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Chen XY, Xue Y, Chen H, Chen L. The globus pallidus as a target for neuropeptides and endocannabinoids participating in central activities. Peptides 2020; 124:170210. [PMID: 31778724 DOI: 10.1016/j.peptides.2019.170210] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 11/14/2019] [Accepted: 11/21/2019] [Indexed: 12/12/2022]
Abstract
The globus pallidus in the basal ganglia plays an important role in movement regulation. Neuropeptides and endocannabinoids are neuronal signalling molecules that influence the functions of the whole brain. Endocannabinoids, enkephalin, substance P, neurotensin, orexin, somatostatin and pituitary adenylate cyclase-activating polypeptides are richly concentrated in the globus pallidus. Neuropeptides and endocannabinoids exert excitatory or inhibitory effects in the globus pallidus mainly by modulating GABAergic, glutamatergic and dopaminergic neurotransmission, as well as many ionic mechanisms. Pallidal neuropeptides and endocannabinoids are associated with the pathophysiology of a number of neurological disorders, such as Parkinson's disease, Huntington's disease, schizophrenia, and depression. The levels of neuropeptides and endocannabinoids and their receptors in the globus pallidus change in neurological diseases. It has been demonstrated that spontaneous firing activity of globus pallidus neurons is closely related to the manifestations of Parkinson's disease. Therefore, the neuropeptides and endocannabinoids in the globus pallidus may function as potential targets for treatment in some neurological diseases. In this review, we highlight the morphology and function of neuropeptides and endocannabinoids in the globus pallidus and their involvement in neurological diseases.
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Affiliation(s)
- Xin-Yi Chen
- Department of Pathology, Qingdao Municipal Hospital, Qingdao University, Qingdao, China; Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Yan Xue
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - Hua Chen
- Department of Pathology, Qingdao Municipal Hospital, Qingdao University, Qingdao, China.
| | - Lei Chen
- Department of Physiology and Pathophysiology, School of Basic Medicine, Qingdao University, Qingdao, China.
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2
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Richard T, Petit E, Pouységu L, Monti JP, Bondon A, Sylla T, Mérillon JM, Quideau S, Da Costa G. Impact of polyphenols on receptor-ligand interactions by NMR: the case of neurotensin (NT)-neurotensin receptor fragment (NTS1) complex. J Biomol Struct Dyn 2019; 38:1467-1478. [PMID: 31046599 DOI: 10.1080/07391102.2019.1608863] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Ligand-receptor interactions can be implicated in many pathological events such as chronic neurodegenerative diseases. Thus, the discovery of molecules disrupting this type of interactions could be an interesting therapeutic approach. Polyphenols are well known for their affinity for proteins and several studies have characterized these direct interactions. But studying the direct influence of multi-therapeutic drugs on a ligand-receptor complex relevant to a neurodegenerative disorder is a challenging issue. Solution NMR, molecular modeling and iterative calculations were used to obtain information about the interaction between a phenolic compound, α-glucogallin (α-2) and a ligand/fragment receptor complex neurotensin (NT) and its receptor NTS1. The α-2 was shown to bind to NT and a peptidic fragment of its NTS1 receptor, independently. Although the formation of the corresponding ligand-receptor complex did not seem to be affected, this experimental modeling protocol will enable the evaluation of other anti-amyloidogenic compounds such as blockers of NT-NTS1 binding. These types of studies help in understanding the specificity and influence in binding and can provide information to develop new molecules with a putative pharmacological interest.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Tristan Richard
- Université de Bordeaux, ISVV, EA 4577, USC 1366 INRA, Unité de Recherche OEnologie, Villenave d'Ornon, France
| | - Eva Petit
- Université de Toulouse, Institut National Polytechnique de Toulouse, Ecole d'Ingénieurs de Purpan, Unité Propre Physiologie, Pathologie et Génétique Végétales (PPGV), Toulouse, France
| | | | - Jean-Pierre Monti
- Université de Bordeaux, Laboratoire de Physique et Biophysique, Bordeaux, France
| | - Arnaud Bondon
- Université de Rennes, CNRS, ISCR - UMR 6226, Rennes, France
