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2.
Org Biomol Chem ; 17(37): 8618-8627, 2019 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-31528932

RESUMO

A rational approach that may be applied to a broad class of enzyme-catalyzed reactions to design enzyme inhibitors affords a powerful strategy, facilitating the development of drugs and/or molecular probes of enzyme mechanisms. A strategy for the development of substrate-product analogues (SPAs) as inhibitors of racemases and epimerases is elaborated using isoleucine 2-epimerase from Lactobacillus buchneri (LbIleE) as a model enzyme. LbIleE catalyzes the PLP-dependent, reversible, racemization or epimerization of nonpolar amino acids at the C-2 position. The enzyme plays an important role in the biosynthesis of branched-chain d-amino acids and is a potential target for the development of antimicrobial agents. 3-Ethyl-3-methyl-l-norvaline (Ki = 2.9 ± 0.2 mM) and 3-ethyl-3-methyl-d-norvaline (Ki = 1.5 ± 0.2 mM) were designed as SPAs based on the movement of the sec-butyl side chain of the substrate l-Ile during catalysis, and were competitive inhibitors with binding affinities exceeding that of l-Ile by 1.3- and 2.5-fold, respectively. Surprisingly, these compounds were not substrates, but the corresponding compounds lacking the 3-methyl group were substrates. Unlike serine, glutamate, and proline racemases, which exhibit stringent steric requirements at their active sites, the active site of LbIleE was amenable to binding bulky SPAs. Moreover, LbIleE bound the SPA 2,2-di-n-butylglycine (Ki = 11.0 ± 0.2 mM) as a competitive inhibitor, indicating that the hydrophobic binding pocket at the active site was sufficiently plastic to tolerate gem-dialkyl substitution at the α-carbon of an amino acid. Overall, these results reveal that amino acid racemases/epimerases are amenable to inhibition by SPAs provided that they possess a capacious active site.


Assuntos
Desenho de Fármacos , Inibidores Enzimáticos/farmacologia , Glicina/farmacologia , Isoleucina/antagonistas & inibidores , Lactobacillus/enzimologia , Racemases e Epimerases/antagonistas & inibidores , Valina/análogos & derivados , Sítios de Ligação/efeitos dos fármacos , Biocatálise/efeitos dos fármacos , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Glicina/análogos & derivados , Glicina/química , Isoleucina/metabolismo , Modelos Moleculares , Conformação Molecular , Racemases e Epimerases/metabolismo , Especificidade por Substrato , Valina/síntese química , Valina/química , Valina/farmacologia
3.
PLoS One ; 14(6): e0218220, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31199835

RESUMO

Bacterial endospores can survive harsh environmental conditions and long-term dormancy in the absence of nutrients, but can rapidly germinate under favorable conditions. In the present study, we employed transposon sequencing (Tn-seq) to identify genes with previously uncharacterized roles in spore germination. Identified genes that encoded spore inner membrane proteins were chosen for study of defined mutants, which exhibited delayed germination in several assays in response to varying germinants. Significantly slowed release of DPA indicated that mutants were affected in Stage I of germination. Several mutants exhibited phenotypic traits consistent with failure of a GerA germinant receptor-mediated response, while others appeared to have a more general loss of response to varied germinants. Use of a gerA-lacZ transcriptional fusion and quantitative western blotting of GerAC allowed mutants to be classified based upon normal or decreased gerA transcription and normal or reduced GerA accumulation. Fourteen genes were identified to have newly described roles within Bacillus spore germination. A more complete understanding of this process can contribute to the development of better spore decontamination procedures.


Assuntos
Bacillus subtilis , Proteínas de Bactérias , Proteínas de Membrana , Análise de Sequência de DNA , Esporos Bacterianos , Bacillus subtilis/genética , Bacillus subtilis/metabolismo , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/genética , Proteínas de Membrana/biossíntese , Proteínas de Membrana/genética , Esporos Bacterianos/genética , Esporos Bacterianos/crescimento & desenvolvimento , Transcrição Genética/efeitos dos fármacos , Valina/farmacologia
4.
J Psychosoc Nurs Ment Health Serv ; 57(5): 11-14, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31042295

RESUMO

Tardive dyskinesia (TD), the choreoathetoid movements of fingers, arms, legs, and trunk and irregular stereotypical movements of the mouth, face, and tongue, has been the scourge of antipsychotic medications since the approval of chlorpromazine. TD tends to occur late in treatment and sometimes remains after discontinuation of the antipsychotic medication. With the recent approval of two medications, valbenazine (Ingrezza®) and deutetrabenazine (Austedo®), there are now treatments for this disfiguring consequence of dopamine-blocking medications. The current article distinguishes the movement disorder adverse effects of dopamine antagonists, explains the putative mechanism of action, and describes how best to treat TD with the new vesicular monamine transporter 2 (VMAT2) medications now approved by the U.S. Food and Drug Administration. [Journal of Psychosocial Nursing and Mental Health Services, 57(5), 11-14.].


