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Xu SY, Zhang QL, Zhang Q, Wan L, Jiang J, Tu T, Manavis J, Pan A, Cai Y, Yan XX. Regional and Cellular Mapping of Sortilin Immunoreactivity in Adult Human Brain. Front Neuroanat 2019; 13:31. [PMID: 30914927 PMCID: PMC6422922 DOI: 10.3389/fnana.2019.00031] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 02/21/2019] [Indexed: 11/16/2022] Open
Abstract
Sortilin is a member of the vacuolar protein sorting 10 protein (VPS10P) domain receptor family, which carries out signal transduction and protein transport in cells. Sortilin serves as the third, G-protein uncoupled, receptor of neurotensin that can modulate various brain functions. More recent data indicate an involvement of sortilin in mood disorders, dementia and Alzheimer-type neuropathology. However, data regarding the normal pattern of regional and cellular expression of sortilin in the human brain are not available to date. Using postmortem adult human brains free of neuropathology, the current study determined sortilin immunoreactivity (IR) across the entire brain. Sortilin IR was broadly present in the cerebrum and subcortical structures, localizing to neurons in the somatodendritic compartment, but not to glial cells. In the cerebrum, sortilin IR exhibited differential regional and laminar patterns, with pyramidal, multipolar and polymorphic neurons in cortical layers II–VI, hippocampal formation and amygdaloid complex more distinctly labeled relative to GABAergic interneurons. In the striatum and thalamus, numerous small-to-medium sized neurons showed light IR, with a small group of large sized neurons heavily labeled. In the midbrain and brainstem, sortilin IR was distinct in neurons at the relay centers of descending and ascending neuroanatomical pathways. Dopaminergic neurons in the substantia nigra, cholinergic neurons in the basal nuclei of Meynert and noradrenergic neurons in the locus coeruleus co-expressed strong sortilin IR in double immunofluorescence. In comparison, sortilin IR was weak in the olfactory bulb and cerebellar cortex, with the mitral and Purkinje cells barely visualized. A quantitative analysis was carried out in the lateral, basolateral, and basomedial nuclei of the amygdaloid complex, as well as cortical layers II–VI, which established a positive correlation between the somal size and the intensity of sortilin IR among labeled neurons. Together, the present study demonstrates a predominantly neuronal expression of sortilin in the human brain with substantial regional and cell-type variability. The enriched expression of sortilin in pyramidal, dopaminergic, noradrenergic and cholinergic neurons suggests that this protein may be particularly required for signal transduction, protein trafficking and metabolic homeostasis in populations of relatively large-sized projective neurons.
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Affiliation(s)
- Shu-Yin Xu
- Department of Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, Changsha, China
| | - Qi-Lei Zhang
- Department of Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, Changsha, China
| | - Qi Zhang
- Department of Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, Changsha, China
| | - Lily Wan
- Department of Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, Changsha, China
| | - Juan Jiang
- Department of Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, Changsha, China
| | - Tian Tu
- Department of Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, Changsha, China
| | - Jim Manavis
- SA Pathology, Schools of Medicine and Veterinary Science, Hanson Institute Centre for Neurological Diseases, The University of Adelaide, Adelaide, SA, Australia
| | - Aihua Pan
- Department of Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, Changsha, China.,Center for Morphological Sciences, School of Basic Medicine, Central South University, Changsha, China
| | - Yan Cai
- Department of Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, Changsha, China.,Department of Histology and Embryology, Xiangya School of Medicine, Central South University, Changsha, China
| | - Xiao-Xin Yan
- Department of Anatomy and Neurobiology, Xiangya School of Medicine, Central South University, Changsha, China.,Key Laboratory of Hunan Province in Neurodegenerative Disorders, Xiangya Hospital, Central South University, Changsha, China
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Ellenbroek BA, Angelucci F, Husum H, Mathé AA. Gene-environment interactions in a rat model of depression. Maternal separation affects neurotensin in selected brain regions. Neuropeptides 2016; 59:83-88. [PMID: 27372546 DOI: 10.1016/j.npep.2016.05.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 04/13/2016] [Accepted: 05/23/2016] [Indexed: 12/11/2022]
Abstract
