotational behavior, and restored the dopamine level in the lesioned striatum. The present results indicate that melatonin effectively protects against the neuronal damage caused by 3-NP in vivo and that the neuroprotective effects of melatonin may be related to antioxidant action.
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Affiliation(s)
- Eunjoo Nam
- Department of Pharmacology, College of Medicine and Neuroscience Research Institute of Medical Research Center, Seoul National University, Korea
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15
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Balcioglu A, Zhang K, Tarazi FI. Dopamine depletion abolishes apomorphine- and amphetamine-induced increases in extracellular serotonin levels in the striatum of conscious rats: a microdialysis study. Neuroscience 2003; 119:1045-53. [PMID: 12831863 DOI: 10.1016/s0306-4522(03)00219-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We investigated how serotonergic neurotransmission was affected by 6-hydroxydopamine (6-OHDA) lesioning of the adult rat brain dopamine (DA) system. In this animal model for Parkinson's disease (PD), the effect of destroying ascending DA pathways on extracellular levels of serotonin (5-HT) and 5-HT innervation in rat striatum were examined. Profound unilateral lesions of the nigrostriatal DA pathways were made by infusing 6-OHDA unilaterally into either the right medial forebrain bundle or the right substantia nigra. At 5 weeks after lesioning extracellular levels of DA and 5-HT were determined with microdialysis and high-pressure liquid chromatography under basal conditions and after systemic injections of apomorphine or amphetamine. DA nerve-terminal destruction and 5-HT innervation were determined with quantitative autoradiography. 6-OHDA lesioning reduced extracellular levels of DA below detection limits and led to statistically significant increases in extracellular 5-HT. Apomorphine, and amphetamine, respectively increased extracellular 5-HT to 8.2- and 2.2-fold above baseline levels in intact animals; these effects were absent in 6-OHDA-lesioned animals. Basal levels of [(3)H]paroxetine binding to 5-HT transporters in caudate-putamen increased by 41% in 6-OHDA-lesioned animals. These results suggest that 6-OHDA lesioning led to hyperinnervation of 5-HT nerve terminals and increases in basal extracellular 5-HT levels, but also to an unexplained loss of apomorphine and amphetamine-induced release of 5-HT. Addressing whether this impairment has significance in the onset of PD might lead to development of new strategies to manage parkinsonian symptoms.
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Affiliation(s)
- A Balcioglu
- Neuroregeneration Laboratories, McLean Hospital, Harvard Medical School, 115 Mill Street, Belmont, MA 02478, USA.
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Tao R, Fray A, Aspley S, Brammer R, Heal D, Auerbach S. Effects on serotonin in rat hypothalamus of D-fenfluramine, aminorex, phentermine and fluoxetine. Eur J Pharmacol 2002; 445:69-81. [PMID: 12065196 DOI: 10.1016/s0014-2999(02)01751-x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Hypothalamic 5-HT (serotonin) regulates food intake, energy expenditure and bodyweight. Using in vivo microdialysis, we determined the effects of various anorectic drugs on hypothalamic extracellular 5-HT levels during the dark phase when rats predominantly feed. Phentermine and aminorex, which were originally considered to be catecholaminergic drugs, markedly increased 5-HT efflux in rat hypothalamus. Their actions were less profound than D-fenfluramine, but considerably greater than that of the selective 5-HT reuptake inhibitor, fluoxetine. This suggests that enhanced hypothalamic 5-HT function could be involved in their anorectic actions. Pharmacological characterization revealed that D-fenfluramine, aminorex and probably also phentermine potentiate synaptic 5-HT function predominantly by release, whereas fluoxetine acts exclusively by reuptake inhibition. The results also revealed that the combined actions of phentermine and D-fenfluramine on hypothalamic extracellular 5-HT levels were additive, but not synergistic. In contrast, there was a significant negative cooperative effect on extraneuronal 5-HT of combining phentermine with fluoxetine.
