Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 4.573
Filtrar
1.
Biochem Pharmacol ; 180: 114136, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32628930

RESUMO

Oridonin is a diterpene compound that regulates the activity of PPAR-γ (peroxisome proliferator-activated receptor gamma) transcription factor. Cumulative evidence indicates that AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid)-type glutamate receptors (AMPARs) play an important role in the treatment of depression. In the article, we found that after treatment with oridonin, the immobility time of mice was significantly reduced in the tail suspension test (TST) and the forced-swim test (FST). After five consecutive days of treatment in mice, oridonin significantly enhanced the expression of PPAR-γ, GluA1 (Ser845) phosphorylation, and GluA1 in the total protein extract of the prefrontal cortex (PFC). Blocking PPAR-γ was able to block antidepressant effects of oridonin. In synaptosome fractions of the PFC, oridonin treatment also significantly increased the GluA1 (Ser845) phosphorylation and GluA1 levels. Moreover, antidepressant actions of oridonin were blocked by AMPA receptor-specific antagonist GYKI 52466. This study demonstrates that oridonin regulates PPAR-γ/AMPA receptor signaling in the prefrontal cortex, and that oridonin can be identified as a novel antidepressant with clinical potential.


Assuntos
Antidepressivos/farmacologia , Comportamento Animal/efeitos dos fármacos , Depressão/tratamento farmacológico , Diterpenos de Caurano/farmacologia , PPAR gama/metabolismo , Receptores de AMPA/metabolismo , Animais , Antidepressivos/administração & dosagem , Depressão/metabolismo , Depressão/psicologia , Modelos Animais de Doenças , Diterpenos de Caurano/administração & dosagem , Masculino , Camundongos , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/metabolismo , Transdução de Sinais , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/metabolismo
2.
J Headache Pain ; 21(1): 83, 2020 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-32615921

RESUMO

BACKGROUND: Purine receptors play roles in peripheral and central sensitization and are associated with migraine headache. We investigated the possibility that ATP plays a permissive role in the activation of AMPA receptors thus inducing Glu release from nerve terminals isolated from the rat trigeminal caudal nucleus (TCN). METHODS: Nerve endings isolated from the rat TCN were loaded with [3H]D-aspartic acid ([3H]D-ASP), layered into thermostated superfusion chambers, and perfused continuously with physiological medium, alone or with various test drugs. Radioactivity was measured to assess [3H]D-ASP release under different experimental conditions. RESULTS: Synaptosomal [3H]D-ASP spontaneous release was stimulated by ATP and to an even greater extent by the ATP analogue benzoylbenzoylATP (BzATP). The stimulation of [3H]D-ASP basal release by the purinergic agonists was prevented by the selective P2X7 receptor antagonist A438079. AMPA had no effect on basal [3H]D-ASP release, but the release observed when synaptosomes were exposed to AMPA plus a purinoceptor agonist exceeded that observed with ATP or BzATP alone. The selective AMPA receptor antagonist NBQX blocked this "excess" release. Co-exposure to AMPA and BzATP, each at a concentration with no release-stimulating effects, evoked a significant increase in [3H]D-ASP basal release, which was prevented by exposure to a selective AMPA antagonist. CONCLUSIONS: P2X7 receptors expressed on glutamatergic nerve terminals in the rat TCN can mediate Glu release directly and indirectly by facilitating the activation of presynaptic AMPA receptors. The high level of glial ATP that occurs during chronic pain states can promote widespread release of Glu as well as can increase the function of AMPA receptors. In this manner, ATP contributes to the AMPA receptor activation involved in the onset and maintenance of the central sensitization associated with chronic pain.


Assuntos
Terminações Nervosas/efeitos dos fármacos , Terminações Nervosas/metabolismo , Receptores de AMPA/metabolismo , Receptores Pré-Sinápticos/metabolismo , Receptores Purinérgicos P2X7/fisiologia , Núcleo Inferior Caudal do Nervo Trigêmeo/metabolismo , Animais , Antagonistas de Aminoácidos Excitatórios/farmacologia , Masculino , Agonistas do Receptor Purinérgico P2X , Antagonistas do Receptor Purinérgico P2X/farmacologia , Ratos , Transmissão Sináptica , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/metabolismo
3.
Sci Rep ; 10(1): 8626, 2020 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-32451470

RESUMO

The study of postsynaptic excitation to inhibition (E/I ratio) imbalances in human brain diseases, is a highly relevant functional measurement poorly investigated due to postmortem degradation of synaptic receptors. We show that near-simultaneous recording of microtransplanted synaptic receptors after simulated morgue conditions allows the determination of the postsynaptic E/I ratio for at least 120 h after death, expanding the availability and use of human diseased tissue stored in brain banks.


