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1.
Life Sci ; 240: 117068, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31751583

RESUMO

AIMS: Bradycardia contributes to tachy-brady arrhythmias or sinus arrest during heart failure (HF). Sinoatrial node (SAN) adenosine A1 receptors (ADO A1Rs) are upregulated in HF, and adenosine is known to exert negative chronotropic effects on the SAN. Here, we investigated the role of A1R signaling at physiologically relevant ADO concentrations on HF SAN pacemaker cells. MAIN METHODS: Dogs with tachypacing-induced chronic HF and normal controls (CTL) were studied. SAN tissue was collected for A1R and GIRK mRNA quantification. SAN cells were isolated for perforated patch clamp recordings and firing rate (bpm), slope of slow diastolic depolarization (SDD), and maximum diastolic potential (MDP) were measured. Action potentials (APs) and currents were recorded before and after addition of 1 and 10 µM ADO. To assess contributions of A1R and G protein-coupled Inward Rectifier Potassium Current (GIRK) to ADO effects, APs were measured after the addition of DPCPX (selective A1R antagonist) or TPQ (selective GIRK blocker). KEY FINDINGS: A1R and GIRK mRNA expression were significantly increased in HF. In addition, ADO induced greater rate slowing and membrane hyperpolarization in HF vs CTL (p < 0.05). DPCPX prevented ADO-induced rate slowing in CTL and HF cells. The ADO-induced inward rectifying current, IKado, was observed significantly more frequently in HF than in CTL. TPQ prevented ADO-induced rate slowing in HF. SIGNIFICANCE: An increase in A1R and GIRK expression enhances IKAdo, causing hyperpolarization, and subsequent negative chronotropic effects in canine chronic HF at relevant [ADO]. GIRK blockade may be a useful strategy to mitigate bradycardia in HF.


Assuntos
Agonistas do Receptor A1 de Adenosina/farmacologia , Adenosina/farmacologia , Canais de Potássio Corretores do Fluxo de Internalização Acoplados a Proteínas G/agonistas , Insuficiência Cardíaca/fisiopatologia , Frequência Cardíaca/efeitos dos fármacos , Receptor A1 de Adenosina/metabolismo , Nó Sinoatrial/citologia , Nó Sinoatrial/efeitos dos fármacos , Potenciais de Ação/efeitos dos fármacos , Antagonistas do Receptor A1 de Adenosina/farmacologia , Animais , Venenos de Abelha/farmacologia , Relógios Biológicos , Doença Crônica , Cães , Feminino , Canais de Potássio Corretores do Fluxo de Internalização Acoplados a Proteínas G/antagonistas & inibidores , Canais de Potássio Corretores do Fluxo de Internalização Acoplados a Proteínas G/efeitos dos fármacos , Técnicas In Vitro , Masculino , Técnicas de Patch-Clamp , Bloqueadores dos Canais de Potássio/farmacologia , Receptor A1 de Adenosina/efeitos dos fármacos , Xantinas/farmacologia
2.
Molecules ; 24(11)2019 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-31181839

RESUMO

8-Arylethynylxanthine derivatives are potent, selective adenosine A2A receptor antagonists, which represent (potential) therapeutics for Parkinson's disease, Alzheimer's dementia, and the immunotherapy of cancer. 6-Amino-5-amidouracil derivatives are important precursors for the synthesis of such xanthines. We noticed an unexpected duplication of NMR signals in many of these uracil derivatives. Here, we present a detailed analytical study of structurally diverse 6-amino-5-carboxamidouracils employing dynamic and two-dimensional NMR spectroscopy, density functional theory calculations, and X-ray analysis to explain the unexpected properties of these valuable drug intermediates.


Assuntos
Amidas/química , Conformação Molecular , Uracila/análogos & derivados , Xantinas/farmacologia , Antagonistas do Receptor A2 de Adenosina/síntese química , Antagonistas do Receptor A2 de Adenosina/química , Espectroscopia de Prótons por Ressonância Magnética , Uracila/química
3.
J Pharmacol Exp Ther ; 370(3): 350-359, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31201216

RESUMO

Glucose-stimulated insulin secretion from pancreatic ß-cells is controlled by ATP-regulated potassium (KATP) channels composed of Kir6.2 and sulfonylurea receptor 1 (SUR1) subunits. The KATP channel-opener diazoxide is FDA-approved for treating hyperinsulinism and hypoglycemia but suffers from off-target effects on vascular KATP channels and other ion channels. The development of more specific openers would provide critically needed tool compounds for probing the therapeutic potential of Kir6.2/SUR1 activation. Here, we characterize a novel scaffold activator of Kir6.2/SUR1 that our group recently discovered in a high-throughput screen. Optimization efforts with medicinal chemistry identified key structural elements that are essential for VU0071063-dependent opening of Kir6.2/SUR1. VU0071063 has no effects on heterologously expressed Kir6.1/SUR2B channels or ductus arteriole tone, indicating it does not open vascular KATP channels. VU0071063 induces hyperpolarization of ß-cell membrane potential and inhibits insulin secretion more potently than diazoxide. VU0071063 exhibits metabolic and pharmacokinetic properties that are favorable for an in vivo probe and is brain penetrant. Administration of VU0071063 inhibits glucose-stimulated insulin secretion and glucose-lowering in mice. Taken together, these studies indicate that VU0071063 is a more potent and specific opener of Kir6.2/SUR1 than diazoxide and should be useful as an in vitro and in vivo tool compound for investigating the therapeutic potential of Kir6.2/SUR1 expressed in the pancreas and brain.