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Affiliation(s)
- Rui Tao
- Nelson Laboratories, Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ 08854-8082, USA
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Cartmell J, Perry KW, Salhoff CR, Monn JA, Schoepp DD. Acute increases in monoamine release in the rat prefrontal cortex by the mGlu2/3 agonist LY379268 are similar in profile to risperidone, not locally mediated, and can be elicited in the presence of uptake blockade. Neuropharmacology 2001; 40:847-55. [PMID: 11378155 DOI: 10.1016/s0028-3908(01)00034-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Our recent work (Cartmell et al., Journal of Neurochemistry, 75 (2000) 1147-1154) demonstrated that systemic injection of the potent, selective mGlu2/3 receptor agonist, LY379268, acutely increased extracellular levels of dopamine, its metabolites DOPAC and HVA, and the 5-HT metabolite, 5-HIAA, in rat medial prefrontal cortex (mPFC). Here, we compared the acute effects of LY379268 with those of clozapine and risperidone (atypical antipsychotics) on extracellular levels of both dopamine and 5-HT in the mPFC of freely-moving rats. Uptake blockers were included to minimize metabolism of monoamines near the probe area. One hour after injection, LY379268 (10 mg/kg s.c.), clozapine (10 mg/kg s.c.) or risperidone (1 mg/kg s.c.) maximally increased dopamine by 224, 257 and 234% of basal levels. These effects were followed by maximal increases in DOPAC and HVA levels 2 to 3.5 hours after administration. LY379268, at 3 and 10 mg/kg s.c., and risperidone (1 mg/kg s.c.) also increased dialysate 5-HT to 169, 179 and 140% of basal levels and 5-HIAA to 144, 154 and 121% of basal levels, respectively. These neurochemical changes in the mPFC could not be mimicked when LY379268 (3 or 30 microM) was administered locally via the microdialysis probe. These data demonstrate that increases in extracellular monoamines in the rat prefrontal cortex evoked acutely by the mGlu2/3 agonist, LY379268, are similar in profile to risperidone, not locally mediated, and can be elicited in the presence of uptake blockade.
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Affiliation(s)
- J Cartmell
- Lilly Research Laboratories, Eli Lilly and Company, IN Indianapolis 46285, USA
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Abstract
The aim of the present study was to investigate the effect of dopamine (DA) on the excitability of dorsal raphe nucleus (DRN) 5-hydroxytryptamine (5-HT) neurons using the patch-clamp technique in brain slices. Bath application of DA (1-300 microM) produced a concentration-dependent membrane depolarization in all 5-HT neurons examined. This effect persisted in the presence of tetrodotoxin (TTX; 1 microM) and low extracellular calcium. Moreover, blockade of ionotropic glutamate receptors with 6,7-dinitroquinoxaline-2,3-dione (DNQX) and 2-amino-5-phosphonopentanoic acid (AP5) did not prevent DA-induced depolarization, indicating that it was mediated by a direct effect of DA on 5-HT neurons. The DA-induced depolarization was not antagonized by selective alpha1-adrenergic receptor antagonists, prazosin and WB 4101, but by a nonselective DA receptor antagonist, haloperidol. In addition, the selective D2-like receptor agonist quinpirole and antagonist sulpiride mimicked and blocked DA-induced depolarization, respectively. These results indicate that DA-induced membrane depolarization in DRN 5-HT neurons is mediated by the activation of D2-like DA receptors. The DA-induced membrane depolarization and inward current were associated with an increase in membrane conductance. Examination of the current-voltage (I-V) relationship for the DA-induced inward current revealed that the amplitude of the current increased with membrane hyperpolarization and reversed polarity at a potential near -15 mV. These data suggest that DA-induced depolarization in DRN 5-HT neurons is not mediated by a decrease in potassium conductance, but most likely by the activation of a nonselective cation current.
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Affiliation(s)
- S Haj-Dahmane
- Research Institute on Addictions, University at Buffalo, SUNY at Buffalo, 1021 Main Street, Buffalo, New York 14203, USA.