Assuntos
Encéfalo/fisiologia , Potenciais Pós-Sinápticos Excitadores/fisiologia , Potenciais Pós-Sinápticos Inibidores/fisiologia , Adulto , Animais , Encefalopatias/patologia , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Feminino , Humanos , Potenciais Pós-Sinápticos Inibidores/efeitos dos fármacos , Ácido Caínico/farmacologia , Masculino , Oócitos/citologia , Oócitos/metabolismo , Ratos , Ratos Wistar , Receptores de Neurotransmissores/metabolismo , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/fisiologia , Temperatura , Fatores de Tempo , Ácido gama-Aminobutírico/farmacologia
4.
Toxicology ; 440: 152492, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32407874

RESUMO

Neurotoxicity induced by exposure to heavy metal lead (Pb) is a concern of utmost importance particularly for countries with industrial-based economies. The developing brain is especially sensitive to exposure to even minute quantities of Pb which can alter neurodevelopmental trajectory with irreversible effects on motor, emotive-social and cognitive attributes even into later adulthood. Chemical synapses form the major pathway of inter-neuronal communications and are prime candidates for higher order brain (motor, memory and behavior) functions and determine the resistance/susceptibility for neurological disorders, including neuropsychopathologies. The synaptic pathways and mechanisms underlying Pb-mediated alterations in neuronal signaling and plasticity are not completely understood. Employing a biochemically isolated synaptosomal fraction which is enriched in synaptic terminals and synaptic mitochondria, this study aimed to analyze the alterations in bioenergetic and redox/antioxidant status of cerebellar synapses induced by developmental exposure to Pb (0.2 %). Moreover, we test the efficacy of vitamin C (ascorbate; 500 mg/kg body weight), a neuroprotective and neuromodulatory antioxidant, in mitigation of Pb-induced neuronal deficits. Our results implicate redox and bioenergetic disruptions as an underlying feature of the synaptic dysfunction observed in developmental Pb neurotoxicity, potentially contributing to consequent deficits in motor, behavioral and psychological attributes of the organisms. In addition, we establish ascorbate as a key ingredient for therapeutic approach against Pb induced neurotoxicity, particularly for early-life exposures.


Assuntos
Antioxidantes/uso terapêutico , Ácido Ascórbico/uso terapêutico , Cerebelo/metabolismo , Metabolismo Energético/efeitos dos fármacos , Intoxicação do Sistema Nervoso por Chumbo/patologia , Sinapses/metabolismo , Animais , Antioxidantes/farmacologia , Ácido Ascórbico/farmacologia , Cerebelo/efeitos dos fármacos , Feminino , Glutationa/metabolismo , Chumbo/sangue , Intoxicação do Sistema Nervoso por Chumbo/psicologia , Masculino , Fármacos Neuroprotetores/farmacologia , Fármacos Neuroprotetores/uso terapêutico , Tamanho do Órgão/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Gravidez , Ratos , Ratos Wistar , Sinapses/efeitos dos fármacos , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/metabolismo
5.
Nat Prod Res ; 34(4): 511-517, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30470136

RESUMO

A new tetracyclic saponin, 17(R),20(R)-3ß,6α,16ß-trihydroxycycloartanyl-23-carboxylic acid 16-lactone 3-O-ß-D-glucopyranoside (1) together with one known flavonoid, camelliaside A (2) were isolated from the aerial parts of Astragalus glycyphyllos L. Their structures were determined by chemical, HRESIMS and NMR methods. On 6-hydroxydopamine in vitro model on isolated rat brain synaptosomes, compounds 1-2 had statistically significant neuroprotective activity similar to that of Silibinin, tested at 100 µM. Saponin 1 possessed the most prominent neuroprotective and antioxidant effects in this in vitro model. On human recombinant monoamine oxidase type B enzyme compound 1 displayed strong inhibiting activity, compared to Selegiline (1 µM). It could be concluded that the new epoxycycloartane saponin 1 could be a promising leading structure in respect of neurodegenerative diseases.


Assuntos
Astrágalo (Planta)/química , Saponinas/isolamento & purificação , Animais , Antioxidantes/química , Antioxidantes/isolamento & purificação , Antioxidantes/farmacologia , Flavonoides/química , Flavonoides/isolamento & purificação , Flavonoides/farmacologia , Humanos , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Monoaminoxidase/efeitos dos fármacos , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/isolamento & purificação , Fármacos Neuroprotetores/farmacologia , Ratos , Saponinas/química , Saponinas/farmacologia , Sinaptossomos/efeitos dos fármacos
6.
Med Chem ; 16(3): 326-339, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31146671

RESUMO

OBJECTIVE: The syntheses and biological activities of 8-thiosubstituted-1,3,7- trimethylxanthine derivatives bearing an aromatic hydrazide-hydrazone fragment in the side chain at C8 are described. METHODS: The chemical structures of the synthesized compounds 6a-m were confirmed based on their MS, FTIR, 1H NMR and 13C NMR analyses. RESULTS: The in vitro investigations of neuroprotective effects manifested on cellular (human neuroblastoma cell line SH-SY5Y) and sub-cellular (isolated rat brain synaptosomes) levels show that compounds 6g and 6i demonstrate statistically significant activity. The performed monoamine oxidase B (MAO-B) inhibition study in vitro show that compounds 6g and 6i possess a significant MAO-B inhibition activity close to L-deprenyl. CONCLUSION: These results suggest that such compounds may be utilized for the development of new candidate MAO-B inhibitors for the treatment of Parkinson's disease.