Assuntos
Ativação do Canal Iônico/efeitos dos fármacos , Canais de Potássio Corretores do Fluxo de Internalização/metabolismo , Receptores Sulfonilureia/metabolismo , Xantinas/farmacologia , Xantinas/farmacocinética , Animais , Canal Arterial/efeitos dos fármacos , Canal Arterial/fisiologia , Glucose/farmacologia , Células HEK293 , Humanos , Secreção de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/metabolismo , Camundongos , Relação Estrutura-Atividade , Vasodilatação/efeitos dos fármacos , Xantinas/química
4.
Pharmacol Rep ; 71(4): 676-681, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31200233

RESUMO

BACKGROUND: Adenosine, an endogenous nucleoside, modulates the release of monoamines, e.g., noradrenaline, serotonin, and dopamine in the brain. Both nonselective and selective stimulation of adenosine receptors produce symptoms of depression in some animal models. Therefore, the main objective of our study was to assess the influence of a selective adenosine A1 receptor antagonist (DPCPX) and a selective adenosine A2A receptor antagonist (DMPX) on the activity of agomelatine and tianeptine. METHODS: The forced swim test (FST) and tail suspension test (TST) were performed to assess the effects of DPCPX and DMPX on the antidepressant-like activity of agomelatine and tianeptine. Drug serum and brain levels were analyzed using HPLC. RESULTS: Co-administration of agomelatine (20 mg/kg) or tianeptine (15 mg/kg) with DMPX (3 mg/kg), but not with DPCPX (1 mg/kg), significantly reduced the immobility time both in the FST and TST in mice. These effects were not associated with an enhancement in animals' spontaneous locomotor activity. The observed changes in the mouse behavior after concomitant injection of DMPX and the tested antidepressant agents were associated with elevated brain concentration of agomelatine and tianeptine. CONCLUSION: Our study shows a synergistic action of the selective A2A receptor antagonist and the studied antidepressant drugs, and a lack of such interaction in the case of the selective A1 receptor antagonist. The interaction between DMPX and agomelatine/tianeptine at least partly occurs in the pharmacokinetic phase. A combination of a selective A2A receptor antagonist and an antidepressant may be a new strategy for treating depression.


Assuntos
Acetamidas/farmacologia , Antagonistas do Receptor A2 de Adenosina/farmacologia , Antidepressivos/farmacologia , Depressão/tratamento farmacológico , Teobromina/análogos & derivados , Tiazepinas/farmacologia , Acetamidas/farmacocinética , Antagonistas do Receptor A1 de Adenosina/farmacocinética , Antagonistas do Receptor A1 de Adenosina/farmacologia , Antagonistas do Receptor A2 de Adenosina/farmacocinética , Animais , Antidepressivos/farmacocinética , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Depressão/sangue , Depressão/metabolismo , Sinergismo Farmacológico , Masculino , Camundongos , Atividade Motora/efeitos dos fármacos , Natação , Teobromina/farmacocinética , Teobromina/farmacologia , Tiazepinas/farmacocinética , Xantinas/farmacocinética , Xantinas/farmacologia
5.
Molecules ; 24(12)2019 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-31212849

RESUMO

In earlier studies, we generated concentration-response (E/c) curves with CPA (N6-cyclopentyladenosine; a selective A1 adenosine receptor agonist) or adenosine, in the presence or absence of S-(2-hydroxy-5-nitrobenzyl)-6-thioinosine (NBTI, a selective nucleoside transport inhibitor), and with or without a pretreatment with 8-cyclopentyl-N3-[3-(4-(fluorosulfonyl)-benzoyloxy)propyl]-N1-propylxanthine (FSCPX, a chemical known as a selective, irreversible A1 adenosine receptor antagonist), in isolated, paced guinea pig left atria. Meanwhile, we observed a paradoxical phenomenon, i.e. the co-treatment with FSCPX and NBTI appeared to enhance the direct negative inotropic response to adenosine. In the present in silico study, we aimed to reproduce eight of these E/c curves. Four models (and two additional variants of the last model) were constructed, each one representing a set of assumptions, in order to find the model exhibiting the best fit to the ex vivo data, and to gain insight into the paradoxical phenomenon in question. We have obtained in silico evidence for an interference between effects of FSCPX and NBTI upon our ex vivo experimental setting. Regarding the mechanism of this interference, in silico evidence has been gained for the assumption that FSCPX inhibits the effect of NBTI on the level of endogenous (but not exogenous) adenosine. As an explanation, it may be hypothesized that FSCPX inhibits an enzyme participating in the interstitial adenosine formation. In addition, our results suggest that NBTI does not stop the inward adenosine flux in the guinea pig atrium completely.