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Martín-Ruiz R, Ugedo L, Honrubia MA, Mengod G, Artigas F. Control of serotonergic neurons in rat brain by dopaminergic receptors outside the dorsal raphe nucleus. J Neurochem 2001; 77:762-75. [PMID: 11331405 DOI: 10.1046/j.1471-4159.2001.00275.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We studied the control of dorsal raphe (DR) serotonergic neurons by dopaminergic transmission in rat brain using microdialysis and single unit extracellular recordings. Apomorphine (0.5-3.0 mg/kg s.c.) and quinpirole (0.5 mg/kg s.c.) increased serotonin (5-HT) output in the DR and (only apomorphine) in striatum. These effects were antagonized by 0.3 mg/kg s.c. SCH 23390 (in DR and striatum) and 1 mg/kg s.c. raclopride (in DR). 5-HT(1A) receptor blockade potentiated the 5-HT increase produced by apomorphine in the DR. Apomorphine (50-400 microg/kg i.v.) increased the firing rate of most 5-HT neurons, an effect prevented by SCH 23390 and raclopride. Quinpirole (40-160 microg/kg i.v.) also enhanced the firing rate of 5-HT neurons. When applied in the DR, neither drug increased the 5-HT output in the DR or striatum. Likewise, micropressure injection of quinpirole (0.2-8 pmol) failed to increase the firing rate of 5-HT neurons. In situ hybridization showed that the dopamine (DA) D(2) receptor transcript was almost absent in the DR and abundant in the substantia nigra (SN) and the periaqueductal grey matter (PAG). Using dual probe microdialysis, the application of tetrodotoxin or apomorphine in SN significantly increased the DR 5-HT output. Thus, the discrepancy between local and systemic effects of dopaminergic agonists and the absence of DA D(2) receptor transcript in 5-HT neurons suggest that DA D(2) receptors outside the DR control serotonergic activity.
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Affiliation(s)
- R Martín-Ruiz
- Department of Neurochemistry, Institut d'Investigacions Biomèdiques de Barcelona, CSIC (IDIBAPS), Barcelona, Spain
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Rahman S, Engleman E, Simon J, McBride WJ. Negative interaction of dopamine D2 receptor antagonists and GBR 12909 and GBR 12935 dopamine uptake inhibitors in the nucleus accumbens. Eur J Pharmacol 2001; 414:37-44. [PMID: 11230993 DOI: 10.1016/s0014-2999(01)00785-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The objective of this study was to examine the interaction of dopamine D2 receptor antagonists and dopamine uptake inhibitors on the regulation of extracellular dopamine release in the nucleus accumbens of Wistar rats employing in vivo microdialysis and in vitro dopamine uptake studies. Application of the D2 receptor antagonists raclopride (100 microm) or sulpiride (100 microm) alone through the microdialysis probe in the nucleus accumbens for 60 min increased the extracellular levels of dopamine in the nucleus accumbens to 150% and 200% of basal, respectively. Perfusion of the nucleus accumbens for 60 min with the dopamine uptake inhibitors, 1-[2-[bis(4-Fluorophenyl)methoxy]ethyl]-4-[3-phenylpropyl]piperazine dihydrochloride (GBR 12909; 100 microm) or 1-[2-(Diphenylmethoxy)ethyl]-4-(3-phenylpropyl)-piperazine dihydrochloride (GBR 12935; 100 microm) alone, increased the extracellular levels of dopamine in the nucleus accumbens to 400% and 350% of basal, respectively. Co-perfusion of 100 microM GBR 12909 or GBR 12935 with either 100 microM sulpiride or raclopride produced a significant reduction in the GBR 12909 or GBR 12935 induced increase in the extracellular levels of dopamine to basal levels. In vitro, GBR 12909 (1-9 nM) dose-dependently inhibited active uptake of [3H]dopamine in homogenates of the nucleus accumbens. Addition of 100 microm sulpiride had little effect on GBR 12909 inhibition of [3H] dopamine uptake, suggesting that dopamine D2 receptor antagonists are not blocking the actions of the GBR-type dopamine uptake inhibitors at the dopamine transporter. Overall, the data suggest that complex interactions occur in vivo between D2 antagonists and GBR-type dopamine uptake inhibitors, which negate their effects on elevating the extracellular levels of dopamine in the nucleus accumbens.