Assuntos
Antiparkinsonianos/farmacologia , Hidrazonas/farmacologia , Inibidores da Monoaminoxidase/farmacologia , Fármacos Neuroprotetores/farmacologia , Xantinas/farmacologia , Animais , Antiparkinsonianos/síntese química , Desenho de Fármacos , Humanos , Hidrazonas/síntese química , Inibidores da Monoaminoxidase/síntese química , Neuroproteção/efeitos dos fármacos , Fármacos Neuroprotetores/síntese química , Ratos , Sinaptossomos/efeitos dos fármacos , Xantinas/síntese química
7.
Spectrochim Acta A Mol Biomol Spectrosc ; 228: 117535, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-31748152

RESUMO

Aluminium (Al) is reported to promote free radical production, decrease the antioxidant enzyme status and disturb the enzyme activity involved in acetylcholine metabolism leading to cognitive dysfunction that are strongly associated with Alzheimer's disease (AD) pathogenesis. This work aimed at investigating the effect of Al-toxicity on synaptosomal membrane biophysical properties and lipid peroxidation during 65 days. We utilized ATR-IR spectroscopy to study the changes in membrane biochemical structure and biophysical properties of isolated rat cortical synaptosomes, and EPR spin trapping and labeling to follow NADPH oxidase activity and changes of membrane order parameter, respectively. The results showed increase in membrane fluidity and disorder in early 21d of AlCl3 treatment, while after 42d the membrane rigidity, packing, and order increased. The late (65d) an increase in the amount of unsaturated fatty acids, the accumulation of lipid peroxide end products, and ROS production were detected in rat cortex synaptosomes mediated by Al toxicity and oxidative stress (OS). A dramatic increase was also detected in Ca2+ level, synaptic membrane polarity, and EPR-detected order S-parameter. These outcomes strongly suggest that the synaptosomal membrane phospholipids underwent free radical attacks mediated by AlCl3 due to greater NOX activity, and the release of synaptic vesicles into synaptic cleft might be hindered. The adopted spectroscopic techniques have shed light on the biomolecular structure and membrane biophysical changes of isolated cortical synaptosomes for the first time, allowing researchers to move closer to a complete understanding of pathological tissues.


Assuntos
Alumínio/toxicidade , Córtex Cerebral/patologia , Estresse Fisiológico , Sinaptossomos/patologia , Animais , Cálcio/metabolismo , Análise por Conglomerados , Espectroscopia de Ressonância de Spin Eletrônica , Hidrocarbonetos/química , Íons , Lipídeos/química , Masculino , Ratos Wistar , Espectrofotometria Infravermelho , Estresse Fisiológico/efeitos dos fármacos , Sinaptossomos/efeitos dos fármacos
8.
J Mol Neurosci ; 70(1): 112-119, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31643037

RESUMO

Ketoacidosis is a dangerous complication of diabetes mellitus in which plasma levels of ketone bodies can reach 20-25 mM. This condition is life-threatening. In contrast, a ketogenic diet, achieving plasma levels of ketone bodies of about 4-5 mM, can be used for treating different brain diseases. However, the factors leading to the conversion of the neuroprotective ketone bodies' action to the neurotoxic action during ketoacidosis are still unknown. We investigated the influence of high concentration (25 mM) of the main ketone body, ß-hydroxybutyrate (BHB), on intrasynaptosomal pH (pHi), synaptic vesicle cycle, plasma membrane, and mitochondrial potentials. Using the fluorescent dye BCECF-AM, it was shown that BHB at concentrations of 8 and 25 mM did not influence pHi in synaptosomes. By means of the fluorescent dye acridine orange, it was demonstrated that 25 mM of BHB had no effect on exocytosis but inhibited compensatory endocytosis by 5-fold. Increasing buffer capacity with 25 mM HEPES did not affect endocytosis. Glucose abolished BHB-induced endocytosis inhibition. Using the fluorescent dye DiSC3(5), it was shown that 25 mM of BHB induced a significant plasma membrane depolarization. This effect was not impacted by glucose. Using the fluorescent dye rhodamine-123, it was shown that BHB alone (25 mМ) did not alter the potential of intrasynaptosomal mitochondria.Importantly, the high concentration of BHB (25 mМ) causes the depolarization of the plasma membrane and stronger inhibition of endocytosis compared with the intermediate concentration (8 mM).


Assuntos
Ácido 3-Hidroxibutírico/farmacologia , Cetose/metabolismo , Potenciais da Membrana , Vesículas Sinápticas/metabolismo , Sinaptossomos/metabolismo , Animais , Encéfalo/citologia , Encéfalo/metabolismo , Endocitose , Exocitose , Concentração de Íons de Hidrogênio , Masculino , Ratos , Ratos Wistar , Vesículas Sinápticas/efeitos dos fármacos , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/fisiologia
9.
Biochem Pharmacol ; 174: 113786, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31887288

