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1.
Ann Agric Environ Med ; 27(2): 260-268, 2020 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-32588603

RESUMO

INTRODUCTION: Marijuana is one of the most widely used psychoactive substance. There is evidence of genetic predisposition for addiction. OBJECTIVE: The aim of the study is to evaluate personality traits measured by the NEO Five-Factor Inventory and State-Trait Anxiety Inventory, combined with analysis of Tag1B rs1079597 and Tag1D rs1800498 located in the DRD2 gene. MATERIAL AND METHODS: The study group consisted of 214 rural cannabinoid users and 301 controls. The same psychometric test and real-time PCR genotyping were performed in both studied groups. RESULTS: The values of Anxiety state, Anxiety trait, NEO FFI: Neuroticism and Openness in the rural cannabis using group were significantly higher than in the control group. On the other hand, lower values were observed among rural people using cannabis compared to the control group for NEO FFI: Extraversion, Agreeability and Conscientiousness. In the Anxiety trait subscale, a 2% association with the polymorphism DRD2 Tag1B rs1079597 was detected in subjects using cannabis. However, for the DRD2 Tag1D rs1800498, there was no effect on the differences in personality traits between rural cannabis users and the control group. CONCLUSIONS: The study shows differences in personality traits between the cannabis using group and controls. Interaction between genetic factors and personality traits was also detected. The association showing the combination of psychological characteristics and genetic variants can bring us closer to the overall picture of the issue of marijuana addiction.


Assuntos
Cannabis , Usuários de Drogas/psicologia , Personalidade/genética , Polimorfismo Genético , Receptores de Dopamina D2/genética , População Rural/estatística & dados numéricos , Adulto , Humanos , Masculino , Testes de Personalidade , Polônia , Receptores de Dopamina D2/metabolismo , Adulto Jovem
2.
Nature ; 584(7819): 125-129, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32528175

RESUMO

The D2 dopamine receptor (DRD2) is a therapeutic target for Parkinson's disease1 and antipsychotic drugs2. DRD2 is activated by the endogenous neurotransmitter dopamine and synthetic agonist drugs such as bromocriptine3, leading to stimulation of Gi and inhibition of adenylyl cyclase. Here we used cryo-electron microscopy to elucidate the structure of an agonist-bound activated DRD2-Gi complex reconstituted into a phospholipid membrane. The extracellular ligand-binding site of DRD2 is remodelled in response to agonist binding, with conformational changes in extracellular loop 2, transmembrane domain 5 (TM5), TM6 and TM7, propagating to opening of the intracellular Gi-binding site. The DRD2-Gi structure represents, to our knowledge, the first experimental model of a G-protein-coupled receptor-G-protein complex embedded in a phospholipid bilayer, which serves as a benchmark to validate the interactions seen in previous detergent-bound structures. The structure also reveals interactions that are unique to the membrane-embedded complex, including helix 8 burial in the inner leaflet, ordered lysine and arginine side chains in the membrane interfacial regions, and lipid anchoring of the G protein in the membrane. Our model of the activated DRD2 will help to inform the design of subtype-selective DRD2 ligands for multiple human central nervous system disorders.


Assuntos
Microscopia Crioeletrônica , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/química , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/ultraestrutura , Lipídeos de Membrana/metabolismo , Membranas Artificiais , Receptores de Dopamina D2/química , Receptores de Dopamina D2/ultraestrutura , Bromocriptina/química , Bromocriptina/metabolismo , Dopamina/química , Dopamina/metabolismo , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/metabolismo , Humanos , Lipídeos de Membrana/química , Modelos Moleculares , Conformação Proteica , Receptores de Dopamina D2/agonistas , Receptores de Dopamina D2/metabolismo , Transdução de Sinais
3.
Nat Commun ; 11(1): 1957, 2020 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-32327644

RESUMO

Action control is a key brain function determining the survival of animals in their environment. In mammals, neurons expressing dopamine D2 receptors (D2R) in the dorsal striatum (DS) and the nucleus accumbens (Acb) jointly but differentially contribute to the fine regulation of movement. However, their region-specific molecular features are presently unknown. By combining RNAseq of striatal D2R neurons and histological analyses, we identified hundreds of novel region-specific molecular markers, which may serve as tools to target selective subpopulations. As a proof of concept, we characterized the molecular identity of a subcircuit defined by WFS1 neurons and evaluated multiple behavioral tasks after its temporally-controlled deletion of D2R. Consequently, conditional D2R knockout mice displayed a significant reduction in digging behavior and an exacerbated hyperlocomotor response to amphetamine. Thus, targeted molecular analyses reveal an unforeseen heterogeneity in D2R-expressing striatal neuronal populations, underlying specific D2R's functional features in the control of specific motor behaviors.