Assuntos
Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Discinesia Tardia/tratamento farmacológico , Tetrabenazina/análogos & derivados , Valina/análogos & derivados , Antipsicóticos/uso terapêutico , Clorpromazina/uso terapêutico , Humanos , Enfermagem Psiquiátrica , Tetrabenazina/farmacologia , Tetrabenazina/uso terapêutico , Valina/farmacologia , Valina/uso terapêutico
5.
J Dairy Sci ; 102(7): 6679-6681, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31103299

RESUMO

Our previous published work demonstrated that feeding rumen-degradable valine to late-lactation dairy cows increased milk production compared with control-fed cows, with a response that was equivalent to that of recombinant bovine somatotropin. To further elucidate the response mechanism, we hypothesized that thyroxine (T4) and triiodothyronine (T3), which are important regulators of basal metabolism, may be involved. Previous short-term studies have demonstrated increased milk production when feeding iodinated casein. Eight multiparous Holstein dairy cows (255 ± 26.4 d in milk) were blocked by milk yield (34.1 ± 8.25 kg/d) and randomly assigned to 1 of 4 treatments using a replicated 4 × 4 Latin square design with 21-d periods (7 d for dietary adaptation and 14 d for data collection). Treatments were control (CON), a single injection of recombinant bovine somatotropin (rbST), and synthetic valine fed at 40 (V40) or 80 (V80) g/cow per day. Cows were fed a total mixed ration with a distillers dried grains carrier fed at 113.4 g/d containing no valine or added valine. Blood samples were collected twice during wk 2 and 3 of each period for T3 and T4 analysis. Concentrations of T4 (3.28, 3.90, 3.98, and 3.87 µg/dL for CON, rbST, V40, and V80, respectively) were increased for cows receiving rbST, V40, and V80 compared with CON cows. Concentrations of T3 (125.7, 140.7, 148.8, and 139.7 ng/dL) were increased for cows receiving rbST, V40, and V80 compared with CON cows, with cows receiving V40 having the highest T3 concentrations. In conclusion, feeding rumen-degradable valine increases plasma T4 and T3 concentrations, which would explain the mechanism leading to increased milk production.


Assuntos
Ração Animal , Bovinos/sangue , Dieta/veterinária , Tiroxina/sangue , Tri-Iodotironina/sangue , Valina/farmacologia , Animais , Feminino , Hormônio do Crescimento/administração & dosagem , Hormônio do Crescimento/metabolismo , Lactação/fisiologia , Leite , Distribuição Aleatória , Rúmen/metabolismo , Valina/administração & dosagem
6.
J Biol Chem ; 294(21): 8543-8554, 2019 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-30940724

RESUMO

Prostate cancer is the second leading cause of cancer death among men in the United States. The androgen receptor (AR) antagonist enzalutamide is a Food and Drug Administration-approved drug for treatment of patients with late-stage prostate cancer and is currently under clinical study for early-stage prostate cancer treatment. After a short positive response period, tumors will develop drug resistance. In this study using RNA-Seq and bioinformatics analyses, we observed that NOTCH signaling is a deregulated pathway in enzalutamide-resistant cells. NOTCH2 and c-MYC gene expression positively correlated with AR expression in samples from patient with hormone refractory disease in which AR expression levels correspond to those typically observed in enzalutamide resistance. Cleaved NOTCH1, HES1 (Hes family BHLH transcription factor 1), and c-MYC protein expression levels are elevated in two enzalutamide-resistant cell lines, MR49F and C4-2R, indicating NOTCH signaling activation. Moreover, inhibition of the overexpressed ADAM metallopeptidase domain 10 (ADAM10) in the resistant cells induces an exclusive reduction in cleaved NOTCH1 expression. Furthermore, exposure of enzalutamide-resistant cells to both PF-03084014 and enzalutamide increased cell death, decreased colony formation ability, and resensitized cells to enzalutamide. Knockdown of NOTCH1 in C4-2R increased enzalutamide sensitivity by decreasing cell proliferation and increasing cleaved PARP expression. In a 22RV1 xenograft model, PF-03084014 and enzalutamide decreased tumor growth through reducing cell proliferation and increasing apoptosis. These results indicate that NOTCH1 signaling may contribute to enzalutamide resistance in prostate cancer, and inhibition of NOTCH signaling can resensitize resistant cells to enzalutamide.