RESUMO

Neuronal nicotinic acetylcholine receptors (nAChRs) are crucial mediators of central presynaptic, postsynaptic, and extrasynaptic signaling, and they are implicated in a range of CNS disorders. The numerous nAChR subtypes are differentially expressed and mediate distinct functions throughout the CNS, and thus there is considerable interest in developing subtype-selective nAChR modulators, both for use as pharmacological tools and as putative therapeutics. α6ß2-containing (α6ß2*) nAChRs are highly expressed in and regulate the activity of midbrain dopaminergic neurons, which makes them attractive drug targets in several psychiatric and neurological diseases, including nicotine addiction and Parkinson's disease. This paper presents the preclinical characterization of AN317, a novel α6ß2* agonist exhibiting functional selectivity toward other nAChRs, including α4ß2, α3ß4 and α7 receptors. AN317 induced [3H]dopamine release from rat striatal synaptosomes and augmented dopaminergic neuron activity in substantia nigra pars compacta brain slices in Ca2+ imaging and electrophysiological assays. In line with this, AN317 alleviated the high-frequency tremors arising from reserpine-mediated dopamine depletion in rats. Finally, AN317 mediated significant protective effects on cultured rat mesencephalic neurons treated with the dopaminergic neurotoxin MPP+. AN317 displays good bioavailability and readily crosses the blood-brain barrier, which makes it a unique tool for both in vitro and in vivo studies of native α6ß2* receptors in the nigrostriatal system and other dopaminergic pathways. Altogether, these findings highlight the potential of selective α6ß2* nAChR activation as a treatment strategy for symptoms and possibly even deceleration of disease progression in neurodegenerative diseases such as Parkinson's disease.


Assuntos
Fármacos Neuroprotetores/farmacologia , Agonistas Nicotínicos/farmacologia , Receptores Nicotínicos/metabolismo , Potenciais de Ação/efeitos dos fármacos , Animais , Sinalização do Cálcio/efeitos dos fármacos , Dopamina/metabolismo , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Células HEK293 , Humanos , Masculino , Mesencéfalo/efeitos dos fármacos , Mesencéfalo/embriologia , Camundongos , Fármacos Neuroprotetores/administração & dosagem , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/farmacocinética , Agonistas Nicotínicos/administração & dosagem , Agonistas Nicotínicos/química , Agonistas Nicotínicos/farmacocinética , Oócitos/efeitos dos fármacos , Oócitos/metabolismo , Técnicas de Patch-Clamp , Ligação Proteica , Ratos , Ratos Sprague-Dawley , Ratos Wistar , Receptores Nicotínicos/genética , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/metabolismo , Xenopus laevis
10.
Biochem Pharmacol ; 174: 113788, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31887290

RESUMO

α6ß2-Containing nicotinic acetylcholine receptors (α6ß2* nAChRs) are predominantly expressed in midbrain dopaminergic neurons, including substantia nigra pars compacta (SNc) neurons and their projections to striatal regions, where they regulate dopamine release and nigrostriatal activity. It is well established that nAChR agonists exert protection against dopaminergic neurotoxicity in cellular assays and parkinsonian animal models. Historically, drug development in the nAChR field has been mostly focused on development of selective agonists and positive allosteric modulators (PAMs) for the predominant neuronal nAChRs, α7 and α4ß2. Here, we report the discovery and characterization of AN6001, a novel selective α6ß2* nAChR PAM. AN6001 mediated increases in both nicotine potency and efficacy at the human α6/α3ß2ß3V9'S nAChR in HEK293 cells, and it positively modulated ACh-evoked currents through both α6/α3ß2ß3V9'S and a concatenated ß3-α6-ß2-α6-ß2 receptor in Xenopus oocytes, displaying EC50 values of 0.58 µM and 0.40 µM, respectively. In contrast, the compound did not display significant modulatory activity at α4ß2, α3ß4, α7 and muscle nAChRs. AN6001 also increased agonist-induced dopamine release from striatal synaptosomes and augmented agonist-induced global cellular responses and inward currents in dopaminergic neurons in SNc slices (measured by Ca2+ imaging and patch clamp recordings, respectively). Finally, AN6001 potentiated the neuroprotective effect of nicotine at MPP+-treated primary dopaminergic neurons. Overall, our studies demonstrate the existence of allosteric sites on α6ß2* nAChRs and that positive modulation of native α6ß2* receptors strengthens DA signaling. Hence, AN6001 represents an important tool for studies of α6ß2* nAChRs and furthermore underlines the therapeutic potential in these receptors in Parkinson's disease.


Assuntos
Regulação Alostérica/efeitos dos fármacos , Dopamina/metabolismo , Fármacos Neuroprotetores/farmacologia , Receptores Nicotínicos/metabolismo , Potenciais de Ação/efeitos dos fármacos , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Sinalização do Cálcio/efeitos dos fármacos , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/metabolismo , Células HEK293 , Humanos , Camundongos , Fármacos Neuroprotetores/química , Nicotina/farmacologia , Oócitos/efeitos dos fármacos , Técnicas de Patch-Clamp , Ratos Sprague-Dawley , Ratos Wistar , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/metabolismo , Xenopus laevis
11.
Sci Rep ; 9(1): 18342, 2019 12 04.
Artigo em Inglês | MEDLINE | ID: mdl-31797996