Although the etiology of major psychiatric disorders has not been elucidated, accumulating evidence indicates that both genetic and early environmental factors play a role. We have previously demonstrated behavioral and neurochemical changes both in non-manipulated genetic rat models of depression, such as Flinders Sensitive Line (FSL) and Fawn Hooded (FH), and in normal rats following maternal separation (MS). The aim of the present study was to extend this work by exploring whether neurotensin (NT), a peptide implicated in several psychiatric disorders, is altered in a new animal model based on gene - environment interactions. More specifically, we used the FSL rats as a genetic model of depression and the Flinders Resistant Line (FRL) as controls and subjected them to MS. Pups randomly assigned to the MS procedure were separated from the dam as a litter for 180min daily between postnatal day 2 to 14. On postnatal day 90, rats were weighed and sacrificed by a two second high energy focused microwave irradiation and several brain regions were obtained by micropuncture. Neurotensin-like immunoreactivity (NT-LI) was measured by radioimmunoassay (RIA). The results showed that the FSL rats compared to the FRL rats have higher baseline NT-LI concentrations in the temporal cortex and periaqueductal gray and a markedly different response to maternal separation. The only observed change following maternal separation in the FRL rats was an NT-LI increase in the periaqueductal gray. In contrast, in the FSL significant increases were found in the nucleus accumbens, hippocampus, and entorhinal cortex and a decrease was seen in the temporal cortex after MS. The present study revealed baseline regional differences in NT-LI concentrations between the FSL and FRL strains and demonstrated that early MD differentially affects the two strains. The relevance of these alterations for depression as well as possible mechanisms underlying this gene-environment interaction are discussed.
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Affiliation(s)
- Bart A Ellenbroek
- School of Psychology, Victoria University of Wellington, Wellington, New Zealand.
| | | | - Henriette Husum
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Aleksander A Mathé
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
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Antipsychotic-like effects of a neurotensin receptor type 1 agonist. Behav Brain Res 2016; 305:8-17. [PMID: 26909848 DOI: 10.1016/j.bbr.2016.02.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Revised: 02/16/2016] [Accepted: 02/18/2016] [Indexed: 12/26/2022]
Abstract
Although neurotensin (NT) analogs are known to produce antipsychotic-like effects, the therapeutic possibility of a brain penetrant NTS1 agonist in treating psychiatric disorders has not been well studied. Here, we examined whether PD149163, a brain-penetrant NTS1-specific agonist, displays antipsychotic-like effects in C57BL/6J mice by investigating the effect of PD149163 on amphetamine-mediated hyperactivity and amphetamine-induced disruption of prepulse inhibition. In addition, we assessed the effect of PD149163 on glycogen synthase kinase-3 (GSK-3) activity, a downstream molecular target of antipsychotics and mood stabilizers, using phospho-specific antibodies. PD149163 (0.1 and 0.5mg/kg) inhibited amphetamine-induced hyperactivity in mice, indicating that NTS1 activation inhibits psychomotor agitation. PD149163 (0.5mg/kg) also increased prepulse inhibition, suggesting that NTS1 activation reduces prepulse inhibition deficits which often co-occur with psychosis in humans. Interestingly, PD149163 increased the inhibitory serine phosphorylation on both GSK-3α and GSK-3β in a dose- and time-dependent manner in the nucleus accumbens and medial prefrontal cortex of the mice. Moreover, PD149163 inhibited GSK-3 activity in the nucleus accumbens and medial prefrontal cortex in the presence of amphetamine. Thus, like most current antipsychotics and mood stabilizers, PD149163 inhibited GSK-3 activity in cortico-striatal circuitry. Together, our findings indicate that PD149163 may be a novel antipsychotic.
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Activation of neurotensin receptor 1 facilitates neuronal excitability and spatial learning and memory in the entorhinal cortex: beneficial actions in an Alzheimer's disease model. J Neurosci 2014; 34:7027-42. [PMID: 24828655 DOI: 10.1523/jneurosci.0408-14.2014] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Neurotensin (NT) is a tridecapeptide distributed in the CNS, including the entorhinal cortex (EC), a structure that is crucial for learning and memory and undergoes the earliest pathological alterations in Alzheimer's disease (AD). Whereas NT has been implicated in modulating cognition, the cellular and molecular mechanisms by which NT modifies cognitive processes and the potential therapeutic roles of NT in AD have not been determined. Here we examined the effects of NT on neuronal excitability and spatial learning in the EC, which expresses high density of NT receptors. Brief application of NT induced persistent increases in action potential firing frequency, which could last for at least 1 h. NT-induced facilitation of neuronal excitability was mediated by downregulation of TREK-2 K(+) channels and required the functions of NTS1, phospholipase C, and protein kinase C. Microinjection of NT or NTS1 agonist, PD149163, into the EC increased spatial learning as assessed by the Barnes Maze Test. Activation of NTS1 receptors also induced persistent increases in action potential firing frequency and significantly improved the memory status in APP/PS1 mice, an animal model of AD. Our study identifies a cellular substrate underlying learning and memory and suggests that NTS1 agonists may exert beneficial actions in an animal model of AD.
