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1.
Eur J Med Chem ; 186: 111881, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31780081

RESUMO

A scaffold hopping strategy converted the known 1-[(1-methyl-1H-imidazol-2-yl)methyl]-4-phenylpiperidine core (1 and 2) by cyclization to a fused [6 + 5+6] membered heterocyclic mGluR2 PAM scaffold. Pharmacophore guided structure-activity relationship (SAR) studies resulted in a series of potent and metabolically stable mGluR2 PAMs. A representative optimized compound (95) having the most balanced profile, demonstrated efficacy in the PCP-induced hyper-locomotion model in mice that revealed the new chemotype being a promising PAM lead targeting mGluR2 receptors and providing support for further translational studies.


Assuntos
Benzimidazóis/farmacologia , Descoberta de Drogas , Pirazinas/farmacologia , Receptores de Glutamato Metabotrópico/metabolismo , Regulação Alostérica/efeitos dos fármacos , Animais , Benzimidazóis/química , Células Cultivadas , Relação Dose-Resposta a Droga , Humanos , Camundongos , Microssomos Hepáticos/química , Microssomos Hepáticos/metabolismo , Estrutura Molecular , Pirazinas/química , Ratos , Ratos Wistar , Relação Estrutura-Atividade
2.
Curr Top Med Chem ; 19(29): 2687-2707, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31702505

RESUMO

BACKGROUND: Glutamate is the principal neurotransmitter in the human brain that exerts its effects through ionotropic glutamate receptors (iGluRs) and metabotropic glutamate receptors (mGluRs). The mGluRs are a class of C GPCRs that play a vital role in various neurobiological functions, mGluR1 and mGluR5 are the two receptors distributed throughout the brain involved in cognition, learning, memory, and other important neurological processes. Dysfunction of these receptors can cause neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, X-fragile syndrome, anxiety, depression, etc., hence these receptors are high profile targets for pharmaceutical industries. OBJECTIVE: The objective of our study is to find the novel dual negative allosteric modulators to regulate both mGluR1 and mGluR5. METHODS: In this study, shape screening protocol was used to find the dual negative allosteric modulators for both mGluR1 and mGluR5 followed by ADME prediction, induced-fit docking (IFD) and molecular dynamics simulations. Further, DFT analysis and MESP studies were carried out for the selected compounds. RESULTS: Around 247 compounds were obtained from the eMolecules database and clustered through the CANVAS module and filtered with ADME properties. Furthermore, IFD revealed that the top four compounds (16059796, 25004252, 4667236 and 11670690) having good protein-ligand interactions and binding free energies. The molecular electrostatic potential of the top compounds shows interactions in the amine group and the oxygen atom in the negative potential regions. Finally, molecular dynamics simulations were performed with all the selected as well as the reported compound 29 indicates that the screened hits have better stability of protein ligand complex. CONCLUSION: Hence, from the results, it is evident that top hits 16059796, 25004252, 4667236 and 11670690 could be a novel and potent dual negative allosteric modulators for mGluR1 and mGluR5.


Assuntos
Doenças Neurodegenerativas/terapia , Farmacocinética , Receptores de Glutamato Metabotrópico/metabolismo , Regulação Alostérica , Humanos , Ligantes , Simulação de Dinâmica Molecular , Doenças Neurodegenerativas/metabolismo
3.
Curr Top Med Chem ; 19(26): 2421-2446, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31660833

RESUMO

The amino terminal domain (ATD) of the metabotropic glutamate (mGlu) receptors contains the orthosteric glutamate recognition site, which is highly conserved across the eight mGlu receptor subtypes. In total, 29 X-ray crystal structures of the mGlu ATD proteins have been reported to date. These structures span across 3 subgroups and 6 subtypes, and include apo, agonist- and antagonist-bound structures. We will discuss the insights gained from the analysis of these structures with the focus on the interactions contributing to the observed group and subtype selectivity for select agonists. Furthermore, we will define the full expanded orthosteric ligand binding pocket (LBP) of the mGlu receptors, and discuss the macroscopic features of the mGlu ATD proteins.


Assuntos
Receptores de Glutamato Metabotrópico/metabolismo , Animais , Sítios de Ligação , Cristalografia por Raios X , Humanos , Conformação Proteica , Receptores de Glutamato Metabotrópico/química , Relação Estrutura-Atividade
4.
Int J Mol Sci ; 20(18)2019 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-31540330