Assuntos
Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Feniltioidantoína/análogos & derivados , Receptor Notch1/metabolismo , Transdução de Sinais/efeitos dos fármacos , Tetra-Hidronaftalenos/farmacologia , Valina/análogos & derivados , Animais , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos/genética , Humanos , Masculino , Camundongos , Camundongos Nus , Feniltioidantoína/farmacologia , Neoplasias da Próstata , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Receptor Notch1/genética , Receptor Notch2/genética , Receptor Notch2/metabolismo , Transdução de Sinais/genética , Fatores de Transcrição HES-1/genética , Fatores de Transcrição HES-1/metabolismo , Valina/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto
7.
Neuropharmacology ; 151: 64-73, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30943384

RESUMO

Behavioral studies using pharmacological tools have implicated histamine H1 receptors in cognitive function via their interactions with N-methyl-D-aspartate receptors (NMDARs) in the hippocampus. However, little is known about the neurophysiological mechanism that underlies the interaction between H1 receptors and NMDARs. To explore how H1 receptor activation affects hippocampal excitatory neurotransmission and synaptic plasticity, this study aimed to examine the effect of H1 receptor ligands on both NMDAR-mediated synaptic currents and long-term potentiation (LTP) at synapses between Schaffer collaterals and CA1 pyramidal neurons using acute mouse hippocampal slices. We found that the H1 receptor antagonist/inverse agonists, pyrilamine (0.1 µM) and cetirizine (10 µM), decreased the NMDAR-mediated component of stimulation-induced excitatory postsynaptic currents (EPSCs) recorded from CA1 pyramidal neurons without affecting the AMPA receptor-mediated component of EPSCs and its paired pulse ratio. Pretreatment of slices with either the glial metabolism inhibitor, fluoroacetate (5 mM), or D-serine (100 µM) diminished the pyrilamine- or cetirizine-induced attenuation of the NMDAR-mediated EPSCs. Furthermore, the LTP of field excitatory postsynaptic potentials induced following high frequency stimulation of Schaffer collaterals was attenuated with application of pyrilamine or cetirizine. Pretreatment with D-serine again attenuated the pyrilamine-induced suppression of LTP. Our data suggest that H1 receptors in the CA1 can undergo persistent activation induced by their constitutive receptor activity and/or tonic release of endogenous histamine, resulting in facilitation of the NMDAR activity in a manner dependent of astrocytes and the release of D-serine. This led to the enhancement of NMDA-component EPSC and LTP at the Schaffer collateral-CA1 pyramidal neuron synapses.


Assuntos
Astrócitos/efeitos dos fármacos , Região CA1 Hipocampal/efeitos dos fármacos , Antagonistas dos Receptores Histamínicos H1/farmacologia , Potenciação de Longa Duração/efeitos dos fármacos , Receptores Histamínicos H1/metabolismo , Serina/farmacologia , Animais , Astrócitos/metabolismo , Região CA1 Hipocampal/fisiologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Potenciação de Longa Duração/fisiologia , Camundongos , N-Metilaspartato/farmacologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Pirilamina/farmacologia , Receptores de N-Metil-D-Aspartato/agonistas , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Receptores de N-Metil-D-Aspartato/metabolismo , Valina/análogos & derivados , Valina/farmacologia
8.
Nutrients ; 11(4)2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-30999554

RESUMO

Although several kinds of amino acids (AAs) are known to affect physiological actions during exercise, little is known about the combined effects of a mixture of several AAs on fatigue during exercise. The aim of the present study was to investigate the effect of an AA mixture supplement containing arginine, valine, and serine on exercise-induced fatigue in healthy volunteers. These AAs were selected because they were expected to reduce fatigue during exercise by acting the positive effects synergistically. A randomized, double-blinded, placebo-controlled crossover trial was conducted. Thirty-nine males ingested an AA mixture containing 3600 mg of arginine, 2200 mg of valine, and 200 mg of serine or a placebo each day for 14 days. On the 14th day, the participants completed an exercise trial on a cycle ergometer at 50% of VO2max for 120 min. After the two-week washout period, the participants repeated the same trial with the other test sample. The participant's feeling of fatigue based on a visual analog scale (VAS) and a rating of perceived exertion (RPE), as well as blood and physical parameters were evaluated. The feeling of fatigue based on VAS and RPE were significantly improved in AA compared to those in placebo. In the blood analysis, the increase in serum total ketone bodies during exercise and plasma tryptophan/branched-chain amino acids were significantly lower in AA than those in placebo. The present study demonstrated that supplementation with an AA mixture containing arginine, valine, and serine reduced the feeling of fatigue during exercise. The AA mixture also changed several blood parameters, which may contribute to the anti-fatigue effect.


Assuntos
Arginina/administração & dosagem , Exercício Físico/fisiologia , Fadiga/prevenção & controle , Serina/administração & dosagem , Valina/administração & dosagem , Adulto , Arginina/farmacologia , Estudos Cross-Over , Método Duplo-Cego , Combinação de Medicamentos , Sinergismo Farmacológico , Fadiga/etiologia , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Serina/farmacologia , Valina/farmacologia
9.
Drug Test Anal ; 11(8): 1183-1191, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31021521