Assuntos
Neostriado/citologia , Neurônios/fisiologia , Núcleo Accumbens/citologia , Receptores de Dopamina D2/metabolismo , Anfetamina/farmacologia , Animais , Biomarcadores/metabolismo , Corpo Estriado/citologia , Corpo Estriado/metabolismo , Corpo Estriado/fisiologia , Dopaminérgicos/farmacologia , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Atividade Motora/efeitos dos fármacos , Atividade Motora/genética , Neostriado/metabolismo , Neostriado/fisiologia , Vias Neurais , Neurônios/citologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Núcleo Accumbens/metabolismo , Núcleo Accumbens/fisiologia , Receptores de Dopamina D2/genética
4.
PLoS One ; 15(3): e0230647, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32210469

RESUMO

The beneficial effects of omega (ω)-3 polyunsaturated fatty acid (PUFA) supplementation on major depressive disorder have been actively studied, but the underlying mechanism remains unknown. The present study examined the involvement of the nucleus accumbens (NAc) dopaminergic systems in behavioral changes in mice fed a diet high in ω-3 PUFAs. Mice fed a diet containing about double the amount of ω-3 PUFAs (krill oil (KO) diet) exerted shorter immobility times in the forced swim test (FST) than mice fed a control diet, containing only α-linolenic acid (ALA) as ω-3 PUFAs. The shorter immobility times were observed in both male and female mice. A dopamine metabolite, 3,4-dihydroxyphenylacetic acid, increased in the NAc in male mice fed the KO diet when compared with those fed the control diet. In addition, dopamine, 3-methoxytyramine, and homovanillic acid increased in the NAc in female mice fed the KO diet. Notably, the effects of the KO diet on the immobility time in the FST were abolished by microinjection of sulpiride, an antagonist of D2-like receptors, into the NAc. A similar microinjection of an antagonist selective for D1-like receptors, SKF83566, also abolished the reduction in immobility in the FST. Moreover, we found that tyrosine hydroxylase-positive cells increased in the ventral tegmental area (VTA) in mice fed the KO diet. These results suggest that modulation of the VTA-NAc dopaminergic pathway is one of the mechanisms by which a KO diet rich in ω-3 PUFAs reduces the immobility behavior in the mouse FST.


Assuntos
Antidepressivos/farmacologia , Dieta , Ácidos Graxos Ômega-3/farmacologia , Núcleo Accumbens/efeitos dos fármacos , Animais , Antidepressivos/química , Comportamento Animal/efeitos dos fármacos , Monoaminas Biogênicas/análise , Monoaminas Biogênicas/metabolismo , Dopamina/metabolismo , Antagonistas de Dopamina/farmacologia , Ácidos Graxos Ômega-3/química , Feminino , Masculino , Aprendizagem em Labirinto/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Núcleo Accumbens/metabolismo , Receptores de Dopamina D2/metabolismo , Tirosina 3-Mono-Oxigenase/metabolismo , Área Tegmentar Ventral/enzimologia
5.
Nature ; 579(7800): 555-560, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32214250

RESUMO

Dopamine D2 receptors (D2Rs) are densely expressed in the striatum and have been linked to neuropsychiatric disorders such as schizophrenia1,2. High-affinity binding of dopamine suggests that D2Rs detect transient reductions in dopamine concentration (the dopamine dip) during punishment learning3-5. However, the nature and cellular basis of D2R-dependent behaviour are unclear. Here we show that tone reward conditioning induces marked stimulus generalization in a manner that depends on dopamine D1 receptors (D1Rs) in the nucleus accumbens (NAc) of mice, and that discrimination learning refines the conditioning using a dopamine dip. In NAc slices, a narrow dopamine dip (as short as 0.4 s) was detected by D2Rs to disinhibit adenosine A2A receptor (A2AR)-mediated enlargement of dendritic spines in D2R-expressing spiny projection neurons (D2-SPNs). Plasticity-related signalling by Ca2+/calmodulin-dependent protein kinase II and A2ARs in the NAc was required for discrimination learning. By contrast, extinction learning did not involve dopamine dips or D2-SPNs. Treatment with methamphetamine, which dysregulates dopamine signalling, impaired discrimination learning and spine enlargement, and these impairments were reversed by a D2R antagonist. Our data show that D2Rs refine the generalized reward learning mediated by D1Rs.


Assuntos
Espinhas Dendríticas/fisiologia , Aprendizagem por Discriminação/fisiologia , Receptores de Dopamina D2/metabolismo , Animais , Cálcio/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Condicionamento Clássico/efeitos dos fármacos , Espinhas Dendríticas/efeitos dos fármacos , Aprendizagem por Discriminação/efeitos dos fármacos , Dopamina/metabolismo , Antagonistas dos Receptores de Dopamina D2/farmacologia , Extinção Psicológica/efeitos dos fármacos , Masculino , Metanfetamina/antagonistas & inibidores , Metanfetamina/farmacologia , Camundongos , Plasticidade Neuronal , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Núcleo Accumbens/efeitos dos fármacos , Núcleo Accumbens/metabolismo , Optogenética , Receptor A2A de Adenosina/metabolismo , Receptores de Dopamina D1/metabolismo , Recompensa , Transdução de Sinais/efeitos dos fármacos , Sinapses/metabolismo
6.
Clin Interv Aging ; 15: 321-327, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32184581