Assuntos
Antagonistas do Receptor A1 de Adenosina/química , Proteínas de Transporte de Nucleobases/química , Receptor A1 de Adenosina/química , Xantinas/química , Adenosina/química , Adenosina/farmacologia , Antagonistas do Receptor A1 de Adenosina/farmacologia , Animais , Relação Dose-Resposta a Droga , Cobaias , Proteínas de Transporte de Nucleobases/antagonistas & inibidores , Xantinas/farmacologia
6.
Eur J Med Chem ; 176: 117-128, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31108261

RESUMO

A series of novel xanthine/NO donor hybrids containing 1,3,8-trisubstituted or 1,8-disubstituted xanthine derivatives were designed and synthesized. The synthesized compounds were tested in a cell viability assay using human mammary gland epithelial cell line (MCF-10A) where all the compounds exhibited no cytotoxic effects and more than 90% cell viability at a concentration of 50 µM. The oxime containing compounds 7a-b and 17-24 were more active as antiproliferative agents than their non-oxime congeners 6a-b and 9-16. Hydroxyimino-phenethyl scaffold compounds 17-24 were more active than the hydroxyimino-ethyl phenyl acetamide 7a-b derivatives. Compounds 18-20 and 22-24 exhibited inhibition of EGFR with IC50 ranging from 0.32 to 2.88 µM. Compounds 18-20 and 22-24 increased the level of active caspase 3 by 4-8 folds, compared to the control cells in Panc-1 cell lines compared to doxorubicin as a reference drug. Compounds 18, 22 and 23 were the most caspase-3 inducers. Compounds 22 and 23 increased the levels of caspase-8 and 9 indicating activation of both intrinsic and extrinsic pathways and showed potent induction of Bax, down-regulation of Bcl-2 protein levels and over-expression of cytochrome c levels in Panc-1 human pancreas cancer cells. Compound 23 exhibited mainly cell cycle arrest at the Pre-G1 and G2/M phases in the cell cycle analysis of Panc-1 cell line. The drug likeness profiles of compounds 18-20 and 22-24 were predicted to have good to excellent drug likeness profiles specially compounds 18-20 and 23. Finally molecular docking study was performed at the EGFR active site to suggest thier possible binding mode. The hydroxyimino-phenethyl scaffold compounds 17-24 represent an interesting starting point to optimize their pharmacokinetics and pharmacodynamics profiles.


Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Oximas/farmacologia , Xantinas/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Antineoplásicos/toxicidade , Caspase 3/metabolismo , Caspase 8/metabolismo , Caspase 9/metabolismo , Domínio Catalítico , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Citocromos c/metabolismo , Ensaios de Seleção de Medicamentos Antitumorais , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/química , Pontos de Checagem da Fase G1 do Ciclo Celular/efeitos dos fármacos , Humanos , Simulação de Acoplamento Molecular , Estrutura Molecular , Oximas/síntese química , Oximas/química , Oximas/toxicidade , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Relação Estrutura-Atividade , Xantinas/síntese química , Xantinas/química , Xantinas/toxicidade , Proteína X Associada a bcl-2/metabolismo
7.
Molecules ; 24(7)2019 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-30965668

RESUMO

To test whether KMUP-1 (7-[2-[4-(2-chlorophenyl) piperazinyl]ethyl]-1,3-dimethylxanthine) prevents myocardial ischemia-induced apoptosis, we examined KMUP-1-treated H9c2 cells culture. Recent attention has focused on the activation of nitric oxide (NO)-guanosine 3', 5'cyclic monophosphate (cGMP)-protein kinase G (PKG) signaling pathway triggered by mitogen-activated protein kinase (MAPK) family, including extracellular-signal regulated kinase 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK), and p38 in the mechanism of cardiac protection during ischemia-induced cell-death. We propose that KMUP-1 inhibits ischemia-induced apoptosis in H9c2 cells culture through these pathways. Cell viability was assessed using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and apoptotic evaluation was conducted using DNA ladder assay and Hoechst 33342 staining. The level of intracellular calcium was detected using - Fura2-acetoxymethyl (Fura2-AM) staining, and mitochondrial calcium with Rhod 2-acetoxymethyl (Rhod 2-AM) staining under fluorescence microscopic observation. The expression of endothelium NO synthase (eNOS), inducible NO synthase (iNOS), soluble guanylate cyclase α1 (sGCα1), PKG, Bcl-2/Bax ratio, ERK1/2, p38, and JNK proteins were measured by Western blotting assay. KMUP-1 pretreatment improved cell viability and inhibited ischemia-induced apoptosis of H9c2 cells. Calcium overload both in the intracellular and mitochondrial sites was attenuated by KMUP-1 pretreatment. Moreover, KMUP-1 reduced intracellular reactive oxygen species (ROS), increased plasma NOx (nitrite and nitrate) level, and the expression of eNOS. Otherwise, the iNOS expression was downregulated. KMUP-1 pretreatment upregulated the expression of sGCα1 and PKG protein. The ratio of Bcl-2/Bax expression was increased by the elevated level of Bcl2 and decreased level of Bax. In comparison with the ischemia group, KMUP-1 pretreatment groups reduced the expression of phosphorylated extracellular signal-regulated kinases ERK1/2, p-p38, and p-JNK as well. Therefore, KMUP-1 inhibits myocardial ischemia-induced apoptosis by restoration of cellular calcium influx through the mechanism of NO-cGMP-MAPK pathways.


Assuntos
Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Isquemia Miocárdica/metabolismo , Miócitos Cardíacos/citologia , Piperidinas/farmacologia , Xantinas/farmacologia , Animais , Apoptose/efeitos dos fármacos , Cálcio/metabolismo , Linhagem Celular , GMP Cíclico/metabolismo , Mitocôndrias/metabolismo , Modelos Biológicos , Isquemia Miocárdica/tratamento farmacológico , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Óxido Nítrico/metabolismo , Ratos
8.
PLoS Negl Trop Dis ; 13(2): e0007153, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30730880