RESUMO

Indole- and indazole-based synthetic cannabinoid receptor agonists (SCRAs), featuring valine or tert-leucine substituents, are commonly abused new psychoactive substances (NPS). A major metabolic pathway for these SCRAs is hydrolysis of the terminal amide or methylester functionalities. Although these hydrolysis products were already detected as main ingredients in some "legal highs," these metabolites are often poorly characterized. Here, we report a systematic investigation of the activity of 7 common hydrolysis metabolites of 15 SCRAs featuring scaffolds based on L-valine or L-tert-leucine in direct comparison to their parent compounds. An activity-based cannabinoid receptor 1 (CB1 ) bio-assay was used for activity profiling of SCRAs and their metabolites in a stable HEK293T cell system. The recruitment of ß-arrestin2 to the activated CB1 (each fused to one part of a split Nanoluciferase) was provoked by adding the (putative) SCRAs. Luminescence of the functionally complemented luciferase was monitored by a 96-well plate-reader. The major hydrolysis metabolites of 5F-AB-PINACA, ADB-CHMICA, ADB-CHMINACA, ADB-FUBICA, and their methyl- and ethylester derivatives showed no detectable CB1 activation at concentrations up to 1 µM. On the other hand, metabolites of 5F-ADB-PINACA, AB-CHMINACA, and ADB-FUBINACA did retain activity, although significantly reduced as compared to the parent compounds (EC50 values >100 nM). Activity-based characterization of SCRAs and their metabolites at CB1 may not only allow a better insight into the complex interplay between SCRAs and their metabolites in intoxications, but may also allow application of the concept of "activity equivalents" present in biological fluids or, alternatively, in confiscated materials.


Assuntos
Agonistas de Receptores de Canabinoides/metabolismo , Agonistas de Receptores de Canabinoides/farmacologia , Valina/análogos & derivados , Valina/metabolismo , Valina/farmacologia , Agonistas de Receptores de Canabinoides/química , Drogas Desenhadas/química , Drogas Desenhadas/metabolismo , Drogas Desenhadas/farmacologia , Células HEK293 , Humanos , Psicotrópicos/química , Psicotrópicos/metabolismo , Psicotrópicos/farmacologia , Receptor CB1 de Canabinoide/agonistas , Receptor CB1 de Canabinoide/metabolismo , Valina/química
10.
Biomed Pharmacother ; 113: 108768, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30889486

RESUMO

Pulmonary fibrosis (PF) progression may be involved with arginine (Arg) metabolism and immune balance. The present study aimed to explore the effects of L-Arginine (L-Arg) and L-Norvaline (L-Nor) on bleomycin (BLM)-induced PF in mice, meanwhile, and observe dynamic changes of Arg metabolism, immune balance and crosstalk between them in PF progression. Followed intratracheal instillation of BLM or saline, Kunming mice were treated orally with saline, L-Arg, L-Nor and L-Arg + L-Nor three times a day. And the mice were sacrificed on Day 3, 14 and 28 after treatment. Changes of body weight, lung index, lung hydroxyproline and histopathology were analyzed to evaluate the PF degree. Peripheral blood Arg, Citrulline (Cit), Ornithine (Orn) and Proline (Pro), lung NO, NOS and arginase were analyzed to evaluate the Arg metabolism. Peripheral blood Tregs, Th17 and γδT cells were analyzed to evaluate the immune balance. Our data showed that combination of L-Arg and L-Nor dynamically reversed the weight loss, decreased lung index and hydroxyproline, and improved lung histopathological damages induced by BLM. The combination dynamically and significantly rectified Tregs, Th17, γδT and Tregs/Th17 abnormal changes. Meanwhile, these disorders of peripheral blood Arg, Cit, Orn, Pro, Orn/Cit and Pro/Orn, and lung NO, iNOS and TNOS were also improved accordingly. These results demonstrated that combination of L-Arg and L-Nor had inhibitory effects on BLM-induced PF progression, possibly due to their corrective action on immune imbalance, Arg metabolism disorder and crosstalk abnormality in the progression of PF.


Assuntos
Arginina/administração & dosagem , Pulmão/efeitos dos fármacos , Fibrose Pulmonar/prevenção & controle , Valina/análogos & derivados , Administração Oral , Animais , Arginina/farmacologia , Bleomicina/toxicidade , Modelos Animais de Doenças , Progressão da Doença , Quimioterapia Combinada , Linfócitos Intraepiteliais/imunologia , Pulmão/patologia , Masculino , Camundongos , Fibrose Pulmonar/imunologia , Fibrose Pulmonar/patologia , Linfócitos T Reguladores/imunologia , Células Th17/imunologia , Valina/administração & dosagem , Valina/farmacologia
11.
Clin Neuropharmacol ; 42(2): 37-41, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30870235