RESUMO

Objective: Osteoarthritis is the most common type of arthritis and one of the leading causes of job loss and motor disabilities. Recently, the involvement of dopaminergic pathways and dopamine receptor genes has been considered in this disease. Therefore, studying and comparing the expression pattern of these receptor genes can lead to a greater understanding of the pathogenesis of this disease. Methods: In this research, we used the systems biology approach to investigate the role of the dopaminergic pathway in osteoarthritis. Then the gene expression pattern of dopamine receptor genes was examined in an osteoarthritis patientgroup in comparison with healthy individuals by Real-time PCR method. Results: The analysis of the transcriptome dataset of osteoarthritis identified some genes in the dopaminergic pathway and the six most important genes in this disease are in the network with a significant relationship to dopamine receptors which differentially expressed compared to health groups. Statistical analysis of the case control study showed a significant difference (P-value<0.05) in DRD1 and DRD2 family in the patients in comparison to healthy individuals. Discussion: We attained the significant expression pattern of dopamine receptors in the blood of osteoarthritis patients which could be useful to identify new strategies for the diagnosis, management, or treatment of this disease.


Assuntos
Dopamina/metabolismo , Osteoartrite/metabolismo , Receptores Dopaminérgicos/metabolismo , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Receptores de Dopamina D2/metabolismo , Biologia de Sistemas , Transcriptoma
7.
Nat Commun ; 11(1): 1074, 2020 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-32103023

RESUMO

The D2 dopamine receptor (DRD2) is one of the most well-established therapeutic targets for neuropsychiatric and endocrine disorders. Most clinically approved and investigational drugs that target this receptor are known to be subfamily-selective for all three D2-like receptors, rather than subtype-selective for only DRD2. Here, we report the crystal structure of DRD2 bound to the most commonly used antipsychotic drug, haloperidol. The structures suggest an extended binding pocket for DRD2 that distinguishes it from other D2-like subtypes. A detailed analysis of the structures illuminates key structural determinants essential for DRD2 activation and subtype selectivity. A structure-based and mechanism-driven screening combined with a lead optimization approach yield DRD2 highly selective agonists, which could be used as chemical probes for studying the physiological and pathological functions of DRD2 as well as promising therapeutic leads devoid of promiscuity.


Assuntos
Antipsicóticos/farmacologia , Haloperidol/farmacologia , Receptores de Dopamina D2/metabolismo , Receptores de Dopamina D2/ultraestrutura , Cristalografia por Raios X , Humanos , Conformação Proteica/efeitos dos fármacos , Receptores de Dopamina D2/agonistas , Risperidona/metabolismo , Risperidona/farmacologia
8.
Nat Commun ; 11(1): 846, 2020 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-32051403

RESUMO

The development of the striatum dopamine (DA) system through human adolescence, a time of increased sensation seeking and vulnerability to the emergence of psychopathology, has been difficult to study due to pediatric restrictions on direct in vivo assessments of DA. Here, we applied neuroimaging in a longitudinal sample of n = 146 participants aged 12-30. R2', an MR measure of tissue iron which co-localizes with DA vesicles and is necessary for DA synthesis, was assessed across the sample. In the 18-30 year-olds (n = 79) we also performed PET using [11C]dihydrotetrabenazine (DTBZ), a measure of presynaptic vesicular DA storage, and [11C]raclopride (RAC), an indicator of D2/D3 receptor availability. We observed decreases in D2/D3 receptor availability with age, while presynaptic vesicular DA storage (as measured by DTBZ), which was significantly associated with R2' (standardized coefficient = 0.29, 95% CI = [0.11, 0.48]), was developmentally stable by age 18. Our results provide new evidence for maturational specialization of the striatal DA system through adolescence.


Assuntos
Corpo Estriado/diagnóstico por imagem , Corpo Estriado/crescimento & desenvolvimento , Corpo Estriado/metabolismo , Dopamina/metabolismo , Imagem por Ressonância Magnética , Tomografia por Emissão de Pósitrons , Adolescente , Adulto , Fatores Etários , Criança , Neurociência Cognitiva , Feminino , Humanos , Cinética , Masculino , Modelos Biológicos , Neuroimagem , Racloprida , Receptores de Dopamina D2/metabolismo , Receptores de Dopamina D3/metabolismo , Tetrabenazina/análogos & derivados , Adulto Jovem
9.
Nat Commun ; 11(1): 941, 2020 02 18.
Artigo em Inglês | MEDLINE | ID: mdl-32071304

RESUMO

Oxidative stress is a major pathogenic mechanism in Parkinson's disease (PD). As an important cellular antioxidant, glutathione (GSH) balances the production and incorporation of free radicals to protect neurons from oxidative damage. GSH level is decreased in the brains of PD patients. Hence, clarifying the molecular mechanism of GSH deficiency may help deepen our knowledge of PD pathogenesis. Here we report that the astrocytic dopamine D2 receptor (DRD2) regulates GSH synthesis via PKM2-mediated Nrf2 transactivation. In addition we find that pyridoxine can dimerize PKM2 to promote GSH biosynthesis. Further experiments show that pyridoxine supplementation increases the resistance of nigral dopaminergic neurons to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity in wild-type mice as well as in astrocytic Drd2 conditional knockout mice. We conclude that dimerizing PKM2 may be a potential target for PD treatment.