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Affiliation(s)
- S Rahman
- Department of Psychiatry, Institute of Psychiatric Research, 791 Union Drive, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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21
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Rahman S, Engleman E, Simon J, McBride WJ. Negative interaction of dopamine D2 receptor antagonists and GBR 12909 and GBR 12935 dopamine uptake inhibitors in the nucleus accumbens. Eur J Pharmacol 2001. [DOI: https://doi.org/10.1016/s0014-2999(01)00785-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abellán MT, Martín-Ruiz R, Artigas F. Local modulation of the 5-HT release in the dorsal striatum of the rat: an in vivo microdialysis study. Eur Neuropsychopharmacol 2000; 10:455-62. [PMID: 11115735 DOI: 10.1016/s0924-977x(00)00118-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Using in vivo microdialysis in freely moving rats, we examined the involvement of major striatal transmitters on the local modulation of the 5-HT release. Tetrodotoxin reduced the striatal 5-HT output to 15-20% of baseline. The selective 5-HT(1B) receptor agonist CP 93129 (50 microM) reduced (50%) and the 5-HT(2A/2C) receptor agonist DOI (1-100 microM) increased (220%) the 5-HT output. Neither GABA nor baclofen (100 nM-100 microM) altered the 5-HT output. The glutamate reuptake inhibitor L-trans-PDC (1-4 mM) raised 5-HT to 280% of baseline. This effect was not antagonized by the NMDA receptor antagonist MK-801 (0.5 mg/kg i.p.). Local MK-801 (10-100 microM) did not significantly alter the 5-HT output. Finally, neither carbachol (10-100 microM) nor quipirole (10 microM-1 mM) affected 5-HT. These data suggest that the striatal 5-HT release is influenced by local serotonergic and glutamatergic (but not GABAergic) inputs.
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Affiliation(s)
- M T Abellán
- Department of Neurochemistry, Institut d'Investigacions Biomèdiques de Barcelona, CSIC (IDIBAPS), Rosselló 161, 6th Floor, 08036, Barcelona, Spain
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Lucas G, De Deurwaerdère P, Porras G, Spampinato U. Endogenous serotonin enhances the release of dopamine in the striatum only when nigro-striatal dopaminergic transmission is activated. Neuropharmacology 2000; 39:1984-95. [PMID: 10963742 DOI: 10.1016/s0028-3908(00)00020-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this study, we use in vivo microdialysis to investigate the influence of endogenous serotonin (5-HT) on striatal dopamine (DA) and 5-hydroxyidoleacetic acid (5-HIAA) efflux in both basal and activated conditions. The selective serotonin reuptake inhibitors citalopram and fluoxetine were used to mobilize endogenous 5-HT. In halothane-anaesthetized rats, citalopram (5 mg/kg, i.p.), administered either alone or in combination with the 5-HT(1A) receptor antagonist WAY 100635 (0.1 mg/kg, s.c.), while reducing striatal 5-HIAA outflow (-25 and -15%, respectively), had no effect on basal DA output. When locally applied into the striatum, citalopram had no effect at 1 microM concentration, but enhanced DA release after its perfusion at 25 and 100 mircroM concentrations (+27% and +67%, respectively). However, the injection of the neurotoxin 5,7-dihydroxytryptamine into the dorsal raphe nucleus, which markedly depleted 5-HT in the striatum, failed to modify the effect of 25 microM citalopram. In freely-moving rats, the intrastriatal infusion of citalopram or fluoxetine (1 microM each), had no effect on its own, but significantly enhanced the increase in DA outflow induced by the subcutaneous administration of 0.01 mg/kg haloperidol (+31% and +30% for citalopram and fluoxetine, respectively). These findings indicate that, in the striatum, endogenous 5-HT has no influence on DA release under basal conditions, but positively modulates DA outflow when nigro-striatal DA transmission is activated.
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Affiliation(s)
- G Lucas
- Laboratoire de Neuropsychobiologie des Désadaptations, UMR-CNRS 5541, Université Victor Segalen Bordeaux 2, Boîte Postale 31, 146, rue Léo Saignat, 33076 Bordeaux Cedex, France
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Lucas G, Spampinato U. Role of striatal serotonin2A and serotonin2C receptor subtypes in the control of in vivo dopamine outflow in the rat striatum. J Neurochem 2000; 74:693-701. [PMID: 10646521 DOI: 10.1046/j.1471-4159.2000.740693.x] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This study investigated, using in vivo microdialysis in the striatum of freely moving rats, the role of striatal serotonin2A (5-HT2A) and 5-HT2C receptor subtypes in the modulation of dopamine (DA) and 3, 4-dihydroxyphenylacetic acid (DOPAC) outflow, both in basal conditions and under activation induced by subcutaneous administration of 0.01 mg/kg haloperidol. The different 5-HT2 agents used were applied intrastriatally at a 1 microM concentration through the microdialysis probe. Basal DA efflux was enhanced (27%) by the 5-HT2A/2B/2C agonist 1-(4-iodo-2,5-dimethoxyphenyl)-2-aminopropane (DOI) and reduced (-30%) by the 5-HT2B/2C antagonist SB 206553. It was unaffected by infusion of the 5-HT2A antagonist SR 46349B. The effect of DOI was abolished by SB 206553 but not modified by SR 46349B. Haloperidol-stimulated DA efflux (65-70%) was reduced by both SR 46349B (-32%) and the 5-HT2A/2B/2C antagonist ritanserin (-30%) but not affected by SB 206553. Conversely, the effect of haloperidol was potentiated (22%) when DOI was coperfused with SB 206553. Also, haloperidol-stimulated DOPAC outflow (40-45%) was reduced (-20%) by SR 46349B and potentiated (25%) by the combination of SB 206553 with DOI. These results indicate that striatal 5-HT2A receptors, probably through activation of DA synthesis, positively modulate DA outflow only under activated conditions. In contrast, striatal 5-HT2C receptors exert a facilitatory control on basal DA efflux, which appears to be both tonic and phasic.