RESUMO

Current approaches in treatment of Alzheimer's disease (AD) is focused on early stages of cognitive decline. Identifying therapeutic targets that promote synaptic resilience during early stages may prevent progressive memory deficits by preserving memory mechanisms. We recently reported that the inducible isoform of phospholipase D (PLD1) was significantly increased in synaptosomes from post-mortem AD brains compared to age-matched controls. Using mouse models, we reported that the aberrantly elevated neuronal PLD1 is key for oligomeric amyloid driven synaptic dysfunction and underlying memory deficits. Here, we demonstrate that chronic inhibition using a well-tolerated PLD1 specific small molecule inhibitor is sufficient to prevent the progression of synaptic dysfunction during early stages in the 3xTg-AD mouse model. Firstly, we report prevention of cognitive decline in the inhibitor-treated group using novel object recognition (NOR) and fear conditioning (FC). Secondly, we provide electrophysiological assessment of better synaptic function in the inhibitor-treated group. Lastly, using Golgi staining, we report that preservation of dendritic spine integrity as one of the mechanisms underlying the action of the small molecule inhibitor. Collectively, these studies provide evidence for inhibition of PLD1 as a potential therapeutic strategy in preventing progression of cognitive decline associated with AD and related dementia.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Encéfalo/diagnóstico por imagem , Fosfolipase D/genética , Bibliotecas de Moléculas Pequenas/farmacologia , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/fisiopatologia , Peptídeos beta-Amiloides/genética , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/fisiopatologia , Disfunção Cognitiva/tratamento farmacológico , Disfunção Cognitiva/genética , Disfunção Cognitiva/patologia , Modelos Animais de Doenças , Humanos , Camundongos , Neurônios/efeitos dos fármacos , Neurônios/patologia , Fosfolipase D/antagonistas & inibidores , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/patologia , Proteínas tau/genética
12.
Eur J Pharmacol ; 865: 172781, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31706856

RESUMO

Inhibiting glutamate release can reduce neuronal excitability and is recognized as a key mechanism of anti-epileptic drugs. In this study, by using isolated nerve terminal (synaptosome) and slice preparations, we investigated the effect of asiatic acid, a triterpene isolated from Centella asiatica with antiepileptic activity, on glutamate release in the hippocampus of rats. In hippocampal synaptosomes, application of asiatic acid resulted in a concentration-dependent inhibition of 4-aminopyridine-evoked glutamate release. This inhibitory action was dependent on extracellular calcium, blocked by inhibiting the vesicular transporter, but was unaffected by inhibiting the glutamate transporter. In addition, asiatic acid decreased the 4-aminopyridine-induced increase in the intraterminal calcium and failed to alter the synaptosomal potential. Furthermore, the asiatic acid-mediated release inhibition was significantly suppressed by the N- and P/Q-type calcium channel inhibitor ω-conotoxin MVIIC or protein kinase C inhibitor GF109203X. Western blotting data in synaptosomes also revealed that asiatic acid reduced 4-aminopyridine-induced phosphorylation of protein kinase C. In hippocampal slices, asiatic acid decreased the frequencies of spontaneous excitatory postsynaptic currents without changing their amplitudes and glutamate-activated currents in CA3 pyramidal neurons. We also observed that asiatic acid significantly suppressed 4-aminopyridine-induced burst firing. These data suggest that, in rat hippocampal nerve terminals, asiatic acid attenuates the calcium influx via N- and P/Q-type calcium channels, subsequently suppressing protein kinase C activity and decreasing glutamate release.


Assuntos
Ácido Glutâmico/metabolismo , Hipocampo/efeitos dos fármacos , Triterpenos Pentacíclicos/farmacologia , 4-Aminopiridina/farmacologia , Animais , Cálcio/metabolismo , Centella , Hipocampo/metabolismo , Hipocampo/fisiologia , Indóis/farmacologia , Masculino , Maleimidas/farmacologia , Proteína Quinase C/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Ratos Sprague-Dawley , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/metabolismo , ômega-Conotoxinas/farmacologia
13.
Eur J Pharmacol ; 864: 172725, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31604070

RESUMO

Dehydrocorydaline, is an active alkaloid compound in Corydalis yanhusuo W. T. Wang. We found dehydrocorydaline induced antidepressant-like effects in a chronic unpredictable mild stress mouse model, but the exact mechanisms have not been addressed. We speculated that dehydrocorydaline may have an antidepressant effect via inhibiting monoamine transporters in the brain. We evaluated the mechanism of action of dehydrocorydaline by examining the levels of monoamine transmitters (5-HT, NE and DA) in the prefrontal cortex in chronic unpredictable mild stress mice. Then, we used cell models and the mouse synaptosome to study molecular and cellular mechanisms underlying these behaviors and monoamine alterations by dehydrocorydaline. Our results indicated that dehydrocorydaline affects the concentrations of monoamine transmitters and decreases the turnover ratio, which indicates increased neuronal activity. The possible mechanism is that dehydrocorydaline potently inhibits uptake-2 transporters with the IC50 values of 0.1-4 µM and could inhibit the reuptake of 5-HT/DA/NE in the synaptosome. These data suggest that dehydrocorydaline has an antidepressant effect that is likely related to changing the content of monoamines in the brain by inhibiting uptake-2 transporters.