Assuntos
Glutationa/biossíntese , Intoxicação por MPTP/patologia , Fator 2 Relacionado a NF-E2/genética , Fármacos Neuroprotetores/administração & dosagem , Piruvato Quinase/metabolismo , Receptores de Dopamina D2/metabolismo , Animais , Astrócitos , Técnicas de Observação do Comportamento , Comportamento Animal/efeitos dos fármacos , Células Cultivadas , Dopamina/metabolismo , Neurônios Dopaminérgicos , Intoxicação por MPTP/diagnóstico , Intoxicação por MPTP/tratamento farmacológico , Camundongos Knockout , Fator 2 Relacionado a NF-E2/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Cultura Primária de Células , Multimerização Proteica/efeitos dos fármacos , Piridoxina/administração & dosagem , Espécies Reativas de Oxigênio/metabolismo , Receptores de Dopamina D2/genética , Substância Negra/citologia , Substância Negra/efeitos dos fármacos , Substância Negra/patologia , Ativação Transcricional
10.
J Neurosci ; 40(14): 2868-2881, 2020 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-32071139

RESUMO

The neuromodulator dopamine plays a key role in motivation, reward-related learning, and normal motor function. The different affinity of striatal D1 and D2 dopamine receptor types has been argued to constrain the D1 and D2 signaling pathways to phasic and tonic dopamine signals, respectively. However, this view assumes that dopamine receptor kinetics are instantaneous so that the time courses of changes in dopamine concentration and changes in receptor occupation are basically identical. Here we developed a neurochemical model of dopamine receptor binding taking into account the different kinetics and abundance of D1 and D2 receptors in the striatum. Testing a large range of behaviorally-relevant dopamine signals, we found that the D1 and D2 dopamine receptor populations responded very similarly to tonic and phasic dopamine signals. Furthermore, because of slow unbinding rates, both receptor populations integrated dopamine signals over a timescale of minutes. Our model provides a description of how physiological dopamine signals translate into changes in dopamine receptor occupation in the striatum, and explains why dopamine ramps are an effective signal to occupy dopamine receptors. Overall, our model points to the importance of taking into account receptor kinetics for functional considerations of dopamine signaling.SIGNIFICANCE STATEMENT Current models of basal ganglia function are often based on a distinction of two types of dopamine receptors, D1 and D2, with low and high affinity, respectively. Thereby, phasic dopamine signals are believed to mostly affect striatal neurons with D1 receptors, and tonic dopamine signals are believed to mostly affect striatal neurons with D2 receptors. This view does not take into account the rates for the binding and unbinding of dopamine to D1 and D2 receptors. By incorporating these kinetics into a computational model we show that D1 and D2 receptors both respond to phasic and tonic dopamine signals. This has implications for the processing of reward-related and motivational signals in the basal ganglia.


Assuntos
Encéfalo/metabolismo , Modelos Neurológicos , Neurônios/metabolismo , Receptores de Dopamina D1/metabolismo , Receptores de Dopamina D2/metabolismo , Animais , Simulação por Computador , Dopamina/metabolismo , Humanos , Cinética
11.
Psychiatry Clin Neurosci ; 74(4): 263-269, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31943514

RESUMO

AIM: The aim of the study was to test: (i) if D2 /D3 binding in three functional subsections of striatum is different in patients with severe major depressive episodes than in controls; and (ii) if this difference is normalized after electroconvulsive therapy (ECT). METHODS: Nine inpatients were examined with positron emission tomography (PET) and the radioligand [11 C]raclopride before and after an average of 8.4 ECT sessions. Treatment response was assessed using the Montgomery-Åsberg Depression Rating Scale. Nine age- and sex-matched controls were examined twice with PET and [11 C]raclopride. RESULTS: [11 C]raclopride binding was significantly lower in all three subsections of striatum in patients compared to controls (Cohen's dz , 1.14-1.68; P = 0.003-0.027). Montgomery-Åsberg Depression Ratings decreased significantly after ECT (P < 0.001; Cohen's dz , 2.9). ECT had no statistically significant effect on [11 C]raclopride binding, although post-ECT binding estimates were more similar to those obtained in controls in all subsections of striatum. CONCLUSION: Using PET and [11 C]raclopride, we found support for the notion that severe major depressive episodes are associated with significantly lower dopamine D2 /D3 binding in all three subsections of striatum compared to controls. We noted no significant effect on D2 /D3 binding in the patient group after response to ECT.