| | - Tahiri Sylla
- Université de Bordeaux, ISM (CNRS-UMR 5255), Talence, France
| | - Jean-Michel Mérillon
- Université de Bordeaux, ISVV, EA 4577, USC 1366 INRA, Unité de Recherche OEnologie, Villenave d'Ornon, France
| | | | - Grégory Da Costa
- Université de Bordeaux, ISVV, EA 4577, USC 1366 INRA, Unité de Recherche OEnologie, Villenave d'Ornon, France
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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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Tschumi CW, Beckstead MJ. Diverse actions of the modulatory peptide neurotensin on central synaptic transmission. Eur J Neurosci 2018; 49:784-793. [PMID: 29405480 DOI: 10.1111/ejn.13858] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 01/29/2018] [Accepted: 01/30/2018] [Indexed: 12/27/2022]
Abstract
Neurotensin (NT) is a 13 amino acid neuropeptide that is expressed throughout the central nervous system and is implicated in the etiology of multiple diseases and disorders. Many primary investigations of NT-induced modulation of neuronal excitability at the level of the synapse have been conducted, but they have not been summarized in review form in nearly 30 years. Therefore, the goal of this review is to discuss the many actions of NT on neuronal excitability across brain regions as well as NT circuit architecture. In the basal ganglia as well as other brain nuclei, NT can act through diverse intracellular signaling cascades to enhance or depress neuronal activity by modulating activity of ion channels, ionotropic and metabotropic neurotransmitter receptors, and presynaptic release of neurotransmitters. Further, NT can produce indirect effects by evoking endocannabinoid release, and recently has itself been identified as a putative retrograde messenger. In the basal ganglia, the diverse actions and circuit architecture of NT signaling allow for input-specific control of reward-related behaviors.
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Affiliation(s)
- Christopher W Tschumi
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104-5005, USA
| | - Michael J Beckstead
- Aging & Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104-5005, USA
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Zhang H, Dong H, Lei S. Neurotensinergic augmentation of glutamate release at the perforant path-granule cell synapse in rat dentate gyrus: Roles of L-Type Ca²⁺ channels, calmodulin and myosin light-chain kinase. Neuropharmacology 2015; 95:252-60. [PMID: 25842242 DOI: 10.1016/j.neuropharm.2015.03.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Revised: 03/23/2015] [Accepted: 03/24/2015] [Indexed: 01/12/2023]
Abstract
Neurotensin (NT) serves as a neuromodulator in the brain where it is involved in modulating a variety of physiological functions including nociception, temperature, blood pressure and cognition, and many neurological diseases such as Alzheimer's disease, schizophrenia and Parkinson's disease. Whereas there is compelling evidence demonstrating that NT facilitates cognitive processes, the underlying cellular and molecular mechanisms have not been fully determined. Because the dentate gyrus expresses high densities of NT and NT receptors, we examined the effects of NT on the synaptic transmission at the synapse formed between the perforant path (PP) and granule cells (GC) in the rats. Our results demonstrate that NT persistently increased the amplitude of the AMPA receptor-mediated EPSCs at the PP-GC synapse. NT-induced increases in AMPA EPSCs were mediated by presynaptic NTS1 receptors. NT reduced the coefficient of variation and paired-pulse ratio of AMPA EPSCs suggesting that NT facilitates presynaptic glutamate release. NT increased the release probability and the number of readily releasable vesicles with no effects on the rate of recovery from vesicle depletion. NT-mediated augmentation of glutamate release required the influx of Ca(2+) via L-type Ca(2+) channels and the functions of calmodulin and myosin light chain kinase. Our results provide a cellular and molecular mechanism to explain the roles of NT in the hippocampus.
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Affiliation(s)
- Haopeng Zhang
- Department of Basic Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA; Department of Anesthesiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi Province, PR China
| | - Hailong Dong
- Department of Anesthesiology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi Province, PR China
| | - Saobo Lei
- Department of Basic Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND 58203, USA.