Assuntos
Alcaloides/farmacologia , Antidepressivos/farmacologia , Proteínas de Membrana Transportadoras/metabolismo , Estresse Psicológico/tratamento farmacológico , Estresse Psicológico/metabolismo , Alcaloides/uso terapêutico , Animais , Antidepressivos/uso terapêutico , Comportamento Animal/efeitos dos fármacos , Monoaminas Biogênicas/metabolismo , Transporte Biológico/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Encéfalo/patologia , Doença Crônica , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Masculino , Camundongos , Camundongos Endogâmicos ICR , Estresse Psicológico/patologia , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/metabolismo
14.
Neurochem Res ; 44(10): 2435-2447, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31535355

RESUMO

Vinpocetine is considered as neuroprotectant drug and used for treatment of brain ischemia and cognitive deficiencies for decades. A number of enzymes, channels and receptors can bind vinpocetine, however the mechanisms of many effects' are still not clear. The present study investigated the effects of vinpocetine from the mitochondrial bioenergetic aspects. In primary brain capillary endothelial cells the purinergic receptor-stimulated mitochondrial Ca2+ uptake and efflux were studied. Vinpocetine exerted a partial inhibition on the mitochondrial calcium efflux. In rodent brain synaptosomes vinpocetine (30 µM) inhibited respiration in uncoupler stimulated synaptosomes and decreased H2O2 release from the nerve terminals in resting and in complex I inhibited conditions, respectively. In isolated rat brain mitochondria using either complex I or complex II substrates leak respiration was stimulated, but ADP-induced respiration was inhibited by vinpocetine. The stimulation of oxidation was associated with a small extent of membrane depolarization. Mitochondrial H2O2 production was inhibited by vinpocetine under all conditions investigated. The most pronounced effects were detected with the complex II substrate succinate. Vinpocetine also mitigated both Ca2+-induced mitochondrial Ca2+-release and Ca2+-induced mitochondrial swelling. It lowered the rate of mitochondrial ATP synthesis, while increasing ATPase activity. These results indicate more than a single mitochondrial target of this vinca alkaloid. The relevance of the affected mitochondrial mechanisms in the anti ischemic effect of vinpocetine is discussed.


Assuntos
Encéfalo/efeitos dos fármacos , Células Endoteliais/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Sinaptossomos/efeitos dos fármacos , Alcaloides de Vinca/farmacologia , Animais , Encéfalo/metabolismo , Cálcio/metabolismo , Células Endoteliais/metabolismo , Peróxido de Hidrogênio/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Fármacos Neuroprotetores/farmacologia , Ratos Wistar , Sinaptossomos/metabolismo
15.
Neurosci Lett ; 712: 134474, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31479724

RESUMO

Extracellular adenine nucleotides and nucleosides, such as adenosine-5'-triphosphate (ATP) and adenosine, are among least investigated signaling factors that participate in 17ß-estradiol (E2)-mediated synaptic rearrangements in rodent hippocampus. Their levels in the extrasynaptic space are tightly controlled by ecto-nucleoside triphosphate diphosphohydrolases1-3 (NTPDase1-3)/ecto-5'-nucleotidase (eN) enzyme chain. Therefore, the aim of the present study was to get closer insight in the E2-induced decrease in NTPDase and eN activity in the hippocampal synaptic compartment of male rats and to identify estradiol receptors (ERs i.e. ERα, ERß or GPER1) responsible for the observed effects of E2. In this study we show indiscriminate participation of estradiol receptor α (ERα), -ß (ERß) and G- protein coupled estrogen receptor 1 (GPER1) in the mediation of E2 actions in hippocampal synaptosomes of male rats. Synaptic NTPDase1-3 activities are modulated only through activation of ERß, while activation of ERα, -ß and/or non-classical GPER1 decreases synaptic eN activity. Since both ATP and adenosine function as neuromodulators in the hippocampal networks, influencing its function, profound knowledge of mechanisms by which ectonucleotidases are regulated/modulated is of great importance.


Assuntos
Adenosina Trifosfatases/metabolismo , Antígenos CD/metabolismo , Apirase/metabolismo , Receptor alfa de Estrogênio/metabolismo , Receptor beta de Estrogênio/metabolismo , Hipocampo/metabolismo , Pirofosfatases/metabolismo , Sinaptossomos/metabolismo , Animais , Estradiol/análogos & derivados , Estradiol/farmacologia , Receptor alfa de Estrogênio/agonistas , Receptor beta de Estrogênio/agonistas , Fulvestranto/farmacologia , Ginsenosídeos/farmacologia , Masculino , Nitrilos/farmacologia , Ratos , Sapogeninas/farmacologia , Sinaptossomos/efeitos dos fármacos
16.
J Pharmacol Exp Ther ; 371(2): 526-543, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31413138