Assuntos
Transtorno Depressivo Maior , Antagonistas de Dopamina/farmacologia , Eletroconvulsoterapia , Racloprida/farmacologia , Receptores de Dopamina D2 , Receptores de Dopamina D3 , Adulto , Idoso , Mapeamento Encefálico , Radioisótopos de Carbono , Corpo Estriado , Transtorno Depressivo Maior/fisiopatologia , Transtorno Depressivo Maior/terapia , Dopamina/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons , Ligação Proteica , Receptores de Dopamina D2/metabolismo , Receptores de Dopamina D3/metabolismo
12.
Toxicology ; 431: 152367, 2020 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-31945395

RESUMO

Many substances in cigarette smoke can induce changes in DNA methylation. Our previous studies have confirmed paternal nicotine exposure causes hyperactivity in the offspring via mmu-miR-15b. The main aim of the present study is to explore the molecular mechanism underlying the cross-generation effects of paternal nicotine exposure more comprehensively. The male C57BL/6 mice were exposed to 2 mg/kg/d nicotine for 5 weeks, and then mated with wild-type females. The offspring male mice were subjected to behavioral tests at 8 weeks after birth. The results suggested that, paternal nicotine exposure led to hyperactivity in the offspring. An analysis of the changes in DNA methylation revealed that nicotine exposure induced a rise in the total DNA methylation level of Dat in murine spermatozoa, and the hyper-methylation could imprint in the brains of the offspring mice. Then these epigenetic modifications reduced the expression of DAT in the brain of the offspring, resulting in a rise in the level of extracellular dopamine. The activation of D2 receptors caused the dephosphorylation of AKT, which led to increased activation of GSK3α/ß, and ultimately caused hyperactivity in the offspring mice. Further, in wild-type mice, injection of DAT inhibitors simulated this hyperactive phenotype, while the injection of D2s inhibitors reversed the hyperactivity of the offspring caused by paternal nicotine exposure. In conclusion, all results indicated that paternal nicotine exposure could induce hyperactivity in the offspring via the hyper-methylation of Dat. Consequently, Dat may be one of the genes that mediate the cross-generation effects of nicotine besides mmu-mmiR-15b.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/induzido quimicamente , Proteínas da Membrana Plasmática de Transporte de Dopamina/antagonistas & inibidores , Nicotina/toxicidade , Agonistas Nicotínicos/toxicidade , Exposição Paterna/efeitos adversos , Animais , Comportamento Animal/efeitos dos fármacos , Química Encefálica/efeitos dos fármacos , Metilação de DNA , Dopamina/metabolismo , Regulação para Baixo/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Receptores de Dopamina D2/metabolismo , Transdução de Sinais/efeitos dos fármacos , Espermatozoides/efeitos dos fármacos , Espermatozoides/metabolismo
13.
J Agric Food Chem ; 68(7): 1998-2006, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-31984737

RESUMO

Hordenine, a natural constituent of germinated barley, is a biased agonist of the dopamine D2 receptor. This pilot study investigated the biokinetics of hordenine and its metabolites in four volunteers consuming beer equal to 0.075 mg hordenine/kg body weight. A new ultrahigh-performance liquid chromatography method coupled to electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS) method determined maximum plasma concentrations of 12.0-17.3 nM free hordenine after 0-60 min. Hordenine phase-II metabolism was first dominated by sulfation, but later by glucuronidation. The elimination half-lives in plasma were 52.7-66.4 min for free hordenine and about 60/80 min longer for hordenine sulfate and hordenine glucuronide. Urinary excretion peaked 2-3.5 h after consumption and accumulated to 3.78 µmol within 24 h, corresponding to 9.9% of the ingested dose. The observed hordenine levels in plasma seem too low to provoke direct interaction with the dopamine D2 receptor related to food reward, but synergistic or additive effects with alcohol or N-methyltyramine may occur.


Assuntos
Cerveja/análise , Agonistas de Dopamina/farmacocinética , Tiramina/análogos & derivados , Adulto , Cromatografia Líquida de Alta Pressão , Agonistas de Dopamina/sangue , Agonistas de Dopamina/urina , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Receptores de Dopamina D2/química , Receptores de Dopamina D2/metabolismo , Espectrometria de Massas em Tandem , Tiramina/sangue , Tiramina/farmacocinética , Tiramina/urina , Adulto Jovem
14.
Psychopharmacology (Berl) ; 237(4): 1107-1119, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31927604