RESUMO

BACKGROUND: Tick feeding causes extreme morbidity and mortality to humans through transmission of pathogens and causes severe economic losses to the agricultural industry by reducing livestock yield. Salivary gland secretions are essential for tick feeding and thus, reducing or preventing saliva secretions into the vertebrate host is likely to reduce feeding and hinder pathogen life cycles. Unfortunately, the membrane physiology of tick salivary glands is underexplored and this gap in knowledge limits the development of novel therapeutics for inducing cessation of tick feeding. METHODOLOGY: We studied the influence of inward rectifier potassium (Kir) channel subtypes to the functional capacity of the isolated tick salivary gland through the use of a modified Ramsay assay. The secreted saliva was subsequently used for quantification of the elemental composition of the secreted saliva after the glands were exposed to K+ channel modulators as a measure of osmoregulatory capacity. Lastly, changes to blood feeding behavior and mortality were measured with the use of a membrane feeding system. PRINCIPAL FINDINGS: In this study, we characterized the fundamental role of Kir channel subtypes in tick salivary gland function and provide evidence that pharmacological inhibition of these ion channels reduces the secretory activity of the Amblyomma americanum salivary gland. The reduced secretory capacity of the salivary gland was directly correlated with a dramatic reduction of blood ingestion during feeding. Further, exposure to small-molecule modulators of Kir channel subtypes induced mortality to ticks that is likely resultant from an altered osmoregulatory capacity. CONCLUSIONS: Our data contribute to understanding of tick salivary gland function and could guide future campaigns aiming to develop chemical or reverse vaccinology technologies to reduce the worldwide burden of tick feeding and tick-vectored pathogens.


Assuntos
Ixodidae/fisiologia , Canais de Potássio Corretores do Fluxo de Internalização/metabolismo , Animais , Comportamento Alimentar/fisiologia , Ixodidae/efeitos dos fármacos , Moduladores de Transporte de Membrana/farmacologia , Pinacidil/farmacologia , Canais de Potássio Corretores do Fluxo de Internalização/genética , Glândulas Salivares/fisiologia , Xantinas/farmacologia
9.
Neurosci Lett ; 699: 47-53, 2019 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-30703410

RESUMO

The extracellular signal-regulated kinase (ERK) is enriched in the central nervous system, including the dopamine responsive regions such as the striatum and medial prefrontal cortex (mPFC). The kinase is sensitive to changing cellular and synaptic input and is implicated in the regulation of synaptic transmission and plasticity. In this study, the role of a Gαi/o protein-coupled adenosine A1 receptor in the regulation of ERK1/2 was investigated in the rat brain in vivo. We found that an A1 agonist CPA after an intraperitoneal injection reduced ERK1/2 phosphorylation in the nucleus accumbens (NAc) and mPFC. In contrast, a single dose of an A1 antagonist DPCPX induced a rapid and transient increase in ERK1/2 phosphorylation in the caudate putamen (CPu), NAc, and mPFC. Pretreatment with a dopamine D1 receptor antagonist SCH23390 abolished the DPCPX-induced ERK1/2 phosphorylation in the striatum and mPFC. Coadministration of DPCPX and a D1 agonist SKF81297 at a low dose induced a greater elevation of ERK1/2 phosphorylation. Activation or blockade of A1 receptors had no effect on total ERK1/2 expression in the striatum and mPFC. These results reveal an existence of an inhibitory linkage from adenosine A1 receptors to ERK1/2 in striatal and mPFC neurons. This inhibitory linkage seems to form a dynamic balance with positive dopamine D1 receptor signaling to control the ERK1/2 pathway.


Assuntos
Agonistas do Receptor A1 de Adenosina/farmacologia , Antagonistas do Receptor A1 de Adenosina/farmacologia , Corpo Estriado/efeitos dos fármacos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Córtex Pré-Frontal/efeitos dos fármacos , Receptor A1 de Adenosina/metabolismo , Adenosina/análogos & derivados , Adenosina/farmacologia , Animais , Benzazepinas/farmacologia , Corpo Estriado/enzimologia , Sinergismo Farmacológico , Masculino , Núcleo Accumbens/metabolismo , Fosforilação/efeitos dos fármacos , Córtex Pré-Frontal/enzimologia , Ratos , Xantinas/antagonistas & inibidores , Xantinas/farmacologia
10.
Neurobiol Learn Mem ; 160: 91-97, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-29614375

RESUMO

Sleep deprivation is known to affect memory formation, but how it interacts with different memory systems is not completely understood. Adenosine, a homeostatic regulator of sleep that has an increased extracellular concentration during sleep deprivation, is one of the neuromodulators that may be involved in this interaction. The A1 adenosine receptor is involved in both sleep regulation and memory formation. Among other pathways, the A1 receptor decreases cAMP levels in the cytosol and thus also regulates protein kinase A (PKA) and exchange protein activated by cAMP (EPAC) activity. To verify the role of the A1 receptor in the memory impairment caused by sleep deprivation, we tested the effect of 96 h of sleep deprivation (SD) and the administration of DPCPX, an A1 receptor antagonist on male Wistar rats prior to the training sessions for two memory tasks that relies on the hippocampal function: the multiple trial inhibitory avoidance (MTIA) task, which also requires the striatum, and the contextual fear conditioning (CFC) task, which does not. We also evaluated the effect of SD, DPCPX and the MTIA training session on the protein expression levels of the A1 receptor, PKA phosphorylation and EPAC activity in both the hippocampus and the striatum. Sleep deprivation impaired the performance in the test sessions of both tasks; DPCPX was able to prevent the impairment in the MTIA test but not in the CFC test. SD increased A1 receptor protein expression levels in the striatum but not in the hippocampus and also decreased PKA phosphorylation in both structures; DPCPX prevented this decrease in the striatum, but not in the hippocampus. Finally, SD had no effect on EPAC activity in either of the structures. These results indicate that the A1 adenosine receptors play a role in the memory impairment caused by sleep deprivation in tasks that involve the striatum through modulation of the cAMP/PKA pathway.