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Affiliation(s)
- G Lucas
- Laboratoire de Neuropsychobiologie des Désadaptations, UMR-CNRS 5541, Université Victor Segalen Bordeaux 2, France
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Mendlin A, Martín FJ, Jacobs BL. Dopaminergic input is required for increases in serotonin output produced by behavioral activation: an in vivo microdialysis study in rat forebrain. Neuroscience 1999; 93:897-905. [PMID: 10473255 DOI: 10.1016/s0306-4522(99)00213-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Previous research has demonstrated that pharmacological stimulation of postsynaptic dopamine D2 receptors produces increases in serotonin output. The present study explored whether this relationship also holds under physiological conditions. Accordingly, we examined the effects of D2 receptor blockade or unilateral dopamine depletion on behaviorally induced increases in extracellular serotonin levels in the corpus striatum and prefrontal cortex of freely moving rats using in vivo microdialysis. Extracellular levels of dopamine and serotonin, as well as behavioral activity, were increased by both mild tail pinch and the light-dark transition. Tail pinch-induced increases in serotonin levels (39+/-3% and 53+/-5% in the corpus striatum and prefrontal cortex, respectively), but not the accompanying behavioral changes, were blocked by local application of the D2 receptor antagonist raclopride (10 microM). D2 receptor blockade also disrupted the positive relationship between striatal serotonin levels and behavioral activity of animals across the light-dark transition (r=0.93 without raclopride, r=0.24 in presence of raclopride). Unilateral 6-hydroxydopamine lesion of the nigrostriatal dopaminergic system also abolished increases in striatal serotonin output induced by both tail pinch and light-dark transition. A negative correlation was observed between the degree of striatal dopamine depletion and tail pinch-induced increases in serotonin efflux (r= - 0.88). Thus, both a local blockade of postsynaptic D2 receptors and striatal dopamine depletion prevented increases in serotonin output that normally accompany behavioral activation. These data indicate that the increases in the forebrain serotonin output produced by two distinct physiological/environmental manipulations appear to be largely dependent upon intact local dopaminergic neurotransmission.
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Affiliation(s)
- A Mendlin
- Program in Neuroscience, Princeton University, NJ 08544-1010, USA
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Fornal CA, Martín FJ, Mendlin A, Metzler CW, Bjorvatn B, Jacobs BL. Pindolol increases extracellular 5-HT while inhibiting serotonergic neuronal activity. Eur J Pharmacol 1999; 377:187-91. [PMID: 10456429 DOI: 10.1016/s0014-2999(99)00430-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The effects of pindolol, a beta-adrenoceptor blocker/putative 5-hydroxytryptamine (5-HT)1A/1B antagonist, on both the single-unit activity of serotonergic neurons in the dorsal raphe nucleus (DRN) and extracellular 5-HT levels in the caudate nucleus, were examined in freely moving cats. Administration of (+)-pindolol (1 and 10 mg/kg, s.c.) decreased neuronal activity and increased 5-HT levels in a dose- and time-dependent manner. The subsequent administration of WAY-100635 [N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl)cycloh exanecarboxamide] (0.2 mg/kg, s.c.), a selective 5-HT1A receptor antagonist, blocked pindolol-induced neuronal suppression and potentiated 5-HT output. These results indicate that pindolol may be acting at the level of the nerve terminal to increase 5-HT.
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Affiliation(s)
- C A Fornal
- Department of Psychology, Princeton University, NJ 08544-1010, USA.
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