RESUMO

RATIONALE: Mesolimbic dopamine (DA) signaling is essential for the high maternal caregiving characteristic of the early postpartum period, but little is known about dopamine's role in the expression of maternal caregiving thereafter. OBJECTIVES: We tested the hypothesis that decreased mesolimbic dopaminergic signaling is particularly responsible for the natural decline in maternal caregiving that occurs as the postpartum period progresses. METHODS: Sprague-Dawley (SD) mother rats received intraperitoneal injections of either vehicle, the DA D1 receptor agonist SKF38393, the DA D2 receptor agonist quinpirole, or both agonists twice daily from postpartum days 9 to 15. In a separate experiment involving Long-Evans (LE) rats, we examined whether DA D1 and D2 receptor mRNAs in the nucleus accumbens (NA) shell and ventral tegmental area (VTA), along with DA turnover in the VTA, decline across the postpartum period in parallel with the decreasing maternal behavior. RESULTS: All drug treatments significantly maintained higher frequencies of active maternal behaviors (nesting, pup licking, retrieval) compared to vehicle. Furthermore, the majority of mothers treated with SKF38393 either alone or combined with quinpirole maintained full expression of maternal behavior during behavioral testing. D2 receptor mRNA levels were found to be lower in the late postpartum NA shell and VTA compared to early postpartum, but D1 receptor mRNA levels in the NA shell were higher in the late postpartum period. Furthermore, both late postpartum and recently parturient LE mothers had higher VTA DA turnover compared to nulliparae, suggesting changes in mesolimbic signal-to-noise ratio both at the end and beginning of motherhood. CONCLUSIONS: Collectively, our results suggest that alterations in mesolimbic DA is part of the neural substrate responsible for dynamic maternal caregiving across the entire postpartum period.


Assuntos
Dopamina/metabolismo , Comportamento Materno/fisiologia , Núcleo Accumbens/metabolismo , Período Pós-Parto/metabolismo , Transdução de Sinais/fisiologia , Área Tegmentar Ventral/metabolismo , 2,3,4,5-Tetra-Hidro-7,8-Di-Hidroxi-1-Fenil-1H-3-Benzazepina/farmacologia , Animais , Animais Recém-Nascidos , Agonistas de Dopamina/farmacologia , Antagonistas de Dopamina/farmacologia , Feminino , Masculino , Comportamento Materno/efeitos dos fármacos , Comportamento Materno/psicologia , Núcleo Accumbens/efeitos dos fármacos , Período Pós-Parto/efeitos dos fármacos , Período Pós-Parto/psicologia , Gravidez , Quimpirol/farmacologia , Ratos , Ratos Sprague-Dawley , Receptores de Dopamina D1/agonistas , Receptores de Dopamina D1/antagonistas & inibidores , Receptores de Dopamina D1/metabolismo , Receptores de Dopamina D2/agonistas , Receptores de Dopamina D2/metabolismo , Transdução de Sinais/efeitos dos fármacos , Área Tegmentar Ventral/efeitos dos fármacos
15.
Biochem Pharmacol ; 174: 113791, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31917245

RESUMO

Protein kinase C (PKC) is one of the major effectors involved in the heterologous regulatory pathways of G protein-coupled receptors (GPCRs). On the other hand, GRK2 and ß-arrestins are the players of homologous regulatory pathway of GPCRs that affect the receptor functions in agonist-selective manner. Even though two pathways can occur independently, crosstalks between two pathways add more diverse modes of regulations on GPCR functions. Even if extensive studies have been conducted, a commonly applicable molecular mechanism involved in the crosstalks between two regulatory pathways has yet to be elucidated. Here we show that PKCßII was phosphorylated at its activation loop of kinase domain (T500) through constitutive interaction with phosphoinositide-dependent kinase 1 (PDK1) that is phosphorylated at S214. With agonist stimulation, dopamine D2 receptor interacted with 14-3-3η in GRK2/ß-arrestin2-dependent manner, resulting in the recruitment of PDK1. The PDK1 recruited to 14-3-3η was dephosphorylated at S241 and dissociated from PKCßII, abrogating the phosphorylation of PKCßII at T500. This signaling cascade resulted in the inhibition of PKCßII functions, including its phosphorylation in the C-terminal tail, intracellular translocation, and kinase activity. Thus, this study revealed a novel and commonly applicable molecular mechanism involved in the inhibition of PKCßII functions through GRK2/ß-arrestin2-mediated homologous pathway of GPCRs. The results obtained in this study could be expanded to other GPCRs and provide new strategies for the treatment of PKCßII-related disorders.