Assuntos
Adenosina/metabolismo , Aprendizagem da Esquiva/fisiologia , Condicionamento Clássico/fisiologia , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Hipocampo , Transtornos da Memória , Receptor A1 de Adenosina/metabolismo , Privação do Sono , Antagonistas do Receptor A1 de Adenosina/farmacologia , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Comportamento Animal/efeitos dos fármacos , Comportamento Animal/fisiologia , Condicionamento Clássico/efeitos dos fármacos , Regulação para Baixo , Hipocampo/efeitos dos fármacos , Hipocampo/metabolismo , Hipocampo/fisiopatologia , Masculino , Transtornos da Memória/metabolismo , Transtornos da Memória/fisiopatologia , Ratos , Ratos Wistar , Receptor A1 de Adenosina/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Privação do Sono/metabolismo , Privação do Sono/fisiopatologia , Xantinas/farmacologia
11.
Neuropharmacology ; 144: 9-18, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30326239

RESUMO

Recent studies have underscored the importance of the CA2 area in social memory formation. This area, a narrow transition zone between hippocampal CA3 and CA1 areas, is endowed with special connectivity and a distinctive molecular composition. In particular, adenosine A1 receptors (A1R) are enriched in CA2, and based on the prominent synaptic potentiation induced by A1R antagonists (e.g., caffeine) in this area, it has been proposed that CA2 is under the strong tonic control of A1R activation. It is unclear whether this special sensitivity of CA2 to A1R antagonists is due to an elevated extracellular concentration of adenosine or to a different A1R function. Here, using the recording of field potentials evoked simultaneously in CA2 and CA1 by Schaffer collateral stimulation, we confirm that the application of A1R antagonists, caffeine and DPCPX has a stronger effect on synaptic responses in CA2 than in those evoked in CA1. This difference was, at least partially, explained by the action of A1R antagonists on presynaptic A1Rs. We found that caffeine-induced potentiation in CA2 was restricted to Schaffer collateral synapses, but not to those formed by temporoammonic inputs. We also observed that the apparent affinity of an A1R agonist is similar for A1R in both CA2 and CA1 areas, which indicates that the tonic activation of A1R in both areas is comparable. Furthermore, we show that the direct activation of adenylyl cyclase with forskolin in the presence of rolipram, a phosphodiesterase inhibitor, greatly enhances the synaptic potentials in CA2 compared to CA1. The forskolin-induced potentiation was exacerbated in the presence of caffeine or DPCPX, accentuating the differences between the two areas. These results indicate that the tonic activation of A1Rs in area CA2 is not different to that of other hippocampal areas, but it is more efficiently coupled to the downstream effectors.


Assuntos
Região CA2 Hipocampal/efeitos dos fármacos , Antagonistas de Receptores Purinérgicos P1/farmacologia , Adenilil Ciclases/metabolismo , Animais , Região CA1 Hipocampal/efeitos dos fármacos , Região CA1 Hipocampal/metabolismo , Região CA2 Hipocampal/metabolismo , Cafeína/farmacologia , Colforsina/farmacologia , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Potenciais Pós-Sinápticos Excitadores/fisiologia , Masculino , Inibidores de Fosfodiesterase/farmacologia , Agonistas Purinérgicos/farmacologia , Ratos Sprague-Dawley , Receptor A1 de Adenosina/metabolismo , Rolipram/farmacologia , Sinapses/efeitos dos fármacos , Sinapses/metabolismo , Técnicas de Cultura de Tecidos , Xantinas/farmacologia
12.
Eur J Med Chem ; 162: 555-567, 2019 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-30472603

RESUMO

Histone lysine specific demethylase 1 (LSD1) has been recognized as an important epigenetic target for disease treatment. To date, a large number of LSD1 inhibitors have been developed, some of which are currently being evaluated in clinical trials for the treatment of cancers, virus infection, and neurodegenerative diseases. In this paper, we for the first time reported the ligand-based design of fragment-like xanthine derivatives as LSD1 inhibitors, of which compound 4 possessed acceptable pharmacological inhibition against LSD1 (IC50 = 6.45 µM) and favorable fragment-like nature, and therefore could be used as a promising template to design new LSD1 inhibitors. Interestingly, compounds 6c and 6i strongly suppressed growth of MGC-803 cells partly dependent on their LSD1 inhibition, and were also found to be able to inhibit BRD4 and IDO1. The docking studies were performed to rationalize the biochemical potency against LSD1 and to explain the observed activity discrepancy. The proof-of-concept work may provide an example for other natural ligand-based drug design.


Assuntos
Desenho de Drogas , Histona Desmetilases/antagonistas & inibidores , Ligantes , Xantinas/farmacologia , Proteínas de Ciclo Celular , Linhagem Celular , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Humanos , Indolamina-Pirrol 2,3,-Dioxigenase/antagonistas & inibidores , Simulação de Acoplamento Molecular , Proteínas Nucleares/antagonistas & inibidores , Fragmentos de Peptídeos/farmacologia , Relação Estrutura-Atividade , Fatores de Transcrição/antagonistas & inibidores , Xantinas/síntese química
13.
Artigo em Inglês | MEDLINE | ID: mdl-30213684

RESUMO

In general, preparations of coffee, teas, and cocoa containing high levels of polyphenols, L-theanine and other bioactive compounds selectively enhance mood and cognition effects of caffeine. This review summarizes the bioactive components of commonly consumed natural caffeine sources (e.g. guayusa, mate and camellia teas, coffee and cocoa) and analyzes the psychopharmacology of constituent phytochemicals: methylxanthines, polyphenols, and L-theanine. Acute and chronic synergistic effects of these compounds on mood and cognition are compared and discussed. Specific sets of constituent compounds such as polyphenols, theobromine and L-theanine appear to enhance mood and cognition effects of caffeine and alleviate negative psychophysiological effects of caffeine. However, more research is needed to identify optimal combinations and ratios of caffeine and phytochemicals for enhancement of cognitive performance.