RESUMO

OBJECTIVES: The aim of this study was to review our "real-world" experience with the vesicular monoamine transporter 2 (VMAT2) inhibitors tetrabenazine (TBZ), deutetrabenazine (DTBZ), and valbenazine (VBZ) for treatment of hyperkinetic movement disorders. Access and adherence to VMAT2 inhibitors may be limited by insurance and regulatory issues, inexperience with their use by the prescribing physician, lack of efficacy, or side effects. METHODS: We performed a retrospective chart review, supplemented with a questionnaire, of all our patients treated with a VMAT2 inhibitor between January 1, 2017, and August 30, 2018. RESULTS: We identified 135 patients (57.8% male) and 178 prescriptions for VMAT2 inhibitors (TBZ, n = 45 [25.3%]; DTBZ, n = 104 [58.4%]; VBZ, n = 29 [16.3%]). Tourette syndrome/tics was the most common diagnosis (n = 67 [49.6%]) for which VMAT2 inhibitors were prescribed. The VMAT2 inhibitor mean treatment durations (range; SD) and daily dosages (range; SD) were as follows: TBZ (n = 31), 5.1 months (1-19; 3.9) at 48.8 mg (12.5-112.5; 29.6); DTBZ (n = 51), 8.0 months (0.25-16.5; 4.4) at 34.4 mg (6-96; 20.7); and VBZ (n = 20), 6.0 months (0.1-16; 5.6) at 64 mg (40-160; 35.3). The VMAT2 inhibitors effectively controlled hyperkinetic movement disorders as measured by a 1- to 4-point Likert scale (1 = normal or mildly ill, 4 = severely ill) comparing illness severity before starting and while on treatment (score of 1 in 13.0%-26.7% vs 60.9%-71.9% of patients). Side effects were mild and improved or resolved following dose reduction, drug cessation, or addition of adjunctive medications. CONCLUSIONS: The VMAT2 inhibitors are effective and safe in a range of hyperkinetic movement disorders but are not readily accessible by patients in the United States for indications not approved by the Food and Drug Administration.


Assuntos
Tetrabenazina/análogos & derivados , Tetrabenazina/uso terapêutico , Tiques/tratamento farmacológico , Síndrome de Tourette/tratamento farmacológico , Valina/análogos & derivados , Proteínas Vesiculares de Transporte de Monoamina/antagonistas & inibidores , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Tetrabenazina/farmacologia , Tiques/diagnóstico , Síndrome de Tourette/diagnóstico , Valina/farmacologia , Valina/uso terapêutico , Adulto Jovem
12.
Arch Anim Nutr ; 73(2): 75-87, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30821190

RESUMO

The present study investigated the hypothesis that dietary concentrations of leucine (Leu) in excess of the breeder´s recommendations activates protein synthesis and decreases protein degradation in muscle of broilers. Day-old male Ross 308 broilers (n = 450) were phase-fed corn-soybean meal-based diets during starter (d 1-10), grower (d 11-22), and finisher (d 23-34) period. The basal diets fed to the control group (L0) met the broilers' requirements for nutrients and amino acids, and contained Leu, Leu:isoleucine (Ile) and Leu:valine (Val) ratios, close to those recommended by the breeder (Leu:Ile: 100:54, 100:52, 100:51; Leu:Val 100:64, 100:61, 100:58; in starter, grower and finisher diet, resp.). Basal diets were supplemented with Leu to exceed the breeder's recommendations by 35% (group L35) and 60% (group L60). Growth performance during 34 d, and carcass weights, and breast and thigh muscle weights on d 34 were similar among groups. Hepatic and muscle mRNA levels of genes involved in the somatotropic axis [growth hormone receptor, insulin-like growth factor (IGF)-1, IGF binding protein 2, IGF receptor] on d 34 were not influenced by Leu. In the breast muscle, relative mRNA abundances of genes involved in the mammalian target of rapamycin (mTOR) pathway of protein synthesis (mTOR, ribosomal p70 S6 kinase) and the ubiquitin-proteasome pathway of protein degradation (F-box only protein 32, Forkhead box protein O1, Muscle RING-finger protein-1) on d 34 were largely similar among groups. Likewise, relative phosphorylation and thus activation of mTOR and ribosomal protein S6 involved in the mTOR pathway, and of eukaryotic translation initiation factor 2A (eIF2a) involved in the general control nonderepressible 2 (GCN2)/eIF2a pathway of protein synthesis inhibition, were not influenced. These data indicate that dietary Leu concentrations exceeding the broiler´s requirements up to 60% neither influence protein synthesis nor degradation pathways nor muscle growth in growing broilers.


Assuntos
Galinhas/fisiologia , Isoleucina/farmacologia , Leucina/farmacologia , Proteínas Musculares/metabolismo , Músculo Esquelético/metabolismo , Valina/farmacologia , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Composição Corporal , Dieta/veterinária , Suplementos Nutricionais , Regulação da Expressão Gênica/efeitos dos fármacos , Isoleucina/administração & dosagem , Leucina/administração & dosagem , Masculino , Proteínas Musculares/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Valina/administração & dosagem , Ganho de Peso
13.
Amino Acids ; 51(4): 717-726, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30798466

RESUMO

This study was conducted to determine the catabolism of L-valine in porcine mammary epithelial cells (PMECs) and its role in stimulating protein synthesis in these cells. PMECs were incubated with 0.05-, 0.10-, 0.25-, 0.5-, and 1.0-mM L-valine at 37 oC for 2 h. Cell viability and expressions of α-lactalbumin and ß-casein were measured after culture with L-valine for 3 days. L-[1-14C]valine was used to study valine catabolism, whereas [3H]phenylalanine was employed as a tracer to determine protein synthesis and degradation in PMECs. The abundances of proteins involved in the mTOR signaling pathway and the mRNA levels for the related key genes were determined using the western blot and RT-PCR techniques, respectively. Cell numbers and the synthesis of proteins (including α-lactalbumin and ß-casein) were greater (P < 0.05) in the presence of 0.5-mM L-valine, compared with 0.05- or 0.1-mM L-valine. L-Valine at 0.5 mM also enhanced (P < 0.05) the production of α-lactalbumin by PMECs, in comparison with 0.25 mM L-valine. Increasing the extracellular concentration of L-valine from 0.05 to 0.5 mM stimulated protein synthesis in a concentration-dependent manner without affecting proteolysis. Although L-valine was actively transaminated in PMECs, its α-ketoacid product (α-ketoisovalerate) at 0.05-0.2 mM did not affect protein synthesis or degradation in the cells. Thus, the effect of L-valine on protein synthesis was independent of its metabolism to yield α-ketoisovalerate. At the molecular level, 0.5-mM L-valine increased (P < 0.05) the mRNA levels for Ras, ERK1/2, and p70S6K, and the abundances of mTOR, p-4EBP1, total 4EBP1, p-ERK1/2, and total ERK1/2 proteins. These findings establish the critical role of L-valine in enhancing PMEC growth and milk protein synthesis possibly by regulating the mTOR and Ras/ERK signaling pathways. Further studies are warranted to understand how L-valine regulates gene expression and mTOR activation in PMECs.


Assuntos
Células Epiteliais/metabolismo , Glândulas Mamárias Animais/metabolismo , Biossíntese de Proteínas , Valina/farmacologia , Animais , Células Cultivadas , Células Epiteliais/citologia , Células Epiteliais/efeitos dos fármacos , Feminino , Glândulas Mamárias Animais/citologia , Glândulas Mamárias Animais/efeitos dos fármacos , Fosforilação , Transdução de Sinais , Suínos
14.
Appl Physiol Nutr Metab ; 44(6): 632-636, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30398915

RESUMO

Branched-chain amino acids (BCAA) are used as nutritional support for patients with a range of conditions including liver cirrhosis and in-born errors of amino acid metabolism, and they are commonly used "sports" or exercise supplements. The effects of the BCAA on the in-vitro activity of calf intestinal alkaline phosphatase (EC. 3.1.3.1) were studied. All three BCAA were found to be uncompetitive inhibitors of the enzyme with L-leucine being the most potent ( = 24.9 mmol/L) and L-valine, the least potent ( = 37 mmol/L). Mixed BCAA are able to act in combination to inhibit the enzyme. Given the important role of intestinal alkaline phosphatase in gut homeostasis, these findings have potential implications for those taking high levels of BCAA as supplements.


Assuntos
Fosfatase Alcalina/antagonistas & inibidores , Aminoácidos de Cadeia Ramificada/farmacologia , Animais , Bovinos , Suplementos Nutricionais , Leucina/farmacologia , Valina/farmacologia
15.
Poult Sci ; 98(3): 1310-1320, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30376070

RESUMO

Three different regression approaches were applied to determine the optimal digestible (d.) and analyzed Val:Lys ratios for broiler performance and carcass yield. One-day-old male Cobb 500 broilers (n = 960) were assigned to 1 of 8 diets, with 6 pens/diet and 20 birds/pen, for 42 days. The negative control consisted of the basal diet with a d.Val:d.Lys ratio of 0.63 and with 93% of the required d.Lys. The positive control consisted of the basal diet with a d.Val:d.Lys of 0.80, with no reduction in d.Lys content. The other (test) diets contained a range of d.Val:d.Lys ratios, all with 93% of the required d.Lys. Data on feed intake (FI), body weight gain (BWG), and feed conversion ratio (FCR) were submitted to regression analysis, applying quadratic polynomial (QP), exponential asymptotic (EA), and linear response plateau (LRP) models. Since Val did not affect carcass or breast meat yield, no regression was performed. Digestible and analyzed Val:Lys ratios were similar based on the regression models. The intercept between the QP and LRP models was used to determine the optimum Val:Lys ratio. Overall, the ideal d.Val:d.Lys ratio will vary according to the main goal of poultry production, i.e., BWG or FCR. For BWG, the ideal ratio was found to be 0.78 (0 to 12 d), 0.73 (0 to 28 d), and 0.76 (0 to 35 or 0 to 42 d). For FCR, the optimum d.Val:d.Lys was found to be 0.80 (0 to 12 d), 0.75 (0 to 28 d), and 0.78 (0 to 35 or 0 to 42 d). The optimum analyzed Val:Lys ratio was slightly higher. For instance, for BWG the optimum ratio was 0.80 (0 to 12 d), 0.76 (0 to 28 d), and 0.79 (0 to 35 or 0 to 42 d). For FCR, the optimum Val:Lys was 0.81 (0 to 12 d), 0.79 (0 to 28 d), and 0.81 (0 to 35 or 0 to 42 d). Valine did not affect carcass or breast meat yield.