Assuntos
Proteínas Quinases Dependentes de 3-Fosfoinositídeo/metabolismo , Quinase 2 de Receptor Acoplado a Proteína G/metabolismo , Proteína Quinase C beta/metabolismo , Receptores de Dopamina D2/metabolismo , beta-Arrestina 2/metabolismo , Proteínas 14-3-3/metabolismo , Agonistas de Dopamina/farmacologia , Células HEK293 , Humanos , Fosforilação , Transdução de Sinais
16.
Mol Pharmacol ; 97(2): 123-131, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31734646

RESUMO

The dopamine D2 receptor (D2R) is a G protein-coupled receptor (GPCR) expressed in regions of the brain that control motor function, cognition, and motivation. As a result, D2R is involved in the pathophysiology of disorders such as schizophrenia and drug addiction. Understanding the signaling pathways activated by D2R is crucial to finding new therapeutic targets for these disorders. D2R stimulation by its agonist, dopamine, causes desensitization and internalization of the receptor. A previous study found that inhibitors of the receptor tyrosine kinase anaplastic lymphoma kinase (ALK) blocked D2R desensitization in neurons in the ventral tegmental area of the brain. In the present study, using a cell-based system, we investigated whether ALK regulates D2R internalization. The ALK inhibitor alectinib completely inhibited dopamine-induced D2R internalization. Since GPCRs can transactivate receptor tyrosine kinases, we also examined if D2R stimulation activated ALK signaling. ALK phosphorylation increased by almost 2-fold after dopamine treatment and ALK coimmunoprecipitated with D2R. To identify the signaling pathways downstream of ALK that might regulate D2R internalization, we used pharmacological inhibitors of proteins activated by ALK signaling. Protein kinase Cγ was activated by dopamine in an ALK-dependent manner, and a protein kinase C inhibitor completely blocked dopamine-induced D2R internalization. Taken together, these results identify ALK as a receptor tyrosine kinase transactivated by D2R that promotes its internalization, possibly through activation of protein kinase C. ALK inhibitors could be useful in enhancing D2R signaling. SIGNIFICANCE STATEMENT: Receptor internalization is a mechanism by which receptors are desensitized. In this study we found that agonist-induced internalization of the dopamine D2 receptor is regulated by the receptor tyrosine kinase ALK. ALK was also transactivated by and associated with dopamine D2 receptor. Dopamine activated protein kinase C in an ALK-dependent manner and a PKC inhibitor blocked dopamine D2 receptor internalization. These results indicate that ALK regulates dopamine D2 receptor trafficking, which has implications for psychiatric disorders involving dysregulated dopamine signaling.


Assuntos
Quinase do Linfoma Anaplásico/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Receptores de Dopamina D2/metabolismo , Transdução de Sinais/efeitos dos fármacos , Quinase do Linfoma Anaplásico/antagonistas & inibidores , Carbazóis/farmacologia , Dopamina/farmacologia , Células HEK293 , Humanos , Fosforilação/efeitos dos fármacos , Piperidinas/farmacologia , Proteína Quinase C/antagonistas & inibidores , Proteína Quinase C/metabolismo , RNA Interferente Pequeno/metabolismo , Receptores de Dopamina D1/genética , Receptores de Dopamina D1/metabolismo , Receptores de Dopamina D2/agonistas , Receptores de Dopamina D2/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
18.
J Pharmacol Exp Ther ; 372(3): 267-276, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31857349

RESUMO

Heterologous sensitization of adenylyl cyclase (AC) is revealed as enhanced or exaggerated AC/cAMP signaling that occurs following persistent activation of Gα i/o-coupled receptors. This paradoxical phenomenon was discovered more than 40 years ago and was proposed as a cellular mechanism to explain the adaptive changes that occur following chronic exposure to drugs of abuse. However, the underlying molecular mechanisms of heterologous sensitization of AC remain largely unknown. In the present study, we performed a genome-wide cell-based RNA interference screen as an unbiased approach to identify genes associated with heterologous sensitization of AC. Following a series of validation and confirmation assays, three genes that form an E3 ligase complex, cullin3 (CUL3), neural precursor-cell-expressed and developmentally downregulated 8 (NEDD8), and really interesting new gene (RING)-box protein 1 (RBX1), were identified as specific modulators of heterologous sensitization of AC. Furthermore, based on the downstream actions of these genes, we evaluated the activity of proteasome inhibitors as well as the specific NEDD8-activating enzyme inhibitor, MLN4924 (Pevonedistat), in AC sensitization. We demonstrate that MG-132 and bortezomib treatments could mimic the inhibitory effects observed with gene knockdown, and MLN4924 was potent and efficacious in blocking the development of heterologous sensitization of endogenous and recombinant AC isoforms, including AC1, AC2, AC5, and AC6. Together, by using genetic and pharmacological approaches, we identified, for the first time, cullin3-RING ligases and the protein degradation pathway as essential modulators for heterologous sensitization of AC. SIGNIFICANCE STATEMENT: Through a genome-wide cell-based RNA interference screening, we identified three genes that form an E3 ligase complex, cullin3, neural precursor-cell-expressed and developmentally downregulated 8 (NEDD8), and really interesting new gene-box protein 1, as specific modulators of heterologous sensitization of AC. The effect of cullin3, NEDD8, or really interesting new gene-box protein 1 small interfering RNAs on heterologous sensitization was recapitulated by proteasome inhibitors, MG132 and bortezomib, and the specific NEDD8-activating enzyme inhibitor, MLN4924. These results suggest a novel hypothesis in which protein degradation is involved in the sensitization of AC signaling that occurs following chronic activation of Gαi/o-coupled receptors.