Assuntos
Cafeína/farmacologia , Compostos Fitoquímicos/farmacologia , Psicotrópicos/farmacologia , Xantinas/farmacologia , Animais , Bebidas , Interações de Medicamentos , Humanos , Plantas/química
14.
Arq Neuropsiquiatr ; 76(11): 736-742, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30570016

RESUMO

OBJECTIVE: Neuropathic pain is a chronic pain condition caused by damage or dysfunction of the central or peripheral nervous system. Electroacupuncture (EA) has an antinociceptive effect on neuropathic pain, which is partially due to inhibiting astrocyte activation in the spinal cord. METHODS: We found that an intrathecal injection of 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), a selective adenosine A1 receptor antagonist, reversed the antinociceptive effects of EA in a chronic constriction injury-induced neuropathic pain model. RESULTS: The expression of GFAP in L4-L6 spinal cord was significantly upgraded, while DPCPX suppressed the effect of the EA-mediating inhibition of astrocyte activation, as well as wiping out the EA-induced suppression of cytokine content (TNF-α). CONCLUSIONS: These results indicated that the adenosine A1 receptor is involved in EA actions during neuropathic pain through suppressing astrocyte activation as well as TNF-α upregulation of EA, giving enlightenment to the mechanisms of acupuncture analgesia and development of therapeutic targets for neuropathic pain.


Assuntos
Astrócitos/metabolismo , Eletroacupuntura/métodos , Neuralgia/terapia , Receptor A1 de Adenosina/metabolismo , Medula Espinal/efeitos dos fármacos , Xantinas/farmacologia , Animais , Astrócitos/efeitos dos fármacos , Modelos Animais de Doenças , Injeções Espinhais , Masculino , Ratos , Ratos Sprague-Dawley , Receptor A1 de Adenosina/administração & dosagem , Nervo Isquiático/lesões , Medula Espinal/metabolismo , Xantinas/administração & dosagem
15.
Molecules ; 23(10)2018 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-30249030

RESUMO

Xanthine-based KMUP-1 was shown to inhibit phosphodiesterases (PDEs) and modulate G-protein coupled receptors (GPCRs) to lower hyperlipidemia and body weight. This study further investigated whether KMUP-1 affects adipogenesis and lipolysis in 3T3-L1 preadipocytes. KMUP-1 (1⁻40 µM) concentration-dependently attenuated Oil Red O (ORO) staining and decreased triglyceride (TG) accumulation, indicating adipogenesis inhibition in 3T3-L1 cells. In contrast, the ß-agonist ractopamine increased ORO staining and TG accumulation and adipogenesis. KMUP-1 (1⁻40 µM) also reduced MAPKs/Akt/PPARγ expression, PPARγ1/PPARγ2 mRNA, and p-ERK immunoreactivity at the adipogenesis stage, but enhanced hormone sensitive lipase (HSL) immunoreactivity at the lipolysis stage. Addition of protein kinase A (PKA) or protein kinase G (PKG) antagonist (KT5720 or KT5728) to adipocytes did not affect HSL immunoreactivity. However, KMUP-1 did increase HSL immunoreactivity and the effect was reduced by PKA or PKG antagonist. Simvastatin, theophylline, caffeine, and sildenafil, like KMUP-1, also enhanced HSL immunoreactivity. Phosphorylated HSL (p-HSL) was enhanced by KMUP-1, indicating increased lipolysis in mature 3T3-L1 adipocytes. Decreases of MAPKs/Akt/PPARγ during adipogenesis contributed to inhibition of adipocyte differentiation, and increases of PKA/PKG at lipolysis contributed to HSL activation and TG hydrolysis. Taken together, the data suggest that KMUP-1 can inhibit hyperadiposity in 3T3-L1 adipocytes.


Assuntos
Adipócitos/citologia , Adipogenia/efeitos dos fármacos , Piperidinas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Triglicerídeos/metabolismo , Xantinas/farmacologia , Células 3T3-L1 , Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Animais , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Proteínas Quinases Dependentes de GMP Cíclico/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Lipólise/efeitos dos fármacos , Camundongos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , PPAR gama/metabolismo , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Esterol Esterase/metabolismo
16.
Molecules ; 23(9)2018 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-30200192

RESUMO

Based on in silico results, recently we have assumed that FSCPX, an irreversible A1 adenosine receptor antagonist, inhibits the action of NBTI that is apparent on E/c curves of adenosine receptor agonists. As a mechanism for this unexpected effect, we hypothesized that FSCPX might modify the equilibrative and NBTI-sensitive nucleoside transporter (ENT1) in a way that allows ENT1 to transport adenosine but impedes NBTI to inhibit this transport. This assumption implies that our method developed to estimate receptor reserve for agonists with short half-life such as adenosine, in its original form, overestimates the receptor reserve. In this study, therefore, our goals were to experimentally test our assumption on this effect of FSCPX, to improve our receptor reserve-estimating method and then to compare the original and improved forms of this method. Thus, we improved our method and assessed the receptor reserve for the direct negative inotropic effect of adenosine with both forms of this method in guinea pig atria. We have found that FSCPX inhibits the effects of NBTI that are mediated by increasing the interstitial concentration of adenosine of endogenous (but not exogenous) origin. As a mechanism for this action of FSCPX, inhibition of enzymes participating in the interstitial adenosine production can be hypothesized, while modification of ENT1 can be excluded. Furthermore, we have shown that, in comparison with the improved form, the original version of our method overestimates receptor reserve but only to a small extent. Nevertheless, use of the improved form is recommended in the future.