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Association Between Neurotensin Receptor 1 (NTR1) Gene Polymorphisms and Schizophrenia in a Han Chinese Population. J Mol Neurosci 2013; 50:345-52. [DOI: 10.1007/s12031-013-9988-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 02/26/2013] [Indexed: 11/25/2022]
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Li J, Chen C, Chen C, He Q, Li H, Li J, Moyzis RK, Xue G, Dong Q. Neurotensin receptor 1 gene (NTSR1) polymorphism is associated with working memory. PLoS One 2011; 6:e17365. [PMID: 21394204 PMCID: PMC3048867 DOI: 10.1371/journal.pone.0017365] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Accepted: 02/01/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Recent molecular genetics studies showed significant associations between dopamine-related genes (including genes for dopamine receptors, transporters, and degradation) and working memory, but little is known about the role of genes for dopamine modulation, such as those related to neurotensin (NT), in working memory. A recent animal study has suggested that NT antagonist administration impaired working memory in a learning task. The current study examined associations between NT genes and working memory among humans. METHODS Four hundred and sixty healthy undergraduate students were assessed with a 2-back working memory paradigm. 5 SNPs in the NTSR1 gene were genotyped. 5 ANOVA tests were conducted to examine whether and how working memory differed by NTSR1 genotype, with each SNP variant as the independent variable and the average accuracy on the working memory task as the dependent variable. RESULTS ANOVA results suggested that two SNPs in the NTSR1 gene (rs4334545 and rs6090453) were significantly associated with working memory. These results survived corrections for multiple comparisons. CONCLUSIONS Our results demonstrated that NTSR1 SNP polymorphisms were significantly associated with variance in working memory performance among healthy adults. This result extended previous rodent studies showing that the NT deficiency impairs the working memory function. Future research should replicate our findings and extend to an examination of other dopamine modulators.
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Affiliation(s)
- Jin Li
- National Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, People's Republic of China
- Department of Psychology and Social Behavior, University of California Irvine, Irvine, California, United States of America
| | - Chuansheng Chen
- Department of Psychology and Social Behavior, University of California Irvine, Irvine, California, United States of America
| | - Chunhui Chen
- National Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, People's Republic of China
| | - Qinghua He
- National Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, People's Republic of China
- Department of Psychology, University of Southern California, Los Angeles, California, United States of America
| | - He Li
- National Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, People's Republic of China
| | - Jun Li
- National Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, People's Republic of China
| | - Robert K. Moyzis
- Department of Biological Chemistry, University of California Irvine, Irvine, California, United States of America
| | - Gui Xue
- National Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, People's Republic of China
- Department of Psychology, University of Southern California, Los Angeles, California, United States of America
| | - Qi Dong
- National Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, People's Republic of China
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Prenatal viral infection of mice at E16 causes changes in gene expression in hippocampi of the offspring. Eur Neuropsychopharmacol 2009; 19:648-53. [PMID: 19501487 PMCID: PMC2716397 DOI: 10.1016/j.euroneuro.2009.03.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 03/04/2009] [Accepted: 03/24/2009] [Indexed: 01/30/2023]
Abstract
The hippocampus governs memory formation and emotional regulation, and there is widespread evidence of hippocampal dysfunction in psychiatric disorders, including schizophrenia and autism. There is abundant evidence that prenatal viral infection may play a role in the development of these two disorders. In the current study, we have examined gene expression and structural changes of the hippocampi of exposed neonates following maternal infection at embryonic day (E) 16 (middle second trimester). We observed significant changes in gene expression in the offspring at postnatal day (P) 0 (birth), P14 (childhood), and P56 (adulthood), including a number of candidate genes for autism and schizophrenia. qRT-PCR verified the direction and magnitude of change for 5 of the genes from the microarray data set and revealed mRNA changes for additional genes associated with schizophrenia and autism. MRI revealed a decrease in hippocampal volume at P35 (adolescence). Our results demonstrate altered gene expression and reduced hippocampal volume in the offspring following prenatal viral infection at E16.
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Prus AJ, Huang M, Li Z, Dai J, Meltzer HY. The neurotensin analog NT69L enhances medial prefrontal cortical dopamine and acetylcholine efflux: Potentiation of risperidone-, but not haloperidol-, induced dopamine efflux. Brain Res 2007; 1184:354-64. [DOI: 10.1016/j.brainres.2007.09.092] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2007] [Revised: 09/20/2007] [Accepted: 09/28/2007] [Indexed: 10/22/2022]
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Abstract
Neurotensin (NT) is a neuropeptide that, for decades, has been implicated in the biology of schizophrenia. It is closely associated with, and is thought to modulate, dopaminergic and other neurotransmitter systems involved in the pathophysiology of various neuropsychiatric diseases, including schizophrenia. This review outlines the neurochemistry and function of the NT system and the data implicating its role in schizophrenia. The data suggest that NT receptor agonists have the potential to be used as novel therapeutic agents for the treatment of schizophrenia, with the added benefits of (i) not causing weight gain, an adverse effect that is problematic with some of the currently used atypical antipsychotic drugs; and (ii) helping patients to stop smoking, a behaviour that is highly prevalent in those with schizophrenia.
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Affiliation(s)
- Mona Boules
- Neuropsychopharmacology Laboratory, Mayo Foundation for Medical Education and Research, Mayo Clinic Jacksonville, Florida 32224, USA.
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Cáceda R, Kinkead B, Nemeroff CB. Involvement of neuropeptide systems in schizophrenia: human studies. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2007; 78:327-76. [PMID: 17349866 DOI: 10.1016/s0074-7742(06)78011-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Neuropeptides are heterogeneously distributed throughout the digestive, circulatory, and nervous systems and serve as neurotransmitters, neuromodulators, and hormones. Neuropeptides are phylogenetically conserved and have been demonstrated to regulate numerous behaviors. They have been hypothesized to be pathologically involved in several psychiatric disorders, including schizophrenia. On the basis of preclinical data, numerous studies have sought to examine the role of neuropeptide systems in schizophrenia. This chapter reviews the clinical data, linking alterations in neuropeptide systems to the etiology, pathophysiology, and treatment of schizophrenia. Data for the following neuropeptide systems are included: arginine-vasopressin, cholecystokinin (CCK), corticotropin-releasing factor (CRF), interleukins, neuregulin 1 (NRG1), neurotensin (NT), neuropeptide Y (NPY), opioids, secretin, somatostatin, tachykinins, thyrotropin-releasing hormone (TRH), and vasoactive intestinal peptide (VIP). Data from cerebrospinal fluid (CSF), postmortem and genetic studies, as well as clinical trials are described. Despite the inherent difficulties associated with human studies (including small sample size, variable duration of illness, medication status, the presence of comorbid psychiatric disorders, and diagnostic heterogeneity), several findings are noteworthy. Postmortem studies support disease-related alterations in several neuropeptide systems in the frontal and temporal cortices. The strongest genetic evidence supporting a role for neuropeptides in schizophrenia are those studies linking polymorphisms in NRG1 and the CCKA receptor with schizophrenia. Finally, the only compounds that act directly on neuropeptide systems that have demonstrated therapeutic efficacy in schizophrenia are neurokinin receptor antagonists. Clearly, additional investigation into the role of neuropeptide systems in the etiology, pathophysiology, and treatment of schizophrenia is warranted.
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Affiliation(s)
- Ricardo Cáceda
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine Atlanta, Georgia 30322, USA
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Boules M, Fredrickson P, Richelson E. Neurotensin agonists as an alternative to antipsychotics. Expert Opin Investig Drugs 2006; 14:359-69. [PMID: 15882113 DOI: 10.1517/13543784.14.4.359] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Neurotensin (NT) is a 13 amino acid neuropeptide that is found in the central nervous system and in the gastrointestinal tract. In brain, this peptide is prominently associated anatomically with dopaminergic, as well as other neurotransmitter systems. Based on animal studies, already decades old, researchers have hypothesised that NT receptor agonists will have antipsychotic properties in patients. However, to date no one has obtained a non-peptide NT receptor agonist. Therefore, there has been great interest in obtaining peptide analogues of NT, that, unlike NT resist degradation by peptidases and cross the blood-brain barrier, yet have the pharmacological characteristics of native NT, for therapeutic use in the treatment of schizophrenia, as well as other neuropsychiatric diseases such as Parkinson's disease and addiction to psychostimulants. In this review, we present the rationale for development of NT receptor agonists for treatment of certain central nervous system diseases, as well as a review of those peptide agonists that are in early stages of development.