Assuntos
Ração Animal/análise , Galinhas/fisiologia , Lisina/farmacologia , Valina/farmacologia , Fenômenos Fisiológicos da Nutrição Animal , Animais , Composição Corporal/efeitos dos fármacos , Dieta/veterinária , Digestão/fisiologia , Lisina/administração & dosagem , Masculino , Carne/análise , Análise de Regressão , Valina/administração & dosagem
16.
Poult Sci ; 98(3): 1272-1279, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30329096

RESUMO

An experiment was conducted to evaluate the total Valine (Val) requirement of first cycle laying hens from 41 to 60 wk of age. A total of 270 Hy-line W-36 laying hens were randomly assigned to 6 treatments with 15 replicate groups of 3 birds for each experimental unit. A Val deficient basal diet was formulated with corn and peanut meal with analyzed Val, Lys and crude protein concentrations of 0.515, 0.875, and 13.38%, respectively. Synthetic L-Val was supplemented to the basal diet in 0.070% increments to generate experimental diets containing 0.515, 0.585, 0.655, 0.725, 0.795, and 0.865% Val respectively. A controlled feeding program was applied during the experiment resulting in approximately 95 g feed intake per hen per day. Linear broken line, quadratic broken line, quadratic polynomial and exponential models were used to estimate the Val requirement of the hens based on hen-housed egg production (HHEP), egg mass (EM), and feed conversion ratio (FCR). Hen-housed egg production ranged from 48.3 to 81.4%, dependent upon dietary concentration of Val. Val requirements estimated by linear broken line, quadratic broken line, quadratic polynomial and exponential models were reported. Using the linear broken line model, the Val requirement was highest for egg mass, 597.3 mg/d, followed by egg production, 591.9 mg/d and lowest for FCR, 500.5 mg/d.


Assuntos
Ração Animal/análise , Galinhas/fisiologia , Valina/farmacologia , Animais , Dieta/veterinária , Ovos/normas , Feminino , Oviposição/efeitos dos fármacos , Valina/administração & dosagem
17.
Neuropsychopharmacology ; 44(2): 408-414, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-29849054

RESUMO

Prior learning can modify the plasticity mechanisms that are used to encode new information. For example, NMDA receptor (NMDAR) activation is typically required for new spatial and contextual learning in the hippocampus. However, once animals have acquired this information, they can learn new tasks even if NMDARs are blocked. This finding suggests that behavioral training alters cellular plasticity mechanisms such that NMDARs are not required for subsequent learning. The mechanisms that mediate this change are currently unknown. To address this issue, we tested the idea that changes in intrinsic excitability (induced by learning) facilitate the encoding of new memories via metabotropic glutamate receptor (mGluR) activation. Consistent with this hypothesis, hippocampal neurons exhibited increases in intrinsic excitability after learning that lasted for several days. This increase was selective and only observed in neurons that were activated by the learning event. When animals were trained on a new task during this period, excitable neurons were reactivated and memory formation required the activation of mGluRs instead of NMDARs. These data suggest that increases in intrinsic excitability may serve as a metaplastic mechanism for memory formation.


Assuntos
Condicionamento Clássico/efeitos dos fármacos , Antagonistas de Aminoácidos Excitatórios/farmacologia , Hipocampo/efeitos dos fármacos , Memória/efeitos dos fármacos , Plasticidade Neuronal/efeitos dos fármacos , Receptores de Glutamato Metabotrópico/antagonistas & inibidores , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Animais , Masculino , Camundongos , Neurônios/efeitos dos fármacos , Técnicas de Patch-Clamp , Valina/análogos & derivados , Valina/farmacologia
18.
J Pharm Pract ; 32(4): 450-457, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29455579

RESUMO

Tardive dyskinesia is a potentially irreversible, debilitating, hyperkinetic movement disorder that can result from dopamine receptor antagonists. Prompt recognition and resolution of symptoms are instrumental in preventing disease irreversibility, though current treatment options have fallen short of robust, effective, and long-term symptom control. In April 2017, the Food and Drug Administration (FDA) approved 2 new vesicular monoamine transporter 2 (VMAT2) inhibitors, deutetrabenazine and valbenazine, for chorea related to Huntington's disease and tardive dyskinesia, respectively. These agents were pharmacologically modified from tetrabenazine, a VMAT2 inhibitor used off-label in the treatment of tardive dyskinesia. Despite FDA-labeled indications of deutetrabenazine and valbenazine, each agent was explored as a treatment option for those with tardive dyskinesia. In this study, the pharmacologic modifications of the 2 new VMAT2 inhibitors are described, with detailed explanation as to how these may impact clinical practice. The associated case series, observational studies, and clinical trials exploring their use in the treatment of tardive dyskinesia are reported with expert opinion on practice implication.