Assuntos
Antagonistas do Receptor A1 de Adenosina/farmacologia , Adenosina/metabolismo , Átrios do Coração/efeitos dos fármacos , Átrios do Coração/metabolismo , Receptor A1 de Adenosina/metabolismo , Tioinosina/análogos & derivados , Xantinas/farmacologia , Antagonistas do Receptor A1 de Adenosina/química , Animais , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Cobaias , Tioinosina/farmacologia , Xantinas/química
17.
PLoS One ; 13(8): e0198881, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30157195

RESUMO

OBJECTIVE: To identify in vitro inhibitors of xanthine crystallization that have potential for inhibiting the formation of xanthine crystals in urine and preventing the development of the renal calculi in patients with xanthinuria. METHODS: The formation of xanthine crystals in synthetic urine and the effects of 10 potential crystallization inhibitors were assessed using a kinetic turbidimetric system with a photometer. The maximum concentration tested for each compound was: 20 mg/L for 3-methylxanthine (3-MX); 40 mg/L for 7-methylxanthine (7-MX), 1-methylxanthine (1-MX), theobromine (TB), theophylline, paraxanthine, and caffeine; 45 mg/L for 1-methyluric acid; 80 mg/L for 1,3-dimethyluric acid; and 200 mg/L for hypoxanthine. Scanning electron microscopy was used to examine the morphology of the crystals formed when inhibitory effects were observed. RESULTS: Only 7-MX, 3-MX, and 1-MX significantly inhibited xanthine crystallization at the tested concentrations. Mixtures of inhibitors had an additive effect rather than a synergistic effect on crystallization. CONCLUSION: Two of the inhibitors identified here-7-MX and 3-MX-are major metabolites of TB. In particular, after TB consumption, 20% is excreted in the urine as TB, 21.5% as 3-MX, and 36% as 7-MX. Thus, consumption of theobromine could protect patients with xanthinuria from the development of renal xanthine calculi. Clinical trials are necessary to demonstrate these effects in vivo.


Assuntos
Precipitação Química/efeitos dos fármacos , Cálculos Renais/química , Cálculos Renais/prevenção & controle , Urolitíase , Xantina/química , Xantinas/farmacologia , Aldeído Oxidase/deficiência , Aldeído Oxidase/urina , Cristalização , Regulação para Baixo/efeitos dos fármacos , Humanos , Técnicas In Vitro , Erros Inatos do Metabolismo/prevenção & controle , Erros Inatos do Metabolismo/urina , Erros Inatos do Metabolismo da Purina-Pirimidina/prevenção & controle , Erros Inatos do Metabolismo da Purina-Pirimidina/urina , Urolitíase/prevenção & controle , Urolitíase/urina , Xantina/antagonistas & inibidores , Xantina/urina , Xantina Desidrogenase/deficiência , Xantina Desidrogenase/urina
18.
Pharmacol Rep ; 70(4): 746-752, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29936361

RESUMO

BACKGROUND: Diabetes mellitus is a metabolic disorder characterized by chronic hyperglycemia accompanied by impaired vascular and endothelial function. Activation of ATP-sensitive potassium (KATP) channels can protect endothelial function against hypertension and hyperglycemia. KMUP-1, a xanthine derivative, has been demonstrated to modulate K+-channel activity in smooth muscles. This study investigated protective mechanisms of KMUP-1 in impaired mesenteric artery (MA) reactivity in streptozotocin (STZ)-induced diabetic rats. METHODS: Rats were divided into three groups: control, STZ (65 mg/kg, ip) and STZ + KMUP-1 (5 or 10 mg/kg/day, ip). MA reactivity was measured by dual wire myograph. MA smooth muscle cells (MASMCs) were enzymatically dissociated and the KATP currents recorded by a whole-cell patch-clamp technique. RESULTS: STZ decreased MA KATP currents in a time-course dependent manner and achieved steady inhibition at day 14. In the MASMCs of STZ-treated rats, KMUP-1 partially recovered the KATP currents, suggesting that vascular KATP channels were activated by KMUP-1. K+ (80 mM KCl)-induced MA contractions in STZ-treated rats were higher than those of control rats. KMUP-1 significantly attenuated STZ-stimulated MA contractions in response to high K+, suggesting that KMUP-1 may partly restore the vascular reactivity of MAs. In addition, STZ decreased the expression of endothelial nitric oxide synthase (eNOS) and this effect was reversed by KMUP-1, suggesting that KMUP-1 could improve STZ-induced vascular endothelial dysfunction. CONCLUSION: KMUP-1 prevents STZ impairment of MA reactivity, eNOS levels and KATP channels, and accordingly protects against vascular dysfunction in diabetic rats.