RESUMO

Glutamate (Glu)-mediated excitotoxicity is a major cause of amyotrophic lateral sclerosis (ALS) and our previous work highlighted that abnormal Glu release may represent a leading mechanism for excessive synaptic Glu. We demonstrated that group I metabotropic Glu receptors (mGluR1, mGluR5) produced abnormal Glu release in SOD1G93A mouse spinal cord at a late disease stage (120 days). Here, we studied this phenomenon in pre-symptomatic (30 and 60 days) and early-symptomatic (90 days) SOD1G93A mice. The mGluR1/5 agonist (S)-3,5-Dihydroxyphenylglycine (3,5-DHPG) concentration dependently stimulated the release of [3H]d-Aspartate ([3H]d-Asp), which was comparable in 30- and 60-day-old wild type mice and SOD1G93A mice. At variance, [3H]d-Asp release was significantly augmented in 90-day-old SOD1G93A mice and both mGluR1 and mGluR5 were involved. The 3,5-DHPG-induced [3H]d-Asp release was exocytotic, being of vesicular origin and mediated by intra-terminal Ca2+ release. mGluR1 and mGluR5 expression was increased in Glu spinal cord axon terminals of 90-day-old SOD1G93A mice, but not in the whole axon terminal population. Interestingly, mGluR1 and mGluR5 were significantly augmented in total spinal cord tissue already at 60 days. Thus, function and expression of group I mGluRs are enhanced in the early-symptomatic SOD1G93A mouse spinal cord, possibly participating in excessive Glu transmission and supporting their implication in ALS. Please define all abbreviations the first time they appear in the abstract, the main text, and the first figure or table caption.


Assuntos
Esclerose Amiotrófica Lateral/genética , Receptor de Glutamato Metabotrópico 5/metabolismo , Receptores de Glutamato Metabotrópico/metabolismo , Superóxido Dismutase-1/genética , Esclerose Amiotrófica Lateral/metabolismo , Animais , Modelos Animais de Doenças , Progressão da Doença , Ácido Glutâmico/metabolismo , Glicina/administração & dosagem , Glicina/análogos & derivados , Glicina/farmacologia , Humanos , Camundongos , Mutação , Receptor de Glutamato Metabotrópico 5/genética , Receptores de Glutamato Metabotrópico/genética , Resorcinóis/administração & dosagem , Resorcinóis/farmacologia , Medula Espinal/metabolismo , Regulação para Cima
5.
BMC Cancer ; 19(1): 891, 2019 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-31492116

RESUMO

BACKGROUND: Glutamate metabotropic receptors (GRM) play a variety of roles in neuronal cells. However, their clinical significance and biological functions in breast cancer remain unknown. METHODS: RNA sequencing data of breast cancer was obtained from the TCGA dataset (v2) and mined for the expression profiles of GRM family according to cancer subtypes. mRNA expression of GRM family in breast cancer tissues and para-cancerous tissue samples as well as breast cancer cell lines were measured by qPCR. The effects of over- and under-expression of GRM4 on cell capabilities to survive, migrate and invade were determined by colony formation, transwell migration and invasion assays. To explore the upstream regulation pattern of GRM4, miRNAs that target GRM4 were predicted and validated by dual luciferase reporter assay. In addition, the mRNA and protein expression of GRM4 regulated by these miRNAs were further measured by qPCR and western blot assay. RESULTS: GRM4 was the only GRM member that expressed in breast cancer tissues. Ectopic expression of GRM4 was correlated with better prognosis of breast cancer patients. Overexpression of GRM4 could significantly inhibit cell proliferation, migration and invasion capacity in MDA-MB-231, while knockdown of GRM4 could promote these processes. miR-328-3p and miR-370-3p were predicted to regulate the expression of GRM4 and dual luciferase reporter assay demonstrated that miR-328-3p and miR-370-3p directly bound to the 3' UTR of GRM4 and mutations on the binding regions on GRM4 significantly decreased the luciferase activity. qPCR demonstrated that expression of miR-328-3p and miR-370-3p was significantly decreased in breast cancer tissues and cells compared with that in control samples. However, there were no correlations between the expression of miR-328-3p and GRM4, as well as the expression of miR-370-3p and GRM4. Moreover, overexpression of miR-328-3p and miR-370-3p counteracted the inhibitory effect of GRM4-induced cell proliferation, migration and invasion. CONCLUSIONS: Our results suggest that GRM4 might be a tumor suppressor gene in breast cancer under the direct regulation of miR-328-3p and miR-370-3p.


Assuntos
Neoplasias da Mama/patologia , Regulação Neoplásica da Expressão Gênica/genética , MicroRNAs/metabolismo , Receptores de Glutamato Metabotrópico/genética , Receptores de Glutamato Metabotrópico/metabolismo , Regiões 3' não Traduzidas , Sítios de Ligação , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Feminino , Humanos , MicroRNAs/genética , Prognóstico
6.
Curr Top Med Chem ; 19(19): 1768-1781, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31393248

RESUMO

Metabotropic glutamate receptors (mGluR) are members of the class C G-Protein Coupled Receptors (GPCR-s) and have eight subtypes. These receptors are responsible for a variety of functions in the central and peripheral nervous systems and their modulation has therapeutic utility in neurological and psychiatric disorders. It was previously established that selective orthosteric modulation of these receptors is challenging, and this stimulated the search for allosteric modulators. Fragment-Based Drug Discovery (FBDD) is a viable approach to find ligands binding at allosteric sites owing to their limited size and interactions. However, it was also observed that the structure-activity relationship of allosteric modulators is often sharp and inconsistent. This can be attributed to the characteristics of the allosteric binding site of mGluRs that is a water channel where ligand binding is accompanied with induced fit and interference with the water network, both playing a role in receptor activation. In this review, we summarize fragment-based drug discovery programs on mGluR allosteric modulators and their contribution identifying of new mGluR ligands with better activity and selectivity.


Assuntos
Fármacos Neuroprotetores/farmacologia , Receptores de Glutamato Metabotrópico/antagonistas & inibidores , Regulação Alostérica/efeitos dos fármacos , Animais , Descoberta de Drogas , Humanos , Ligantes , Transtornos Mentais/tratamento farmacológico , Transtornos Mentais/metabolismo , Doenças do Sistema Nervoso/tratamento farmacológico , Doenças do Sistema Nervoso/metabolismo , Fármacos Neuroprotetores/química , Receptores de Glutamato Metabotrópico/metabolismo
7.
Elife ; 82019 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-31373553

RESUMO

The metabotropic glutamate receptor 7 (mGlu7) is a class C G protein-coupled receptor that modulates excitatory neurotransmitter release at the presynaptic active zone. Although post-translational modification of cellular proteins with ubiquitin is a key molecular mechanism governing protein degradation and function, mGlu7 ubiquitination and its functional consequences have not been elucidated yet. Here, we report that Nedd4 ubiquitin E3 ligase and ß-arrestins regulate ubiquitination of mGlu7 in heterologous cells and rat neurons. Upon agonist stimulation, ß-arrestins recruit Nedd4 to mGlu7 and facilitate Nedd4-mediated ubiquitination of mGlu7. Nedd4 and ß-arrestins regulate constitutive and agonist-induced endocytosis of mGlu7 and are required for mGlu7-dependent MAPK signaling in neurons. In addition, Nedd4-mediated ubiquitination results in the degradation of mGlu7 by both the ubiquitin-proteasome system and the lysosomal degradation pathway. These findings provide a model in which Nedd4 and ß-arrestin act together as a complex to regulate mGlu7 surface expression and function at presynaptic terminals.


Assuntos
Ubiquitina-Proteína Ligases Nedd4/metabolismo , Receptores de Glutamato Metabotrópico/metabolismo , Ubiquitinação , beta-Arrestinas/metabolismo , Animais , Células Cultivadas , Regulação da Expressão Gênica , Humanos , Transporte Proteico , Ratos
8.
Nat Struct Mol Biol ; 26(7): 535-544, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31270468

RESUMO

Metabotropic receptors are responsible for so-called 'slow synaptic transmission' and mediate the effects of hundreds of peptide and non-peptide neurotransmitters and neuromodulators. Over the past decade or so, a revolution in membrane-protein structural determination has clarified the molecular determinants responsible for the actions of these receptors. This Review focuses on the G protein-coupled receptors (GPCRs) that are targets of neuropsychiatric drugs and shows how insights into the structure and function of these important synaptic proteins are accelerating understanding of their actions. Notably, elucidating the structure and function of GPCRs should enhance the structure-guided discovery of novel chemical tools with which to manipulate and understand these synaptic proteins.


Assuntos
Descoberta de Drogas , Receptores Acoplados a Proteínas-G/metabolismo , Transmissão Sináptica/efeitos dos fármacos , Animais , Fármacos do Sistema Nervoso Central/química , Fármacos do Sistema Nervoso Central/farmacologia , Desenho de Drogas , Descoberta de Drogas/métodos , Humanos , Transtornos Mentais/tratamento farmacológico , Modelos Moleculares , Terapia de Alvo Molecular , Neurotransmissores/metabolismo , Receptores Acoplados a Proteínas-G/agonistas , Receptores Acoplados a Proteínas-G/antagonistas & inibidores , Receptores Acoplados a Proteínas-G/química , Receptores de Glutamato Metabotrópico/agonistas , Receptores de Glutamato Metabotrópico/antagonistas & inibidores , Receptores de Glutamato Metabotrópico/química , Receptores de Glutamato Metabotrópico/metabolismo
9.
Cell Mol Neurobiol ; 39(8): 1165-1175, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31270711

RESUMO

Bone cancer pain (BCP), which is induced by primary or metastatic bone cancer, remains a clinically challenging problem due to the poor understanding of its mechanisms. Sirtuin 1 (SIRT1) plays an important role in various pain models. Intrathecal administration of SRT1720, a SIRT1 activator, attenuates BCP in a rat model. However, the expression and activity of SIRT1 during the development and maintenance of BCP remain unknown. Furthermore, the underlying mechanism of SIRT1 in BCP remains ambiguous. In this study, we detected the time course of SIRT1 expression and activity in the spinal cord of mice with BCP and examined whether SRT1720 alleviated BCP by inhibiting metabotropic glutamatergic receptor (mGluR) 1/5 expression. In addition, we downregulated spinal SIRT1 expression in normal mice through an intrathecal injection of AAV-SIRT1-shRNA and then assessed pain behavior and mGluR1/5 expression. Mice with BCP developed significant mechanical allodynia and spontaneous flinching, accompanied by decreased levels of the SIRT1 protein, mRNA, and activity in the spinal cord. The SRT1720 treatment produced an analgesic effect on tumor-bearing mice and decreased the spinal levels of the mGluR1/5 protein and mRNA. In contrast, the AAV-SIRT1-shRNA treatment induced pain behavior in normal mice and increased the spinal levels of the mGluR1/5 protein and mRNA. The results suggested a critical role for SIRT1 in the development and maintenance of BCP and further indicated that activation of SIRT1 in the spinal cord by SRT1720 functionally reverses BCP in mice by inhibiting mGluR1/5.


Assuntos
Neoplasias Ósseas/complicações , Dor do Câncer/etiologia , Dor do Câncer/metabolismo , Receptor de Glutamato Metabotrópico 5/metabolismo , Receptores de Glutamato Metabotrópico/metabolismo , Sirtuína 1/metabolismo , Animais , Comportamento Animal , Modelos Animais de Doenças , Regulação para Baixo/efeitos dos fármacos , Compostos Heterocíclicos de 4 ou mais Anéis/administração & dosagem , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Injeções Espinhais , Masculino , Camundongos , Medula Espinal/metabolismo , Medula Espinal/patologia , Regulação para Cima/efeitos dos fármacos
10.
Biomolecules ; 9(6)2019 06 17.
Artigo em Inglês | MEDLINE | ID: mdl-31213006

RESUMO

Pharmacological mechanisms of gold-standard antipsychotics against treatment-refractory schizophrenia, such as clozapine (CLZ), remain unclear. We aimed to explore the mechanisms of CLZ by investigating the effects of MK801 and CLZ on tripartite synaptic transmission in the thalamocortical glutamatergic pathway using multi-probe microdialysis and primary cultured astrocytes. l-glutamate release in the medial prefrontal cortex (mPFC) was unaffected by local MK801 administration into mPFC but was enhanced in the mediodorsal thalamic nucleus (MDTN) and reticular thalamic nucleus (RTN) via GABAergic disinhibition in the RTN-MDTN pathway. The local administration of therapeutically relevant concentrations of CLZ into mPFC and MDTN increased and did not affect mPFC l-glutamate release. The local administration of the therapeutically relevant concentration of CLZ into mPFC reduced MK801-induced mPFC l-glutamate release via presynaptic group III metabotropic glutamate receptor (III-mGluR) activation. However, toxic concentrations of CLZ activated l-glutamate release associated with hemichannels. This study demonstrated that RTN is a candidate generator region in which impaired N-methyl-d-aspartate (NMDA)/glutamate receptors likely produce thalamocortical hyperglutamatergic transmission. Additionally, we identified several mechanisms of CLZ relating to its superiority in treatment-resistant schizophrenia and its severe adverse effects: (1) the prevention of thalamocortical hyperglutamatergic transmission via activation of mPFC presynaptic III-mGluR and (2) activation of astroglial l-glutamate release associated with hemichannels. These actions may contribute to the unique clinical profile of CLZ.


Assuntos
Clozapina/farmacologia , Ácido Glutâmico/metabolismo , Núcleo Mediodorsal do Tálamo/efeitos dos fármacos , Córtex Pré-Frontal/efeitos dos fármacos , Receptores de Glutamato Metabotrópico/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Transmissão Sináptica/efeitos dos fármacos , Animais , Maleato de Dizocilpina/farmacologia , Relação Dose-Resposta a Droga , Espaço Extracelular/efeitos dos fármacos , Espaço Extracelular/metabolismo , Núcleo Mediodorsal do Tálamo/citologia , Núcleo Mediodorsal do Tálamo/metabolismo , Córtex Pré-Frontal/metabolismo , Ratos , Ácido gama-Aminobutírico/metabolismo
11.
Expert Opin Ther Pat ; 29(7): 497-507, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31242055

RESUMO

INTRODUCTION: Positive allosteric modulation of mGlu2 has attracted much interest as an alternative approach to classical orthosteric receptor activation. Two mGlu2 PAMS have advanced into the clinic. The results obtained in schizophrenia and MDD phase 2 clinical trials have tempered the high expectations put on selective mGlu2 receptor activation for treating these conditions; nevertheless, the search for novel therapeutic indications and novel chemotypes continues to be an active field of research. AREAS COVERED: 2013-2018 patent literature on mGlu2 receptor PAMs. EXPERT OPINION: After a decade of intensive research, the mGlu2 PAM field has seen a deceleration in the last five years. Negative phase 2 schizophrenia clinical trials with JNJ-40411813 and AZD8529 seem to have tempered the high expectations of the scientific community on the utility of mGlu2 PAMs for the treatment of schizophrenia. Nevertheless, novel therapeutic indications continue to be explored and AZD8529 is currently in a phase 2 study for smoking cessation. The advances in medicinal chemistry and in pharmacology, with novel indications such as epilepsy, have set the stage in the field of mGlu2 receptor PAMs. Ongoing preclinical and clinical studies will contribute to define their optimal therapeutic indication and potential to become novel therapeutic agents.


Assuntos
Indóis/uso terapêutico , Oxidiazóis/uso terapêutico , Piperidinas/uso terapêutico , Piridonas/uso terapêutico , Receptores de Glutamato Metabotrópico/efeitos dos fármacos , Regulação Alostérica/efeitos dos fármacos , Animais , Transtorno Depressivo Maior/tratamento farmacológico , Transtorno Depressivo Maior/fisiopatologia , Humanos , Indóis/farmacologia , Oxidiazóis/farmacologia , Patentes como Assunto , Piperidinas/farmacologia , Piridonas/farmacologia , Receptores de Glutamato Metabotrópico/metabolismo , Esquizofrenia/tratamento farmacológico , Esquizofrenia/fisiopatologia
12.
Life Sci ; 231: 116567, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31202839

RESUMO

AIMS: Metabotropic glutamate receptor 5 (mGluR5), a member of group I mGluR, exerts its effect via elevation of intracellular Ca2+ level. We here characterized Ca2+ signals in the tsA201 cells transfected with mGluR5 and investigated the role of passages for mGluR5-induced Ca2+ signals in synaptic plasticity. MAIN METHODS: Using a genetically encoded Ca2+ indicator, GCamp2, Ca2+ signals were reliably induced by bath application of (S)-3,5-dihydroxyphenylglycine, the group I mGluR agonist, in the tsA201 cells transfected with mGluR5. Using whole-cell recordings in the substantia gelatinosa (SG) neurons of the spinal trigeminal subnucleus caudalis (Vc), excitatory postsynaptic currents were recorded by stimulating the trigeminal tract. KEY FINDINGS: Ca2+ signals were mediated by "classical" or "canonical" transient receptor potential (TRPC) channels, particularly TRPC1/3/4/6, but not TRPC5, naturally existing in the tsA201 cells. Interestingly, the induction of Ca2+ signals was independent of the phospholipase C signaling pathway; instead, it critically involves the cyclic adenosine diphosphate ribose/ryanodine receptor-dependent signaling pathway and only partially protein kinase C. On the other hand, both TRPC3 and TRPC4 mediated mGluR1/5-induced long-lasting potentiation of excitatory synaptic transmission from the trigeminal primary afferents to the SG neurons of the Vc. SIGNIFICANCE: This study demonstrates that endogenous TRPC channels contribute to mGluR5-induced Ca2+ signals in tsA201 cells and synaptic plasticity at excitatory synapses.


Assuntos
Sinalização do Cálcio/fisiologia , Plasticidade Neuronal/efeitos dos fármacos , Receptor de Glutamato Metabotrópico 5/metabolismo , Canais de Cátion TRPC/metabolismo , Animais , Cálcio/metabolismo , Canais de Cálcio/metabolismo , Antagonistas de Aminoácidos Excitatórios/farmacologia , Potenciais Pós-Sinápticos Excitadores , Feminino , Potenciação de Longa Duração/efeitos dos fármacos , Masculino , Plasticidade Neuronal/fisiologia , Neurônios/metabolismo , Técnicas de Patch-Clamp , Ratos , Ratos Sprague-Dawley , Receptores de Glutamato Metabotrópico/metabolismo , Sinapses/metabolismo , Transmissão Sináptica , Nervo Trigêmeo/metabolismo , Núcleo Espinal do Trigêmeo/metabolismo
13.
Neuropharmacology ; 155: 76-88, 2019 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-31128122

RESUMO

Neurotensin (NT) is a 13-amino acid peptide acting as a neuromodulator in the CNS. NT immunoreactive cell bodies, synaptic terminals and receptors (NTS) are intimately associated with the dopaminergic system. In fact, NT exerts a stimulatory action on the dopaminergic (DAergic) neurons of substantia nigra pars compacta (SNpc) and ventral tegmental area by activating a mixed cation conductance, reducing D2-autoinhibition and modulating NMDA and AMPA transmission. In the present work, we describe an inhibitory effect of NT on metabotropic glutamate receptor I (mGluR I) actions in rat SNpc DAergic neurons. NTS and mGluR I share the same Gαq/11-PLC-IP3-Ca2+ intracellular pathway which causes either activation of unspecific cationic conductance or intracellular Ca2+ accumulation. We find that NT inhibits both inward current and the associated intracellular calcium elevation, elicited by the selective mGluR I agonist S-DHPG, in a concentration-dependent manner. This effect is mediated by type 1/2 NT receptors (NTS1/2), as revealed by pharmacological analysis. Activation of other metabotropic receptors, such as muscarinic and GABAB, does not inhibit mGluR I inward currents. PKC, MEK 1-2, calcineurin, clathrin-dependent endocytosis and intracellular Ca2+ elevation are not involved in the NT-mediated modulation of mGluR I responses. Interestingly, inhibition of G-protein coupled receptor kinases (GRKs) 2/3 exacerbates the NT-induced mGluR I inhibition while sustaining the NT-induced inward current during repeated agonist stimulation. These data suggest that GRKs are key molecules regulating either the NT excitation or the cross-talk between NTS1/2 and mGluR I in DAergic neurons of rat midbrain by tuning the degree of NTS1/2 desensitization.


Assuntos
Neurônios Dopaminérgicos/metabolismo , Quinases de Receptores Acoplados a Proteína G/metabolismo , Neurotensina/farmacologia , Receptores de Glutamato Metabotrópico/metabolismo , Receptores de Neurotensina/metabolismo , Substância Negra/metabolismo , Animais , Neurônios Dopaminérgicos/efeitos dos fármacos , Feminino , Masculino , Técnicas de Cultura de Órgãos , Ratos , Ratos Wistar , Receptores de Glutamato Metabotrópico/antagonistas & inibidores , Substância Negra/efeitos dos fármacos
14.
Neuropharmacology ; 155: 121-130, 2019 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-31129151

RESUMO

The ability to either erase or update the memories of a previously learned spatial task is an essential process that is required to modify behaviour in a changing environment. Current evidence suggests that the neural representation of such cognitive flexibility involves the balancing of synaptic potentiation (acquisition of memories) with synaptic depression (modulation and updating previously acquired memories). Here we demonstrate that the p38 MAPK/MAPK-activated protein kinase 2 (MK2) cascade is required to maintain the precise tuning of long-term potentiation and long-term depression at CA1 synapses of the hippocampus which is correlated with efficient reversal learning. Using the MK2 knockout (KO) mouse, we show that mGluR-LTD, but not NMDAR-LTD, is markedly impaired in mice aged between 4 and 5 weeks (juvenile) to 7 months (mature adult). Although the amplitude of LTP was the same as in wildtype mice, priming of LTP by the activation of group I metabotropic receptors was impaired in MK2 KO mice. Consistent with unaltered LTP amplitude and compromised mGluR-LTD, MK2 KO mice had intact spatial learning when performing the Barnes maze task, but showed specific deficits in selecting the most efficient combination of search strategies to perform the task reversal. Findings from this study suggest that the mGluR-p38-MK2 cascade is important for cognitive flexibility by regulating LTD amplitude and the priming of LTP.


Assuntos
Hipocampo/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/deficiência , Plasticidade Neuronal/fisiologia , Proteínas Serina-Treonina Quinases/deficiência , Receptores de Glutamato Metabotrópico/metabolismo , Reversão de Aprendizagem/fisiologia , Animais , Potenciais Pós-Sinápticos Excitadores/fisiologia , Peptídeos e Proteínas de Sinalização Intracelular/genética , Depressão Sináptica de Longo Prazo/fisiologia , Sistema de Sinalização das MAP Quinases/fisiologia , Camundongos , Camundongos Knockout , Técnicas de Cultura de Órgãos , Proteínas Serina-Treonina Quinases/genética
15.
Pharmacol Res Perspect ; 7(3): e00471, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31065376

RESUMO

Metabotropic glutamate receptors (mGluRs) are class C G protein coupled receptors with widespread expression in the central nervous system. There are eight mGluRs in the mammalian genome. Research on mGluRs relies on the availability of selective compounds. While many selective allosteric compounds have been described, selectivity of orthosteric agonists and antagonists has been more difficult due to the similarity of the glutamate binding pocket across the mGluR family. LY341495 has been used for decades as a potent and selective group II mGluR antagonist. The selectivity of LY341495 was investigated here between mGluR2, a group II mGluR, and mGluR4, a group III receptor, heterologously expressed in adult rat sympathetic neurons from the superior cervical ganglion (SCG), which provides a null-mGluR background upon which mGluRs were examined in isolation. The compound does in fact selectively inhibit mGluR2 over mGluR4, but in such a way that it makes signaling of the two receptors more difficult to distinguish. The glutamate potency of mGluR2 is about 10-fold higher than mGluR4. 50 nmol L-1 LY341495 did not alter mGluR4 signaling but shifted the mGluR2 glutamate dose-response about 10-fold, such that it overlapped more closely with that of mGluR4. Increasing the LY341494 dose to 500 nmol L-1 further shifted the glutamate dose-response of mGluR2 by another ~10-fold, but also shifted that of mGluR4 similarly. Thus, while glutamate is a moderately selective agonist of mGluR2 over mGluR4 when applied alone, in the presence of increasing concentrations of LY341495, this selectivity of glutamate is lost.


Assuntos
Aminoácidos/farmacologia , Receptores de Glutamato Metabotrópico/metabolismo , Gânglio Cervical Superior/metabolismo , Xantenos/farmacologia , Animais , Relação Dose-Resposta a Droga , Regulação para Baixo , Gânglios Simpáticos/citologia , Gânglios Simpáticos/efeitos dos fármacos , Gânglios Simpáticos/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Masculino , Ratos , Receptores de Glutamato Metabotrópico/genética , Transdução de Sinais/efeitos dos fármacos , Gânglio Cervical Superior/citologia , Gânglio Cervical Superior/efeitos dos fármacos
16.
Brain Dev ; 41(7): 567-576, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30954358

RESUMO

BACKGROUNDS: Metabotropic glutamate receptors, besides ionotropic receptors, mediate the complicated effect of glutamate on neurogenesis. Previous studies showed that metabotropic glutamate receptor 4 (mGluR4) regulated the proliferation and differentiation of neural stem/progenitor cells in vitro. However, little is known about the expression pattern of mGluR4 on prenatal central nervous system in vivo, especially the human being. METHODS: The normal brain tissues of human fetus were collected and divided into 4 groups according to the gestational age: 9-11 W, 14-16 W, 22-24 W and 32-36 W. Then the expression of mGluR4 was evaluated at mRNA and protein levels by means of PCR or immunohistochemistry method, respectively. The type of cell expressing mGluR4 was further investigated using double-labeling immunofluorescence. RESULTS: RT-PCR showed that the mRNA of mGluR4 could be detected in frontal lobe from 9 W to 32 W and real-time PCR quantificationally demonstrated the mRNA increased with development. Similarly, immnoreactivity was found in all layers of frontal lobe, VZ/SVZ. The intensity scores analysis showed that the staining became stronger and the range extended gradually with development. The double-labeling immunofluorescence showed that mGluR4 was present in neural stem/progenitor cells (nestin-positive cells after 9 W), young neurons (DCX-positive cells after 9 W), mature neurons (NeuN-positive cells in cortex after 32 W), as well as typical astrocytes (GFAP-positive cells in medulla after 32 W). CONCLUSION: These results supply an important evidence that mGluR4 is expressed in prenatal human cerebrum, and main kinds of cells related to neurogenesis are involved in its expression.


Assuntos
Encéfalo/embriologia , Lobo Frontal/embriologia , Receptores de Glutamato Metabotrópico/metabolismo , Encéfalo/metabolismo , Diferenciação Celular/fisiologia , Sistema Nervoso Central/citologia , Sistema Nervoso Central/embriologia , Sistema Nervoso Central/metabolismo , Córtex Cerebral/citologia , Córtex Cerebral/embriologia , Córtex Cerebral/metabolismo , Feminino , Desenvolvimento Fetal/genética , Lobo Frontal/citologia , Lobo Frontal/metabolismo , Ácido Glutâmico/metabolismo , Humanos , Imuno-Histoquímica , Masculino , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Neurogênese/fisiologia , Neurônios/metabolismo , Gravidez , Receptores de Glutamato Metabotrópico/genética
17.
Int J Mol Sci ; 20(7)2019 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-30970677

RESUMO

This study investigated whether metabotropic glutamate receptor (mGluR) 5 and 8 are involved in the effect of ultramicronizedpalmitoylethanolamide (um-PEA) on the cognitive behavior and long term potentiation (LTP) at entorhinal cortex (LEC)-dentate gyrus (DG) pathway in mice rendered neuropathic by the spare nerve injury (SNI). SNI reduced discriminative memory and LTP. Um-PEA treatment started after the development of neuropathic pain had no effects in sham mice, whereas it restored cognitive behavior and LTP in SNI mice. 2-Methyl-6-(phenylethynyl) pyridine (MPEP), a selective mGluR5 antagonist, improved cognition in SNI mice and produced a chemical long term depression of the field excitatory postsynaptic potentials (fEPSPs) in sham and SNI mice. After theta burst stimulation (TBS) MPEP restored LTP in SNI mice. In combination with PEA, MPEP antagonized the PEA effect on discriminative memory and decreased LTP in SNI mice. The (RS)-4-(1-amino-1-carboxyethyl)phthalic acid (MDCPG), a selective mGluR8 antagonist, did not affect discriminative memory, but it induced a chemical LTP and prevented the enhancement of fEPSPs after TBS in SNI mice which were treated or not treated with PEA. The effect of PEA on LTP and cognitive behavior was modulated by mGluR5 and mGluR8. In particular in the SNI conditions, the mGluR5 blockade facilitated memory and LTP, but prevented the beneficial effects of PEA on discriminative memory while the mGluR8 blockade, which was ineffective in itself, prevented the favorable action of the PEA on LTP. Thus, although their opposite roles (excitatory/inhibitory of the two receptor subtypes on the glutamatergic system), they appeared to be required for the neuroprotective effect of PEA in conditions of neuropathic pain.


Assuntos
Etanolaminas/administração & dosagem , Neuralgia/tratamento farmacológico , Ácidos Palmíticos/administração & dosagem , Traumatismos dos Nervos Periféricos/tratamento farmacológico , Receptor de Glutamato Metabotrópico 5/metabolismo , Receptores de Glutamato Metabotrópico/metabolismo , Animais , Giro Denteado/efeitos dos fármacos , Giro Denteado/metabolismo , Modelos Animais de Doenças , Etanolaminas/farmacologia , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Humanos , Potenciação de Longa Duração/efeitos dos fármacos , Masculino , Memória/efeitos dos fármacos , Camundongos , Neuralgia/etiologia , Neuralgia/metabolismo , Córtex Olfatório/efeitos dos fármacos , Córtex Olfatório/metabolismo , Ácidos Palmíticos/farmacologia , Traumatismos dos Nervos Periféricos/complicações , Traumatismos dos Nervos Periféricos/metabolismo , Piridinas/administração & dosagem , Piridinas/farmacologia
18.
Nat Commun ; 10(1): 1882, 2019 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-31015396

RESUMO

Glutamate is a major excitatory neurotransmitter, and impaired glutamate clearance following synaptic release promotes spillover, inducing extra-synaptic signaling. The effects of glutamate spillover on animal behavior and its neural correlates are poorly understood. We developed a glutamate spillover model in Caenorhabditis elegans by inactivating the conserved glial glutamate transporter GLT-1. GLT-1 loss drives aberrant repetitive locomotory reversal behavior through uncontrolled oscillatory release of glutamate onto AVA, a major interneuron governing reversals. Repetitive glutamate release and reversal behavior require the glutamate receptor MGL-2/mGluR5, expressed in RIM and other interneurons presynaptic to AVA. mgl-2 loss blocks oscillations and repetitive behavior; while RIM activation is sufficient to induce repetitive reversals in glt-1 mutants. Repetitive AVA firing and reversals require EGL-30/Gαq, an mGluR5 effector. Our studies reveal that cyclic autocrine presynaptic activation drives repetitive reversals following glutamate spillover. That mammalian GLT1 and mGluR5 are implicated in pathological motor repetition suggests a common mechanism controlling repetitive behaviors.


Assuntos
Comportamento Animal/fisiologia , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/fisiologia , Ácido Glutâmico/metabolismo , Terminações Pré-Sinápticas/fisiologia , Receptores de Glutamato Metabotrópico/metabolismo , Animais , Animais Geneticamente Modificados , Conjuntos de Dados como Assunto , Transportador 2 de Aminoácido Excitatório/metabolismo , Perfilação da Expressão Gênica , Interneurônios/metabolismo , Locomoção/fisiologia , Modelos Animais , Receptor de Glutamato Metabotrópico 5 , Receptores de Glutamato Metabotrópico/genética
19.
Psychiatry Res Neuroimaging ; 287: 63-69, 2019 05 30.
Artigo em Inglês | MEDLINE | ID: mdl-30991250

RESUMO

The function of group I metabotropic glutamate receptors mGluR1 and mGluR5 is involved in the hyperglutamatergic state caused by chronic alcohol. Preclinical studies suggest that group I mGluR modulation could serve as a novel treatment of alcoholism. Considering the wide role of glutamatergic neurochemistry in addiction, group I mGluR binding was studied in brain areas involved in decision-making, learning and memory. Post-mortem whole hemisphere autoradiography was used to study the binding density of [³H]quisqualic acid, a potent group I mGluR agonist, in 9 Cloninger type 1 alcoholics, 8 Cloninger type 2 alcoholics and 10 controls. Binding was studied in the dorsal striatum, hippocampus and cortex. Alcoholics displayed a trend towards increased [³H]quisqualic acid binding in all brain areas. The most robust findings were in the putamen (p = 0.006) and anterior insula (p = 0.005), where both alcoholic subtypes displayed increased binding compared to the controls. These findings suggest altered group I mGluR function in alcoholic subjects in the dorsal striatum, which is involved in habitual learning, and in the anterior insula, which has a pivotal role in the perception of bodily sensations. Increased [³H]quisqualic acid binding might suggest a beneficial impact of mGluR1/5 modulators in the treatment of alcoholism.


Assuntos
Alcoolismo/metabolismo , Encéfalo/metabolismo , Ácido Quisquálico/metabolismo , Receptor de Glutamato Metabotrópico 5/metabolismo , Receptores de Glutamato Metabotrópico/metabolismo , Adulto , Alcoólicos , Autorradiografia , Feminino , Hipocampo/fisiopatologia , Humanos , Masculino
20.
Int J Mol Sci ; 20(7)2019 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-30978987

RESUMO

Glioblastoma multiforme (GBM) is the most aggressive malignant tumor of the central nervous system, with poor survival in both treated and untreated patients. Recent studies began to explain the molecular pathway, comprising the dynamic structural and mechanical changes involved in GBM. In this context, some studies showed that the human glioblastoma cells release high levels of glutamate, which regulates the proliferation and survival of neuronal progenitor cells. Considering that cancer cells possess properties in common with neural progenitor cells, it is likely that the functions of glutamate receptors may affect the growth of cancer cells and, therefore, open the road to new and more targeted therapies.


Assuntos
Neoplasias do Sistema Nervoso Central/patologia , Glioblastoma/patologia , Invasividade Neoplásica/patologia , Receptores de Glutamato/metabolismo , Animais , Fenômenos Biomecânicos , Movimento Celular , Neoplasias do Sistema Nervoso Central/metabolismo , Glioblastoma/metabolismo , Ácido Glutâmico/metabolismo , Humanos , Canais Iônicos/metabolismo , Receptores de Glutamato Metabotrópico/metabolismo , Transdução de Sinais
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