RESUMO

Despite escalating methamphetamine use and high relapse rates, pharmacotherapeutics for methamphetamine use disorders are not available. Our iterative drug discovery program had found that R-N-(1,2-dihydroxypropyl)-2,6-cis-di-(4-methoxyphenethyl)piperidine hydrochloride (GZ-793A), a selective vesicular monoamine transporter-2 (VMAT2) inhibitor, specifically decreased methamphetamine's behavioral effects. However, GZ-793A inhibited human-ether-a-go-go-related gene (hERG) channels, suggesting cardiotoxicity and prohibiting clinical development. The current study determined if replacement of GZ-793A's piperidine ring with a phenylalkyl group to yield S-3-(4-methoxyphenyl)-N-(1-phenylpropan-2-yl)propan-1-amine (GZ-11608) diminished hERG interaction while retaining pharmacological efficacy. VMAT2 inhibition, target selectivity, and mechanism of GZ-11608-induced inhibition of methamphetamine-evoked vesicular dopamine release were determined. We used GZ-11608 doses that decreased methamphetamine-sensitized activity to evaluate the potential exacerbation of methamphetamine-induced dopaminergic neurotoxicity. GZ-11608-induced decreases in methamphetamine reinforcement and abuse liability were determined using self-administration, reinstatement, and substitution assays. Results show that GZ-11608 exhibited high affinity (Ki = 25 nM) and selectivity (92-1180-fold) for VMAT2 over nicotinic receptors, dopamine transporter, and hERG, suggesting low side-effects. GZ-11608 (EC50 = 620 nM) released vesicular dopamine 25-fold less potently than it inhibited VMAT2 dopamine uptake. GZ-11608 competitively inhibited methamphetamine-evoked vesicular dopamine release (Schild regression slope = 0.9 ± 0.13). GZ-11608 decreased methamphetamine sensitization without altering striatal dopamine content or exacerbating methamphetamine-induced dopamine depletion, revealing efficacy without neurotoxicity. GZ-11608 exhibited linear pharmacokinetics and rapid brain penetration. GZ-11608 decreased methamphetamine self-administration, and this effect was not surmounted by increasing methamphetamine unit doses. GZ-11608 reduced cue- and methamphetamine-induced reinstatement, suggesting potential to prevent relapse. GZ-11608 neither served as a reinforcer nor substituted for methamphetamine, suggesting low abuse liability. Thus, GZ-11608, a potent and selective VMAT2 inhibitor, shows promise as a therapeutic for methamphetamine use disorder. SIGNIFICANCE STATEMENT: GZ-11608 is a potent and selective vesicular monoamine transporter-2 inhibitor that decreases methamphetamine-induced dopamine release from isolated synaptic vesicles from brain dopaminergic neurons. Results from behavioral studies show that GZ-11608 specifically decreases methamphetamine-sensitized locomotor activity, methamphetamine self-administration, and reinstatement of methamphetamine-seeking behavior, without exhibiting abuse liability. Tolerance does not develop to the efficacy of GZ-11608 to decrease the behavioral effects of methamphetamine. In conclusion, GZ-11608 is an outstanding lead in our search for a therapeutic to treat methamphetamine use disorder.


Assuntos
Comportamento Aditivo/tratamento farmacológico , Encéfalo/efeitos dos fármacos , Inibidores da Captação de Dopamina/administração & dosagem , Locomoção/efeitos dos fármacos , Metanfetamina/administração & dosagem , Proteínas Vesiculares de Transporte de Monoamina/antagonistas & inibidores , Animais , Comportamento Aditivo/metabolismo , Comportamento Aditivo/psicologia , Encéfalo/metabolismo , Dopamina/metabolismo , Relação Dose-Resposta a Droga , Locomoção/fisiologia , Masculino , Ratos , Ratos Sprague-Dawley , Autoadministração , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/metabolismo , Proteínas Vesiculares de Transporte de Monoamina/metabolismo
17.
Neurochem Res ; 44(8): 2020-2029, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31264110

RESUMO

The neurotoxic effects of aluminum are generally associated with reduced antioxidant capacity, increased oxidative stress and apoptosis, which lead to the induction of neurodegenerative processes. Curcumin has a lipophilic polyphenol character and effects of antioxidant and anti-apoptotic. The present study was undertaken to examine possible aluminum exposure in rats brain synaptosomes and to investigate whether protective and therapeutic effects of curcumin on biochemical and morphological changes in both pre- and post-treated groups. Aluminum chloride (AlCl3) at 50 µM concentration and curcumin at 5 and 10 µg/mL doses were applied to hippocampal synaptosomes of rats according to experimental design. Biochemical effects were evaluated by MTT cytotoxicity, malondialdehyde (MDA) levels, nitric oxide (NO) levels, glutathione (GSH) levels, caspase 3 activities, cytochrome c levels, DNA fragmentation values and protein levels. Morphological examinations were done by TEM analysis. AlCI3 exposure in the synaptosomes enhanced oxidative stress, triggered apoptosis and caused ultrastructural alterations which were well reflected in the TEM images. Curcumin pre-treatment slightly ameliorated the MDA levels, NO levels, cytochrome c levels and caspase 3 activities in AlCI3-exposed synaptosomes, but these results were not statistically significant. Furthermore, curcumin post-treatment significantly improved oxidative damage and morphological alterations, and suppressed cytochrome c and caspase 3 activities. Taken together, our data showed that curcumin had more therapeutic effects than protective effects in AlCI3-induced neurotoxicity. Nevertheless, the therapeutic (post-protective) effects of curcumin should be further investigated in in vivo neurodegenerative models involving behavioral tests.