Assuntos
Diabetes Mellitus Experimental/complicações , Diabetes Mellitus Experimental/fisiopatologia , Canais KATP/metabolismo , Artérias Mesentéricas/fisiopatologia , Piperidinas/farmacologia , Doenças Vasculares/complicações , Doenças Vasculares/prevenção & controle , Xantinas/farmacologia , Animais , Diabetes Mellitus Experimental/metabolismo , Relação Dose-Resposta a Droga , Masculino , Potenciais da Membrana/fisiologia , Artérias Mesentéricas/metabolismo , Miócitos de Músculo Liso/fisiologia , Óxido Nítrico Sintase Tipo III/biossíntese , Potássio/farmacologia , Ratos , Fatores de Tempo , Doenças Vasculares/metabolismo , Doenças Vasculares/fisiopatologia
19.
Am J Physiol Cell Physiol ; 315(4): C558-C570, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-29898376

RESUMO

The epithelial barrier of the lung is destroyed during acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) due to the apoptosis of alveolar epithelial cells (AECs). Therefore, treatments that block AEC apoptosis might be a therapeutic strategy to ameliorate ALI. Based on recent evidence, A2B adenosine receptor (A2BAR) plays an important role in ALI in several different animal models, but its exact function in AECs has not been clarified. We investigated the role of A2BAR in AEC apoptosis in a mouse model of oleic acid (OA)-induced ALI and in hydrogen peroxide (H2O2)-induced AEC (A549 cells and MLE-12 cells) injury. Mice treated with BAY60-6583, a selective A2BAR agonist, showed lower AEC apoptosis rates than mice treated with OA. However, the role of BAY60-6583 in OA-induced ALI was attenuated by a specific blocker of A2BAR, PSB1115. A2BAR activation decreased H2O2-induced cell apoptosis in vitro, as characterized by the translocation of apoptotic proteins, the release of cytochrome c, and the activation of caspase-3 and poly (ADP ribose) polymerase 1 (PARP-1). In addition, apoptosis was required for the phosphorylation of ERK1/2, p38, and JNK. Importantly, compared with cells transfected with the A2BAR-siRNA, an ERK inhibitor or p38 inhibitor exhibited decreased apoptotic ratios and cleaved caspase-9 and cleaved PARP-1 levels, whereas the JNK inhibitor displayed increases in these parameters. In conclusion, A2BAR activation effectively attenuated OA-induced ALI by inhibiting AEC apoptosis and mitigated H2O2-induced AEC injury by suppressing the p38 and ERK1/2-mediated mitochondrial apoptosis pathway.


Assuntos
Lesão Pulmonar Aguda/metabolismo , Células Epiteliais Alveolares/metabolismo , Apoptose/fisiologia , Receptor A2B de Adenosina/metabolismo , Células A549 , Lesão Pulmonar Aguda/induzido quimicamente , Células Epiteliais Alveolares/efeitos dos fármacos , Aminopiridinas/farmacologia , Animais , Apoptose/efeitos dos fármacos , Caspase 3/metabolismo , Caspase 9/metabolismo , Linhagem Celular Tumoral , Humanos , Peróxido de Hidrogênio/farmacologia , Pulmão , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ácido Oleico/farmacologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Xantinas/farmacologia
20.
Eur J Pharmacol ; 833: 263-274, 2018 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-29886243

RESUMO

Microglia exhibit various activation phenotypes in the spinal cord after peripheral nerve injury, and promote neuropathic pain. Ibudilast is a phosphodiesterase inhibitor with anti-inflammatory activity, but its effect on activated microglia in chronic neuropathic pain is poorly understood. We investigated whether ibudilast was effective on established allodynia associated with activated microglial phenotypes in two rat models of peripheral and central neuropathic pain. A single intrathecal injection of ibudilast (25 µg) inhibited established allodynia on days 7-21 after sciatic nerve injury in rats. Repeated injections of ibudilast (25 µg/day) reduced the numbers of phosphorylated p38-positive cells without changing hypertrophic microglia, whereas minocycline (100 µg/day) decreased the numbers of hypertrophic microglia associated with phosphorylated p38 levels in the spinal cord. Gene analysis revealed that minocycline, but not ibudilast, increased the expression of anti-inflammatory cytokine genes Il10 and Tgfß1 in the spinal cord. Propentofylline (100 µg/day) was less effective on microglial phenotypes and established allodynia. Ibudilast inhibited persistent allodynia after the recovery of motor deficits in experimental autoimmune encephalomyelitis rats. Therefore, ibudilast might be effective for chronic neuropathic pain after peripheral and central nerve damage. Ibudilast mediated these effects on activated microglia using a different mechanism compared with minocycline and propentofylline.


Assuntos
Hiperalgesia/tratamento farmacológico , Microglia/efeitos dos fármacos , Neuralgia/tratamento farmacológico , Inibidores de Fosfodiesterase/farmacologia , Piridinas/farmacologia , Animais , Encefalomielite Autoimune Experimental/complicações , Encefalomielite Autoimune Experimental/etiologia , Feminino , Humanos , Hiperalgesia/etiologia , Injeções Espinhais , Masculino , Minociclina/farmacologia , Neuralgia/etiologia , Fármacos Neuroprotetores/farmacologia , Medição da Dor , Traumatismos dos Nervos Periféricos/complicações , Traumatismos dos Nervos Periféricos/etiologia , Inibidores de Fosfodiesterase/uso terapêutico , Fosforilação , Piridinas/uso terapêutico , Ratos , Ratos Endogâmicos Lew , Ratos Sprague-Dawley , Nervo Isquiático/lesões , Medula Espinal/citologia , Xantinas/farmacologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
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