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Elucidating the role of neurotensin in the pathophysiology and management of major mental disorders. Behav Sci (Basel) 2014; 4:125-153. [PMID: 25379273 PMCID: PMC4219245 DOI: 10.3390/bs4020125] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 05/15/2014] [Accepted: 05/21/2014] [Indexed: 12/30/2022] Open
Abstract
Neurotensin (NT) is a neuropeptide that is closely associated with, and is thought to modulate, dopaminergic and other neurotransmitter systems involved in the pathophysiology of various mental disorders. This review outlines data implicating NT in the pathophysiology and management of major mental disorders such as schizophrenia, drug addiction, and autism. The data suggest that NT receptor analogs have the potential to be used as novel therapeutic agents acting through modulation of neurotransmitter systems dys-regulated in these disorders.
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Zhang Y, Zhu S, Yi L, Liu Y, Cui H. Neurotensin receptor1 antagonist SR48692 reduces proliferation by inducing apoptosis and cell cycle arrest in melanoma cells. Mol Cell Biochem 2013; 389:1-8. [DOI: 10.1007/s11010-013-1920-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Accepted: 12/06/2013] [Indexed: 11/24/2022]
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Hypothalamic neurotensin projections promote reward by enhancing glutamate transmission in the VTA. J Neurosci 2013; 33:7618-26. [PMID: 23637156 DOI: 10.1523/jneurosci.2588-12.2013] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The lateral hypothalamus (LH) sends a dense glutamatergic and peptidergic projection to dopamine neurons in the ventral tegmental area (VTA), a cell group known to promote reinforcement and aspects of reward. The role of the LH to VTA projection in reward-seeking behavior can be informed by using optogenetic techniques to dissociate the actions of LH neurons from those of other descending forebrain inputs to the VTA. In the present study, we identify the effect of neurotensin (NT), one of the most abundant peptides in the LH to VTA projection, on excitatory synaptic transmission in the VTA and reward-seeking behavior. Mice displayed robust intracranial self-stimulation of LH to VTA fibers, an operant behavior mediated by NT 1 receptors (Nts1) and NMDA receptors. Whole-cell patch-clamp recordings of VTA dopamine neurons demonstrated that NT (10 nm) potentiated NMDA-mediated EPSCs via Nts1. Results suggest that NT release from the LH into the VTA activates Nts1, thereby potentiating NMDA-mediated EPSCs and promoting reward. The striking behavioral and electrophysiological effects of NT and glutamate highlight the LH to VTA pathway as an important component of reward.
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Dendritic sodium channels promote active decorrelation and reduce phase locking to parkinsonian input oscillations in model globus pallidus neurons. J Neurosci 2011; 31:10919-36. [PMID: 21795543 DOI: 10.1523/jneurosci.6062-10.2011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Correlated firing among populations of neurons is present throughout the brain and is often rhythmic in nature, observable as an oscillatory fluctuation in the local field potential. Although rhythmic population activity is believed to be critical for normal function in many brain areas, synchronized neural oscillations are associated with disease states in other cases. In the globus pallidus (GP in rodents, homolog of the primate GPe), pairs of neurons generally have uncorrelated firing in normal animals despite an anatomical organization suggesting that they should receive substantial common input. In contrast, correlated and rhythmic GP firing is observed in animal models of Parkinson's disease (PD). Based in part on these findings, it has been proposed that an important part of basal ganglia function is active decorrelation, whereby redundant information is compressed. Mechanisms that implement active decorrelation, and changes that cause it to fail in PD, are subjects of great interest. Rat GP neurons express fast, transient voltage-dependent sodium channels (NaF channels) in their dendrites, with the expression level being highest near asymmetric synapses. We recently showed that the dendritic NaF density strongly influences the responsiveness of model GP neurons to synchronous excitatory inputs. In the present study, we use rat GP neuron models to show that dendritic NaF channel expression is a potential cellular mechanism of active decorrelation. We further show that model neurons with lower dendritic NaF channel expression have a greater tendency to phase lock with oscillatory synaptic input patterns like those observed in PD.
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Ferraro L, Beggiato S, Tomasini MC, Fuxe K, Tanganelli S, Antonelli T. Neurotensin regulates cortical glutamate transmission by modulating N-methyl-D-aspartate receptor functional activity: an in vivo microdialysis study. J Neurosci Res 2011; 89:1618-26. [PMID: 21656844 DOI: 10.1002/jnr.22686] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 04/05/2011] [Accepted: 04/11/2011] [Indexed: 12/30/2022]
Abstract
The aim of the present in vivo microdialysis study was to investigate whether the tridecapeptide neurotensin (NT) influences the N-methyl-D-aspartate (NMDA) receptor-mediated increase of cortical glutamate transmission in freely moving rats. Intracortical perfusion with NT influenced local extracellular glutamate levels in a bell-shaped, concentration-dependent manner. One hundred and three hundred nanomolar NT concentrations increased glutamate levels (151% ± 7% and 124% ± 3% of basal values, respectively). Higher (1,000 nM) and lower (10 nM) NT concentrations did not alter extracellular glutamate levels. The NT receptor antagonist SR48692 (100 nM) prevented the NT (100 nM)-induced increase in glutamate levels. NMDA (100 and 500 μM) perfusion induced a concentration-dependent increase in extracellular glutamate levels, the lower 10 μM NMDA concentration being ineffective. When NT (10 nM, a concentration by itself ineffective) was added in combination with NMDA (100 μM) to the perfusion medium, a significant greater increase in extracellular glutamate levels (169% ± 7%) was observed with respect to the increase induced by NMDA (100 μM) alone (139% ± 4%). SR48692 (100 nM) counteracted the increase in glutamate levels induced by the treatment with NT (10 nM) plus NMDA (100 μM). The enhancement of cortical glutamate levels induced by NMDA (100 and 500 μM) was partially antagonized by the presence of SR48692, at a concentration (100 nM) that by itself was ineffective in modulating glutamate release. These findings indicate that NT plays a relevant role in the regulation of cortical glutamatergic transmission, especially by modulating the functional activity of cortical NMDA receptors. A possible role in glutamate-mediated neurotoxicity is suggested.
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Affiliation(s)
- Luca Ferraro
- Department of Clinical and Experimental Medicine, Pharmacology Section and LTTA Centre, Universityof Ferrara, Ferrara, Italy.
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Sardo P, Carletti F, Rizzo V, Lonobile G, Friscia S, Ferraro G. Nitric oxide-active compounds modulate the intensity of glutamate-evoked responses in the globus pallidus of the rat. Life Sci 2011; 88:1113-20. [DOI: 10.1016/j.lfs.2011.04.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 01/28/2011] [Accepted: 04/04/2011] [Indexed: 11/29/2022]
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Mitchell VA, Kawahara H, Vaughan CW. Neurotensin inhibition of GABAergic transmission via mGluR-induced endocannabinoid signalling in rat periaqueductal grey. J Physiol 2009; 587:2511-20. [PMID: 19359367 DOI: 10.1113/jphysiol.2008.167429] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Neurotensin modulates pain via its actions within descending analgesic pathways which include brain regions such as the midbrain periaqueductal grey (PAG). The aim of this study was to examine the cellular actions of neurotensin on PAG neurons. Whole cell patch clamp recordings were made from rat midbrain PAG slices in vitro to examine the postsynaptic effects of neurotensin and its effects on GABA(A) mediated inhibitory postsynaptic currents (IPSCs). Neurotensin (100-300 nM) produced an inward current in subpopulations of opioid sensitive and insensitive PAG neurons which did not reverse over membrane potentials between -50 and -130 mV. The neurotensin induced current was abolished by the NTS1 and NTS1/2 antagonists SR48692 (300 nM) and SR142948A (300 nM). Neurotensin also produced a reduction in the amplitude of evoked IPSCs, but had no effect on the rate and amplitude of TTX-resistant miniature IPSCs. The neurotensin induced inhibition of evoked IPSCs was reduced by the mGluR5 antagonist MPEP (5microM) and abolished by the cannabinoid CB(1) receptor antagonist AM251 (3 microM). These results suggest that neurotensin produces direct neuronal depolarisation via NTS1 receptors and inhibits GABAergic synaptic transmission within the PAG. The inhibition of synaptic transmission is mediated by neuronal excitation and action potential dependent release of glutamate, leading to mGluR5 mediated production of endocannabinoids which activate presynaptic CB(1) receptors. Thus, neurotensin has cellular actions within the PAG which are consistent with both algesic and analgesic activity, some of which are mediated via the endocannabinoid system.
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Affiliation(s)
- V A Mitchell
- Pain Management Research Institute, Northern Clinical School, University of Sydney at Royal North Shore Hospital, St Leonards, NSW, Australia
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Antonelli T, Tomasini MC, Fournier J, Mazza R, Tanganelli S, Pirondi S, Fuxe K, Ferraro L, Luca F. Neurotensin receptor involvement in the rise of extracellular glutamate levels and apoptotic nerve cell death in primary cortical cultures after oxygen and glucose deprivation. Cereb Cortex 2007; 18:1748-57. [PMID: 18063561 DOI: 10.1093/cercor/bhm217] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In view of the ability of neurotensin (NT) to increase glutamate release, the role of NT receptor mechanisms in oxygen-glucose deprivation (OGD)-induced neuronal degeneration in cortical cultures has been evaluated by measuring lactate dehydrogenase (LDH) levels, mitochondrial dehydrogenase activity with 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide levels, and microtubule-associated protein 2 (MAP2) immunoreactivity. Apoptotic nerve cell death was analyzed measuring chromatin condensation with Hoechst 33258, annexin V staining, and caspase-3 activity. Furthermore, the involvement of glutamate excitotoxicity in the neurodegeneration-enhancing actions of NT was analyzed by measurement of extracellular glutamate levels. NT enhanced the OGD-induced increase of LDH, endogenous extracellular glutamate levels, and apoptotic nerve cell death. In addition, the peptide enhanced the OGD-induced loss of mitochondrial functionality and increase of MAP2 aggregations. These effects were blocked by the neurotensin receptor 1 (NTR1) antagonist SR48692. Unexpectedly, the antagonist at 100 nM counteracted not only the NT effects but also some OGD-induced biochemical and morphological alterations. These results suggest that NTR1 receptors may participate in neurodegenerative events induced by OGD in cortical cultures, used as an in vitro model of cortical ischemia. The NTR1 receptor antagonists could provide a new tool to explore the clinical possibilities and thus to move from chemical compound to effective drug.
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Affiliation(s)
- Tiziana Antonelli
- Department of Clinical and Experimental Medicine, Pharmacology Section, University of Ferrara, 44100 Ferrara, Italy
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Ferraro L, Tomasini MC, Mazza R, Fuxe K, Fournier J, Tanganelli S, Antonelli T. Neurotensin receptors as modulators of glutamatergic transmission. ACTA ACUST UNITED AC 2007; 58:365-73. [PMID: 18096238 DOI: 10.1016/j.brainresrev.2007.11.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2007] [Revised: 11/02/2007] [Accepted: 11/05/2007] [Indexed: 12/22/2022]
Abstract
Functional studies have provided evidence supporting the concept that the tridecapeptide neurotensin (NT) acts in the central nervous system as a classical neurotransmitter and/or as an important modulator of neuronal signalling. The role of NT in the regulation of the striatal amino acidergic transmission, mainly by antagonising D2 receptor function, will be analysed. In addition, in different rat brain regions, including the basal ganglia, the contribution of NT receptors in modulating and reinforcing glutamate signalling will be shown including the involvement of interactions between NT and NMDA receptors. Since the enhancement of glutamate transmission and in particular the excessive activation of NMDA receptors, has been postulated to be an important factor in the induction of glutamate-mediated neuronal damage, the involvement of NT in the glutamate-induced neurodegenerative effects will be discussed. Moving from these observations and in order to further investigate this issue, results from preliminary behavioural, functional and biochemical experiments will be presented on the putative neuroprotective effect obtained by the blockade of NT receptor 1 (NTS1) via the systemic administration of the selective NTS1 antagonist SR48692 in an in vivo animal model of Parkinson's disease [unilateral nigral 6-hydroxydopamine (6-OHDA) induced lesion of the nigrostriatal pathway].
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Affiliation(s)
- Luca Ferraro
- Department of Clinical and Experimental Medicine, Section of Pharmacology, University of Ferrara, Via Fossato di Mortara 17-19, 44100 Ferrara, Italy
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Antonelli T, Fuxe K, Tomasini MC, Mazzoni E, Agnati LF, Tanganelli S, Ferraro L. Neurotensin receptor mechanisms and its modulation of glutamate transmission in the brain: relevance for neurodegenerative diseases and their treatment. Prog Neurobiol 2007; 83:92-109. [PMID: 17673354 DOI: 10.1016/j.pneurobio.2007.06.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2006] [Revised: 05/18/2007] [Accepted: 06/19/2007] [Indexed: 11/30/2022]
Abstract
The extracellular accumulation of glutamate and the excessive activation of glutamate receptors, in particular N-methyl-D-aspartate (NMDA) receptors, have been postulated to contribute to the neuronal cell death associated with chronic neurodegenerative disorders such as Parkinson's disease. Findings are reviewed indicating that the tridecaptide neurotensin (NT) via activation of NT receptor subtype 1 (NTS1) promotes and reinforces endogenous glutamate signalling in discrete brain regions. The increase of striatal, nigral and cortical glutamate outflow by NT and the enhancement of NMDA receptor function by a NTS1/NMDA interaction that involves the activation of protein kinase C may favour the depolarization of NTS1 containing neurons and the entry of calcium. These results strengthen the hypothesis that NT may be involved in the amplification of glutamate-induced neurotoxicity in mesencephalic dopamine and cortical neurons. The mechanisms involved may include also antagonistic NTS1/D2 interactions in the cortico-striatal glutamate terminals and in the nigral DA cell bodies and dendrites as well as in the nigro-striatal DA terminals. The possible increase in NT levels in the basal ganglia under pathological conditions leading to the NTS1 enhancement of glutamate signalling may contribute to the neurodegeneration of the nigro-striatal dopaminergic neurons found in Parkinson's disease, especially in view of the high density of NTS1 receptors in these neurons. The use of selective NTS1 antagonists together with conventional drug treatments could provide a novel therapeutic approach for treatment of Parkinson's disease.
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Affiliation(s)
- T Antonelli
- Department of Clinical and Experimental Medicine, Section of Pharmacology, University of Ferrara, 44100 Ferrara, Italy
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Ferraro L, Tomasini MC, Fuxe K, Agnati LF, Mazza R, Tanganelli S, Antonelli T. Mesolimbic dopamine and cortico-accumbens glutamate afferents as major targets for the regulation of the ventral striato-pallidal GABA pathways by neurotensin peptides. ACTA ACUST UNITED AC 2007; 55:144-54. [PMID: 17448541 DOI: 10.1016/j.brainresrev.2007.03.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Revised: 03/19/2007] [Accepted: 03/20/2007] [Indexed: 12/11/2022]
Abstract
The tridecapeptide neurotensin (NT) acts in the mammalian brain as a primary neurotransmitter or neuromodulator of classical neurotransmitters. Morphological and functional in vitro and in vivo studies have demonstrated the existence of close interactions between NT and dopamine both in limbic and in striatal brain regions. Additionally, biochemical and neurochemical evidence indicates that in these brain regions NT plays also a crucial role in the regulation of the aminoacidergic signalling. It is suggested that in the nucleus accumbens the regulation of prejunctional dopaminergic transmission induced by NT may be primarily due to indirect mechanism(s) involving mediation via the aminoacidergic neuronal systems with increased glutamate release followed by increased GABA release in the nucleus accumbens rather than a direct action of the peptide on accumbens dopaminergic terminals. The neurochemical profile of action of NT in the control of the pattern of dopamine, glutamate and GABA release in the nucleus accumbens differs to a substantial degree from that shown by the peptide in the dorsal striatum. The neuromodulatory NT mechanisms in the regulation of the ventral striato-pallidal GABA pathways are discussed and their relevance for schizophrenia is underlined.
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Affiliation(s)
- Luca Ferraro
- Department of Clinical and Experimental Medicine, Section of Pharmacology, University of Ferrara, Via Fossato di Mortara 17-19, 44100 Ferrara, Italy
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