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Affiliation(s)
- Mona Boules
- Neuropsychopharmacology Laboratory and Nicotine Dependence Center, Mayo Foundation for Medical Education and Research, 4500 San Pablo Road, Jacksonville, FL 32224, USA
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Boules M, Fredrickson P, Richelson E. Bioactive analogs of neurotensin: focus on CNS effects. Peptides 2006; 27:2523-33. [PMID: 16882457 DOI: 10.1016/j.peptides.2005.12.018] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2005] [Accepted: 12/01/2005] [Indexed: 11/17/2022]
Abstract
Neurotensin (NT) is a 13-amino acid neuropeptide found in the central nervous system and in the gastrointestinal tract. It is closely associated anatomically with dopaminergic and other neurotransmitter systems, and evidence supports a role for NT agonists in the treatment of various neuropsychiatric disorders. However, NT is readily degraded by peptidases, so there is much interest in the development of stable NT agonists, that can be injected systemically, cross the blood-brain barrier (BBB), yet retains the pharmacological characteristics of native NT for therapeutic use in the treatment of diseases such as schizophrenia, Parkinson's disease and addiction.
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Affiliation(s)
- Mona Boules
- Neuropsychopharmacology Laboratory, Mayo Clinic, 4500 San Pablo Road, Jacksonville, FL 32224, USA.
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Cáceda R, Kinkead B, Nemeroff CB. Neurotensin: role in psychiatric and neurological diseases. Peptides 2006; 27:2385-404. [PMID: 16891042 DOI: 10.1016/j.peptides.2006.04.024] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2005] [Accepted: 04/01/2006] [Indexed: 10/24/2022]
Abstract
Neurotensin (NT), an endogenous brain-gut peptide, has a close anatomical and functional relationship with the mesocorticolimbic and neostriatal dopamine system. Dysregulation of NT neurotransmission in this system has been hypothesized to be involved in the pathogenesis of schizophrenia. Additionally, NT containing circuits have been demonstrated to mediate some of the mechanisms of action of antipsychotic drugs, as well as the rewarding and/or sensitizing properties of drugs of abuse. NT receptors have been suggested to be novel targets for the treatment of psychoses or drug addiction.
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Affiliation(s)
- Ricardo Cáceda
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Suite 4000 WMRB, 101 Woodruff Circle, Atlanta, GA 30322 4990, USA.
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Ikemoto K. Significance of human striatal D-neurons: implications in neuropsychiatric functions. Prog Neuropsychopharmacol Biol Psychiatry 2004; 28:429-34. [PMID: 15093949 DOI: 10.1016/j.pnpbp.2003.11.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/14/2003] [Indexed: 11/22/2022]
Abstract
The human striatum, especially its ventral part, the nucleus accumbens (Acc), contains numerous nonmonoaminergic aromatic L-amino acid decarboxylase (AADC) [=dopa decarboxylase (DDC)] neurons (D-neurons). AADC is the second-step synthesizing enzyme for monoamines and is also the rate-limiting enzyme of phenylethylamine (PEA) synthesis. D-neurons may participate in the manifestation of efficacy of pharmacotherapy for Parkinson's disease by taking up monoamine precursors including L-dopa or droxidopa (L-threo-DOPS) and by converting them to dopamine or noradrenaline, respectively. Although previous studies have shown that AADC activity was elevated in the striatum of drug-naive schizophrenia, the number of striatal D-neurons was reduced in autopsy brains of schizophrenia. It is unclear whether or not such reduction of striatal D-neurons implies downregulation. Possible pluripotentiality of D-neurons, including compensatory functions against aging and degeneration, was discussed based on recent published works.
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Affiliation(s)
- Keiko Ikemoto
- Clinical Research Institute, National Minami Hanamaki Hospital, 500 Suwa, Hanamaki, Iwate, 025-0033, Japan.
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Huezo-Diaz P, Arranz MJ, Munro J, Osborne S, Makoff A, Kerwin RW, Austin J, O'Donovan M. An association study of the neurotensin receptor gene with schizophrenia and clozapine response. Schizophr Res 2004; 66:193-5. [PMID: 15061255 DOI: 10.1016/s0920-9964(03)00128-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2003] [Accepted: 04/18/2003] [Indexed: 11/20/2022]
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