Assuntos
Adenilil Ciclases/metabolismo , Proteínas de Transporte/genética , Proteínas Culina/genética , Proteína NEDD8/genética , Ubiquitina-Proteína Ligases/genética , Inibidores de Adenilil Ciclases/farmacologia , Adenilil Ciclases/genética , Sobrevivência Celular/efeitos dos fármacos , AMP Cíclico/metabolismo , Ciclopentanos/farmacologia , Ativação Enzimática , Técnicas de Silenciamento de Genes , Estudo de Associação Genômica Ampla , Células HEK293 , Humanos , Pirimidinas/farmacologia , RNA Interferente Pequeno , Receptores de Dopamina D2/genética , Receptores de Dopamina D2/metabolismo , Transdução de Sinais
19.
Int J Mol Sci ; 20(23)2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31816953

RESUMO

It was previously demonstrated that rat adenosine A2AR transmembrane V peptide administration into the nucleus accumbens enhances cocaine self-administration through disruption of the A2AR-dopamine (D2R) heteroreceptor complex of this region. Unlike human A2AR transmembrane 4 (TM4) and 5 (TM5), A2AR TM2 did not interfere with the formation of the A2AR-D2R heteroreceptor complex in cellular models using BRET1 assay. A2AR TM2 was proposed to be part of the of the receptor interface of the A2AR homomer instead and was therefore tested in the current article for effects on rat cocaine self-administration using rat A2AR synthetic TM2 peptide bilaterally injected into the nucleus accumbens. The injected A2AR TM2 peptide failed to significantly counteract the inhibitory action of the A2AR agonist CGS 21680 (0.1 mg/Kg) on cocaine self-administration. In line with these results, the microinjected A2AR TM2 peptide did not reduce the number of proximity ligation assay blobs identifying A2AR-D2R heteroreceptor complexes in the nucleus accumbens. In contrast, the A2AR TM2 peptide significantly reduced the number of A2AR-A2AR homoreceptor complexes in the nucleus accumbens. As to effects on the receptor-receptor interactions in the A2AR-D2R heteroreceptor complexes, the A2AR TM2 peptide did not alter the significant increase in the D2R Ki, high values produced by the A2AR agonist CGS 21680 ex vivo in the ventral striatum. The results indicate that the accumbal A2AR-A2AR homomeric complexes are not involved in mediating the A2AR agonist-induced inhibition of cocaine self-administration.


Assuntos
Membrana Celular/química , Cocaína/administração & dosagem , Peptídeos/administração & dosagem , Receptor A2A de Adenosina/química , Receptor A2A de Adenosina/metabolismo , Receptores de Dopamina D2/metabolismo , Autoadministração , Adenosina/análogos & derivados , Adenosina/farmacologia , Agonistas do Receptor A2 de Adenosina/farmacologia , Animais , Masculino , Microinjeções , Modelos Moleculares , Núcleo Accumbens/efeitos dos fármacos , Fenetilaminas/farmacologia , Multimerização Proteica/efeitos dos fármacos , Quimpirol/farmacologia , Racloprida/farmacologia , Ratos Sprague-Dawley
20.
PLoS Biol ; 17(10): e3000477, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31600280

RESUMO

The striatum plays a fundamental role in motor learning and reward-related behaviors that are synergistically shaped by populations of D1 dopamine receptor (D1R)- and D2 dopamine receptor (D2R)-expressing medium spiny neurons (MSNs). How various neurotransmitter inputs converging on common intracellular pathways are parsed out to regulate distinct behavioral outcomes in a neuron-specific manner is poorly understood. Here, we reveal that distinct contributions of D1R-MSNs and D2R-MSNs towards reward and motor behaviors are delineated by the multifaceted signaling protein neurofibromin 1 (NF1). Using genetic mouse models, we show that NF1 in D1R-MSN modulates opioid reward, whereas loss of NF1 in D2R-MSNs delays motor learning by impeding the formation and consolidation of repetitive motor sequences. We found that motor learning deficits upon NF1 loss were associated with the disruption in dopamine signaling to cAMP in D2R-MSN. Restoration of cAMP levels pharmacologically or chemogenetically rescued the motor learning deficits seen upon NF1 loss in D2R-MSN. Our findings illustrate that multiplex signaling capabilities of MSNs are deployed at the level of intracellular pathways to achieve cell-specific control over behavioral outcomes.


Assuntos
Corpo Estriado/fisiologia , Neurofibromina 1/metabolismo , Neurônios/fisiologia , Animais , AMP Cíclico/metabolismo , Dopamina/metabolismo , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Modelos Animais , Atividade Motora/fisiologia , Neurônios/metabolismo , Receptores de Dopamina D1/metabolismo , Receptores de Dopamina D2/metabolismo , Recompensa , Transdução de Sinais
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