Assuntos
Discinesia Tardia/tratamento farmacológico , Tetrabenazina/análogos & derivados , Proteínas Vesiculares de Transporte de Monoamina/antagonistas & inibidores , Inibidores da Captação Adrenérgica/administração & dosagem , Inibidores da Captação Adrenérgica/farmacologia , Antagonistas de Dopamina/efeitos adversos , Rotulagem de Medicamentos , Humanos , Discinesia Tardia/fisiopatologia , Tetrabenazina/administração & dosagem , Tetrabenazina/farmacologia , Valina/administração & dosagem , Valina/análogos & derivados , Valina/farmacologia , Proteínas Vesiculares de Transporte de Monoamina/metabolismo
19.
Elife ; 72018 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-30556810

RESUMO

Dopamine (D2) receptors provide autoinhibitory feedback onto dopamine neurons through well-known interactions with voltage-gated calcium channels and G protein-coupled inwardly-rectifying potassium (GIRK) channels. Here, we reveal a third major effector involved in D2R modulation of dopaminergic neurons - the sodium leak channel, NALCN. We found that activation of D2 receptors robustly inhibits isolated sodium leak currents in wild-type mice but not in NALCN conditional knockout mice. Intracellular GDP-ßS abolished the inhibition, indicating a G protein-dependent signaling mechanism. The application of dopamine reliably slowed pacemaking even when GIRK channels were pharmacologically blocked. Furthermore, while spontaneous activity was observed in nearly all dopaminergic neurons in wild-type mice, neurons from NALCN knockouts were mainly silent. Both observations demonstrate the critical importance of NALCN for pacemaking in dopaminergic neurons. Finally, we show that GABA-B receptor activation also produces inhibition of NALCN-mediated currents. Therefore, we identify NALCN as a core effector of inhibitory G protein-coupled receptors.


Assuntos
Canais de Cálcio Tipo N/metabolismo , Neurônios Dopaminérgicos/metabolismo , Canais de Potássio Corretores do Fluxo de Internalização Acoplados a Proteínas G/metabolismo , Canais Iônicos/genética , Proteínas do Tecido Nervoso/genética , Receptores de Dopamina D2/metabolismo , Receptores de GABA-B/metabolismo , 6-Ciano-7-nitroquinoxalina-2,3-diona/farmacologia , Animais , Canais de Cálcio Tipo N/genética , Dopamina/farmacologia , Neurônios Dopaminérgicos/citologia , Neurônios Dopaminérgicos/efeitos dos fármacos , 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/genética , Expressão Gênica , Guanosina Difosfato/análogos & derivados , Guanosina Difosfato/farmacologia , Canais Iônicos/deficiência , Transporte de Íons/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microtomia , Proteínas do Tecido Nervoso/deficiência , Técnicas de Patch-Clamp , Picrotoxina/farmacologia , Receptores de Dopamina D2/genética , Receptores de GABA-B/genética , Tionucleotídeos/farmacologia , Técnicas de Cultura de Tecidos , Valina/análogos & derivados , Valina/farmacologia , Área Tegmentar Ventral/citologia , Área Tegmentar Ventral/metabolismo
20.
Pestic Biochem Physiol ; 152: 76-83, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30497714

RESUMO

Iprovalicarb is a carboxylic acid amide (CAA) fungicide, highly effective in the control of potato late blight, causing by Phytophthora infestans. Due to cross-resistance with other CAA fungicides and moderate resistance risk of P. capsici to iprovalicarb, the evolutionary risk of P. infestans resistance to this fungicide and the contribution of inherited genes and environmental effect was evaluated using a common garden experiment. The results showed that the ratio of heritability and plasticity of iprovalicarb in the seven populations equaled 1.0, indicating both inherited genes and environmental factors were essential to iprovalicarb sensitivity in P. infestans. The pairwise population differentiation determined by SSR loci (FST) between populations ranged from 0.007 to 0.133 and the overall FST was significantly higher than population differentiation in RGR (QST), suggesting constraining selection acting on iprovalicarb sensitivity. We also found a new indicator of growth rate inhibition (GRI) for fungicide sensitivity, which was negatively correlated to growth rate in the absence of iprovalicarb, indicating a trade-off between iprovalicarb resistance and pathogen's growth. The constraining selection plus a trade-off between GRI and growth rate revealed low risk of P. infestans evolving resistance to iprovalicarb.


Assuntos
Carbamatos/farmacologia , Resistência a Medicamentos , Fungicidas Industriais/farmacologia , Phytophthora infestans/efeitos dos fármacos , Valina/análogos & derivados , Fenótipo , Phytophthora infestans/genética , Valina/farmacologia
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