Assuntos
Alumínio/efeitos adversos , Curcumina/uso terapêutico , Hipocampo/efeitos dos fármacos , Síndromes Neurotóxicas/tratamento farmacológico , Sinaptossomos/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Caspase 3/metabolismo , Citocromos c/metabolismo , Fragmentação do DNA/efeitos dos fármacos , Glutationa/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Malondialdeído/metabolismo , Fármacos Neuroprotetores/uso terapêutico , Síndromes Neurotóxicas/prevenção & controle , Óxido Nítrico/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Ratos Wistar
18.
Toxicol In Vitro ; 60: 389-399, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31195087

RESUMO

A well-known cationic biocide of guanidine polymer family, polyhexamethylene guanidine hydrochloride (PHMG) has been tested against smooth muscle cells isolated from swine myometrium, synaptosomes of rat brain nerve terminals and rat blood platelets for the membrane action. It was established that PHMG blocked the activity of Na+,K+-ATPase of smooth muscle cells plasma membrane by 82.2 ±â€¯0.9% at a concentration of 7 ppm, whilst a dose-dependent depolarization of synaptosomes and platelets became appreciable at 100-500 ppm. Comparative studies by the methods of mass spectrometry (MALDI-TOF and PDMS-TOF), viscosimetry, dynamic light scattering and model phospholipid membranes revealed PHMG oligomers with various number of repeat units (8-16) that formed K+-selective potential-dependent pores in sterol-free phosphatidylethanolamine-containing phospholipid bilayers at a concentration of 1 ppm. Obtained results suggest that besides acidic lipids and membrane proteins phosphatidylethanolamine and cholesterol are the other major factors responsible for the differences between PHMG-induced plasma membrane depolarization of microbial and eukaryotic cells and thus, diverse modes of PHMG membrane action.


Assuntos
Plaquetas/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Desinfetantes/toxicidade , Guanidinas/toxicidade , Miócitos de Músculo Liso/efeitos dos fármacos , Sinaptossomos/efeitos dos fármacos , Animais , Bicamadas Lipídicas/metabolismo , Masculino , Fosfolipídeos/metabolismo , Porosidade , Ratos Wistar
19.
ACS Chem Neurosci ; 10(8): 3718-3730, 2019 08 21.
Artigo em Inglês | MEDLINE | ID: mdl-31184115

RESUMO

The dopamine transporter (DAT) serves a pivotal role in controlling dopamine (DA)-mediated neurotransmission by clearing DA from synaptic and perisynaptic spaces and controlling its action at postsynaptic DA receptors. Major drugs of abuse such as amphetamine and cocaine interact with DAT to mediate their effects by enhancing extracellular DA concentrations. We previously identified a novel allosteric site in the related human serotonin transporter that lies outside the central substrate and inhibitor binding pocket. We used the hybrid structure based (HSB) method to screen for allosteric modulator molecules that target a similar site in DAT. We identified a compound, KM822, that was found to be a selective, noncompetitive inhibitor of DAT. We confirmed the structural determinants of KM822 allosteric binding within the allosteric site by structure/function and substituted cysteine scanning accessibility biotinylation experiments. In the in vitro cell-based assay and ex vivo in both rat striatal synaptosomal and slice preparations, KM822 was found to decrease the affinity of cocaine for DAT. The in vivo effects of KM822 on cocaine were tested on psychostimulant-associated behaviors in a planarian model where KM822 specifically inhibited the locomotion elicited by DAT-interacting stimulants amphetamine and cocaine. Overall, KM822 provides a unique opportunity as a molecular probe to examine allosteric modulation of DAT function.


Assuntos
Regulação Alostérica/efeitos dos fármacos , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismo , Dopamina/metabolismo , Sinaptossomos/efeitos dos fármacos , Animais , Cocaína/farmacologia , Corpo Estriado/efeitos dos fármacos , Corpo Estriado/metabolismo , Inibidores da Captação de Dopamina/farmacologia , Humanos , Masculino , Atividade Motora/efeitos dos fármacos , Planárias , Ratos , Ratos Sprague-Dawley , Sinaptossomos/metabolismo
20.
Sci Rep ; 9(1): 8228, 2019 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-31160730

RESUMO

Traumatic brain injury (TBI) is a risk factor for Alzheimer's disease (AD), although the mechanisms contributing to this increased risk are unknown. Insulin resistance is an additional risk factor for AD whereby decreased insulin signaling increases synaptic sensitivity to amyloid beta (Aß) and tau. Considering this, we used rats that underwent a lateral fluid percussion injury at acute and chronic time-points to investigate whether decreased insulin responsiveness in TBI animals is playing a role in synaptic vulnerability to AD pathology. We detected acute and chronic decreases in insulin responsiveness in isolated hippocampal synaptosomes after TBI. In addition to assessing both Aß and tau binding on synaptosomes, we performed electrophysiology to assess the dysfunctional impact of Aß and tau oligomers as well as the protective effect of insulin. While we saw no difference in binding or degree of LTP inhibition by either Aß or tau oligomers between sham and TBI animals, we found that insulin treatment was able to block oligomer-induced LTP inhibition in sham but not in TBI animals. Since insulin treatment has been discussed as a therapy for AD, this gives valuable insight into therapeutic implications of treating AD patients based on one's history of associated risk factors.


Assuntos
Peptídeos beta-Amiloides/toxicidade , Lesões Encefálicas Traumáticas/fisiopatologia , Resistência à Insulina , Insulina/metabolismo , Multimerização Proteica , Sinapses/patologia , Proteínas tau/toxicidade , Animais , Lesões Encefálicas Traumáticas/patologia , Hipocampo/patologia , Hipocampo/fisiopatologia , Humanos , Potenciação de Longa Duração/efeitos dos fármacos , Masculino , Ratos Sprague-Dawley , Proteína 3 Supressora da Sinalização de Citocinas/metabolismo , Sinapses/efeitos dos fármacos , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA