Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
1.
Endocrinology ; 165(5)2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38368624

RESUMO

Glucoprivic feeding is one of several counterregulatory responses (CRRs) that facilitates restoration of euglycemia following acute glucose deficit (glucoprivation). Our previous work established that glucoprivic feeding requires ventrolateral medullary (VLM) catecholamine (CA) neurons that coexpress neuropeptide Y (NPY). However, the connections by which VLM CA/NPY neurons trigger increased feeding are uncertain. We have previously shown that glucoprivation, induced by an anti-glycolygic agent 2-deoxy-D-glucose (2DG), activates perifornical lateral hypothalamus (PeFLH) neurons and that expression of NPY in the VLM CA/NPY neurons is required for glucoprivic feeding. We therefore hypothesized that glucoprivic feeding and possibly other CRRs require NPY-sensitive PeFLH neurons. To test this, we used the ribosomal toxin conjugate NPY-saporin (NPY-SAP) to selectively lesion NPY receptor-expressing neurons in the PeFLH of male rats. We found that NPY-SAP destroyed a significant number of PeFLH neurons, including those expressing orexin, but not those expressing melanin-concentrating hormone. The PeFLH NPY-SAP lesions attenuated 2DG-induced feeding but did not affect 2DG-induced increase in locomotor activity, sympathoadrenal hyperglycemia, or corticosterone release. The 2DG-induced feeding response was also significantly attenuated in NPY-SAP-treated female rats. Interestingly, PeFLH NPY-SAP lesioned male rats had reduced body weights and decreased dark cycle feeding, but this effect was not seen in female rats. We conclude that a NPY projection to the PeFLH is necessary for glucoprivic feeding, but not locomotor activity, hyperglycemia, or corticosterone release, in both male and female rats.


Assuntos
Comportamento Alimentar , Hipotálamo , Neurônios , Neuropeptídeo Y , Ratos Sprague-Dawley , Animais , Feminino , Masculino , Ratos , Desoxiglucose/farmacologia , Ingestão de Alimentos/efeitos dos fármacos , Ingestão de Alimentos/fisiologia , Comportamento Alimentar/efeitos dos fármacos , Glucose/metabolismo , Região Hipotalâmica Lateral/metabolismo , Região Hipotalâmica Lateral/efeitos dos fármacos , Hormônios Hipotalâmicos/metabolismo , Hipotálamo/metabolismo , Hipotálamo/efeitos dos fármacos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Melaninas/metabolismo , Neurônios/metabolismo , Neurônios/efeitos dos fármacos , Neuropeptídeo Y/metabolismo , Neuropeptídeo Y/farmacologia , Neuropeptídeos/metabolismo , Orexinas/metabolismo , Hormônios Hipofisários/metabolismo , Receptores de Neuropeptídeo Y/metabolismo , Receptores de Neuropeptídeo Y/genética , Proteínas Inativadoras de Ribossomos Tipo 1/farmacologia , Saporinas/farmacologia
2.
Food Chem ; 412: 135558, 2023 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-36716631

RESUMO

Palm olein (POL) was modified by enzymatic interesterification with different degrees of acyl migration in a solvent-free packed bed reactor. The fatty acid and acylglycerol composition, isomer content, thermodynamic behavior, and relationship between crystal polymorphism, solid fat content (SFC), crystal microstructure, and texture before and after modification were studied. We found that the increase in sn-2 saturation interesterification was not only due to the generated tripalmitin (PPP) but also caused by acyl migration, and the SFC profiles were changed accordingly. The emergence of high melting point acylglycerols was an important factor accelerating the crystallization rate, further shortening the crystallization induction time, leading to the formation of large crystal spherulites, thereby reducing the hardness. The transformation from the ß' to the ß form occurred during post-hardening during storage. The isomer content also affected the physicochemical properties of the modified POL.


Assuntos
Lipase , Óleos de Plantas , Óleo de Palmeira/química , Óleos de Plantas/química , Lipase/química , Ácidos Graxos/química , Triglicerídeos/química , Glicerídeos/química , Catálise
3.
Chin J Integr Med ; 29(1): 3-9, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35915317

RESUMO

OBJECTIVE: To evaluate the efficacy and safety of Cidan Capsule combined with adjuvant transarterial chemoembolization (TACE) in patients with a high risk of early recurrence after curative resection of hepatocellular carcinoma (HCC). METHODS: A multicenter, randomized controlled trial was conducted in patients with high-risk recurrence factors after curative resection of HCC from 9 medical centers between July 2014 and July 2018. Totally 249 patients were randomly assigned to TACE with or without Cidan Capsule administration groups by stratified block in a 1:1 ratio. Postoperative adjuvant TACE was given 4-5 weeks after hepatic resection in both groups. Additionally, 125 patients in the TACE plus Cidan group were administrated Cidan Capsule (0.27 g/capsule, 5 capsules every time, 4 times a day) for 6 months with a 24-month follow-up. Primary endpoints included disease-free survival (DFS) and tumor recurrence rate (TRR). Secondary endpoint was overall survival (OS). Any drug-related adverse events (AEs) were observed and recorded. RESULTS: As the data cutoff in July 9th, 2018, the median DFS was not reached in the TACE plus Cidan group and 234.0 days in the TACE group (hazard ratio, 0.420, 95% confidence interval, 0.290-0.608; P<0.01). The 1- and 2-year TRR in the TACE plus Cidan and TACE groups were 31.5%, 37.1%, and 60.8%, 63.4%, respectively (P<0.01). Median OS was not reached in both groups. The 1- and 2-year OS rates in TACE plus Cidan and TACE groups were 98.4%, 98.4%, and 89.5%, 87.9%, respectively (P<0.05). The most common grade 3-4 AEs included fatigue, abdominal pain, lumbar pain, and nausea. One serious AE was reported in 1 patient in the TACE plus Cidan group, the death was due to retroperitoneal mass hemorrhage and hemorrhagic shock, and was not related to study drug. CONCLUSIONS: Cidan Capsule in combination with TACE can reduce the incidence of early recurrence in HCC patients at high-risk of recurrence after radical hepatectomy and may be an appropriate option in postoperative anti-recurrence treatment. (Registration No. NCT02253511).


Assuntos
Carcinoma Hepatocelular , Quimioembolização Terapêutica , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/cirurgia , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/patologia , Quimioembolização Terapêutica/efeitos adversos , Hepatectomia , Intervalo Livre de Doença , Resultado do Tratamento , Estudos Retrospectivos
4.
Food Chem ; 347: 129070, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33482483

RESUMO

Interesterification is widely employed as an effective technique to modify oils and fats. This study utilizes palm-based oil (palm olein: palm kernel oil: palm stearin, 5:3:2, w/w/w) as the raw material for the interesterification process performed in a pilot-scale packed bed reactor. Enzymatic interesterification (EIE) was catalyzed by Lipozyme TL IM (813.0 g) at 60℃ with reaction flow rate of 100 mL/min. Chemical interesterification (CIE) was catalyzed using sodium methoxide (0.3 wt%) as catalyst at 105 °C for 30 min. The results showed that the EIE fats had lower solid fat content tendency compared to that of CIE fats. The crystallization onset temperature was higher in EIE fats (23.09℃) compared to that of CIE (19.08℃). The results were consistent with the crystallization kinetics whereby the Avrami K constants of EIE fats were higher than that of CIE fats at various temperatures, indicating rapid crystallization and instant nucleation. Linear growth mechanism was dominant and the crystals formed were smaller in size as observed using polarized light microscope. The interesterified fats exhibited the presence of ß and ß'-crystals. While most of the tocopherol content was retained after EIE (386.18 ug/g), the molecular distillation process reduced the tocopherol concentration (110.01 ug/g) which consequently affected the oxidative stability. The findings in this work contribute to the fundamental understanding on the differences between CIE and EIE fats and provides data to support the preparation of modified fats via EIE that shows great potential as a controllable technique for industrialization.


Assuntos
Ácidos Graxos/química , Óleo de Palmeira/química , Biocatálise , Cristalização , Esterificação , Cinética , Lipase/metabolismo , Ácido Oleico/química , Oxirredução , Reologia , Ácidos Esteáricos/química , Termodinâmica
5.
J Agric Food Chem ; 69(32): 9056-9066, 2021 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-33433208

RESUMO

Acyl migration of fatty acid at sn-2 is often observed alongside enzymatic interesterification (EIE), causing the loss of lipase selectivity toward the acyl group at sn-1,3. In this study, an oil blend consisting of palm stearin (PST) and palm olein (POL) was interesterified via a chemical interesterification (CIE) and enzymatic method using a packed bed reactor. Characterization in terms of the triacylglycerol (TAG) compositions, sn-2 fatty acid distributions, and solid fat content profiles was performed. In comparison to that of CIE fats, EIE fats showed different modification effects on the solid fat content. Under similar reaction conditions, different interesterification degrees (IDs) were obtained according to the various blend ratios. Using the same mass ratio of substrates (POL/PST of 9:1), the EIE reaction time and temperature affected the ID and the change in the fatty acyl group at the sn-2 position. Under the reaction time of 46 min, an ID of 94.41% was acquired, while at 80 °C, the degree of acyl migration at sn-2 was 92.87%. EIE with high acyl migration exhibited a lower crystallization rate than that of EIE with low acyl migration. However, the effect of acyl migration on crystal polymorphism and oxidative stability was insignificant. Outcomes from this study are meaningful for the establishment of a theoretical basis for a controlled positional-specific EIE that is catalyzed by sn-1,3-specific lipase.


Assuntos
Lipase , Óleos de Plantas , Catálise , Esterificação , Ácidos Graxos , Lipase/metabolismo , Óleo de Palmeira , Triglicerídeos
6.
Food Funct ; 8(9): 3145-3154, 2017 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-28776625

RESUMO

This research studies the in-depth characteristics including the binding interactions and morphological structure of tannic acid (TA)/grape seed proanthocyanidins (GSP) and gelatin (GLT) colloidal complexes, and evaluated the stability and lipid oxidation of emulsions formed by the colloidal complexes. Polyphenol and GLT (1.2 wt%) self-assembled complexes were fabricated by varying the mass ratio (1 : 16, 1 : 8 and 1 : 4) and pH in the range of 3-7. TA and GSP can form stable colloidal complexes with GLT at the nanoscale at pH 6, as shown by the particle size results, and the complexes exhibited a spherical morphology as seen by transmission electron microscopy. Hydrogen bonding was the main binding force for the interaction between polyphenols and GLT. The antioxidant activity of GLT was greatly improved after complexing with polyphenols. The oil/water emulsion formed by the complexes had a smaller droplet size and higher lipid oxidation stability during storage. This was largely due to the physical barrier formed by polyphenol-GLT colloidal complexes at the oil-water interface, which can prevent the pro-oxidant from penetrating into oil. These results clarified the structural, morphological and antioxidant properties of polyphenol-gelatin non-covalent complexes, which is of great value for their application in food solutions as well as in emulsion systems.


Assuntos
Emulsões/química , Gelatina/química , Extrato de Sementes de Uva/química , Polifenóis/química , Proantocianidinas/química , Antioxidantes/química , Coloides/química , Ligação de Hidrogênio , Tamanho da Partícula , Taninos/química
7.
Artigo em Inglês | MEDLINE | ID: mdl-27555762

RESUMO

OBJECTIVES: Cellular senescence is a state of irreversible growth arrest induced either by telomere shortening (replicative senescence) or stress. The bronchial epithelial cell is often injured by inhaled toxic substances, such as cigarette smoke. In the present study, we investigated whether exposure to cigarette smoke extract (CSE) induces senescence of bronchial epithelial cells; and Cordyceps sinensis mechanism of inhibition of CSE-induced cellular senescence. METHODS: Human bronchial epithelial cells (16HBE cells) cultured in vitro were treated with CSE and/or C. sinensis. p16, p21, and senescence-associated-galactosidase activity were used to detect cellular senescence with immunofluorescence, quantitative polymerase chain reaction, and Western blotting. Reactive oxygen species (ROS), PI3K/AKT/mTOR and their phosphorylated proteins were examined to testify the activation of signaling pathway by ROS fluorescent staining and Western blotting. Then, inhibitors of ROS and PI3K were used to further confirm the function of this pathway. RESULTS: Cellular senescence was upregulated by CSE treatment, and C. sinensis can decrease CSE-induced cellular senescence. Activation of ROS/PI3K/AKT/mTOR signaling pathway was enhanced by CSE treatment, and decreased when C. sinensis was added. Blocking ROS/PI3K/AKT/mTOR signaling pathway can attenuate CSE-induced cellular senescence. CONCLUSION: CSE can induce cellular senescence in human bronchial epithelial cells, and ROS/PI3K/AKT/mTOR signaling pathway may play an important role in this process. C. sinensis can inhibit the CSE-induced senescence.


Assuntos
Brônquios/efeitos dos fármacos , Senescência Celular/efeitos dos fármacos , Cordyceps/química , Células Epiteliais/efeitos dos fármacos , Extratos Vegetais/farmacologia , Fumaça/efeitos adversos , Fumar/efeitos adversos , Brônquios/metabolismo , Brônquios/patologia , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular , Citoproteção , Relação Dose-Resposta a Droga , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Humanos , Fosfatidilinositol 3-Quinase/metabolismo , Fitoterapia , Extratos Vegetais/isolamento & purificação , Plantas Medicinais , Proteínas Proto-Oncogênicas c-akt/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismo , Fatores de Tempo
8.
J Acoust Soc Am ; 137(5): 2801-10, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25994708

RESUMO

The ideal binary mask (IBM) that was originally defined in anechoic conditions has been found to yield substantial improvements in speech intelligibility in noise. The IBM has recently been extended to reverberant conditions where the direct sound and early reflections of target speech are regarded as the desired signal. It is of great interest to know how the division between early and late reflections impacts on the intelligibility of the IBM-processed noisy reverberant speech. In this present study, the division between early and late reflections in three rooms was first determined by four typical estimation approaches and then used to compute the IBMs in reverberant conditions. The IBMs were then applied to the noisy reverberant mixture signal for segregating the desired signal, and the segregated signal was further presented to normal-hearing listeners for word recognition. Results showed that the IBMs with different divisions between early and late reflections provided substantial improvements in speech intelligibility over the unprocessed mixture signals in all conditions tested, and there were small, but statistically significant, differences in speech intelligibility between the different IBMs in some conditions tested.


Assuntos
Ruído/efeitos adversos , Mascaramento Perceptivo , Acústica da Fala , Inteligibilidade da Fala , Percepção da Fala , Qualidade da Voz , Estimulação Acústica , Acústica , Adulto , Audiometria da Fala , Feminino , Humanos , Masculino , Modelos Estatísticos , Reconhecimento Psicológico , Espectrografia do Som , Fatores de Tempo , Vibração , Adulto Jovem
9.
Environ Monit Assess ; 187(6): 344, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25963765

RESUMO

Supervised field trials at two locations in 2012 and 2013 were conducted to evaluate the dissipation, terminal residues, and safety evaluation of Nativo 75 water dispersible granule (WG) (25 % trifloxystrobin + 50 % tebuconazole) on ginseng and soil following foliar application at a recommended dose 150 (50 + 100) and 1.5 times of the recommended dosage 225 (75 + 150) g a.i. ha(-1). The average recoveries of trifloxystrobin and tebuconazole at three spiking levels in ginseng root, stem, and leaf and in soil were in the ranges of 81.0-96.8 % and 80.2-97.5 % with relative standard deviations (RSDs) of 4.92-13.13 % and 4.67-8.35 %, respectively. The half-lives of trifloxystrobin and tebuconazole were 5.92-9.76 days and 4.59-7.53 days, respectively. The terminal residues were all below the maximum residue limits (MRLs) of EU, USA, Canada, Japan, and South Korea. The food safety was evaluated by comparing the estimated daily intake (IEDI) with its acceptable daily intake (ADI). IEDI values calculated from residue data were found to be far less than the ADI on ginseng. Therefore, it would be unlikely to cause health problems induced by Nativo 75 WG use on ginseng at a dosage of 150-225 g a.i. ha(-1).


Assuntos
Acetatos/análise , Fungicidas Industriais/análise , Iminas/análise , Panax/química , Resíduos de Praguicidas/análise , Triazóis/análise , Monitoramento Ambiental , Meia-Vida , Metacrilatos/análise , Folhas de Planta/química , Caules de Planta/química , Solo/química , Poluentes do Solo/análise , Estrobilurinas
10.
Environ Monit Assess ; 187(1): 4126, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25446716

RESUMO

The dissipation and terminal residues of a fungicide suspension (5% hexaconazole, 25% kresoxim-methyl) in ginseng and soil were investigated by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). At fortified levels of 0.01, 0.02, and 0.20 mg kg(-1), the recoveries of hexaconazole and kresoxim-methyl were in the range of 80.6∼94.8% and 82.4∼98.8% with relative standard deviation of 3.42-9.12% and 3.19-8.58%, respectively. The half-lives were 7.09-10.73 days in root, 6.80-7.95 days in stem, 5.31-8.49 days in leaf, and 6.30-7.97 days in soil. The terminal residues were all below the maximum residue limits (MRLs) of EU and South Korea. Risk assessment results indicated that the risk of hexaconazole and kresoxim-methyl use in ginseng at dosage of 60-90 g a.i. ha(-1) was negligible to humans. This work would help the government to establish the MRL and provide guidance on the proper and safe use of hexaconazole and kresoxim-methyl in ginseng.


Assuntos
Fungicidas Industriais/análise , Panax/química , Resíduos de Praguicidas/análise , Fenilacetatos/análise , Solo/química , Triazóis/análise , Cromatografia Líquida de Alta Pressão , Monitoramento Ambiental , Meia-Vida , Metacrilatos/análise , Folhas de Planta/química , Raízes de Plantas/química , Caules de Planta/química , República da Coreia , Poluentes do Solo/análise , Estrobilurinas , Espectrometria de Massas em Tandem
11.
World J Gastroenterol ; 20(17): 4953-62, 2014 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-24833845

RESUMO

AIM: To clarify whether histone deacetylase inhibitors histone deacetylase inhibitors (HDACIs) can sensitize hepatocellular carcinoma (HCC) cells to sorafenib treatment. METHODS: Bax, Bcl-2, ATG5-ATG12, p21, and p27 protein levels in Hep3B, HepG2, and PLC/PRF/5 cells were examined by Western blot. CCK8 and a fluorometric caspase-3 assay were used to examine cellular viability and apoptosis levels. The effect of Beclin-1 on sensitization of HCC cells to sorafenib was examined by transfecting Beclin-1 siRNA into Hep3B, HepG2, and PLC/PRF/5 cells. RESULTS: Autophagy inhibition enhances the inhibitory effects of vorinostat and sorafenib alone or in combination on HCC cell growth. Vorinostat and sorafenib synergistically induced apoptosis and cell cycle alterations. Western blot data indicated that HDACIs and Beclin-1 knockdown increased the p53 acetylation level. The knockdown of Beclin-1 enhanced the synergistic effect of the combination of vorinostat with sorafenib. CONCLUSION: HDACIs can sensitize HCC cells to sorafenib treatment by regulating the acetylation level of Beclin-1.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Autofagia , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/patologia , Acetilação , Apoptose/efeitos dos fármacos , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Proteína Beclina-1 , Carcinoma Hepatocelular/enzimologia , Carcinoma Hepatocelular/genética , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Regulação Neoplásica da Expressão Gênica , Células Hep G2 , Inibidores de Histona Desacetilases/farmacologia , Humanos , Ácidos Hidroxâmicos/farmacologia , Neoplasias Hepáticas/enzimologia , Neoplasias Hepáticas/genética , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Niacinamida/análogos & derivados , Niacinamida/farmacologia , Compostos de Fenilureia/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Interferência de RNA , Sorafenibe , Transfecção , Proteína Supressora de Tumor p53/metabolismo , Vorinostat
12.
Chemosphere ; 93(4): 590-6, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23800595

RESUMO

Both grate and fluidized bed incinerators are widely used for MSW incineration in China. CaO addition for removing hazardous emissions from MSWI flue gas changes the characteristics of fly ash and affects the thermal behavior of heavy metals when the ash is reheated. In the present work, two types of MSWI fly ashes, sampled from both grate and fluidized bed incinerators respectively, were thermal treated at 1023-1323 K and the fate of heavy metals was observed. The results show that both of the fly ashes were rich in Ca and Ca-compounds were the main alkaline matter which strongly affected the leaching behavior of heavy metals. Ca was mostly in the forms of Ca(OH)2 and CaCO3 in the fly ash from grate incinerator in which nascent fly ash particles were covered by Ca-compounds. In contrast, the content of Ca was lower in the fly ash from fluidized bed incinerator and Ca was mostly in the form of CaSO4. Chemical reactions among Ca-compounds caused particle agglomeration in thermal treated fly ash from grate incinerator, restraining the heavy metals volatilization. In thermal treated fly ash from fluidized bed incinerator, Ca was converted into aluminosilicates especially at 1323 K which enhanced heavy metals immobilization, decreasing their volatile fractions as well as leaching concentrations. Particle agglomeration hardly affected the leaching behavior of heavy metals. However, it suppressed the leachable-CaCrO4 formation and lowered Cr leaching concentration.


Assuntos
Poluentes Atmosféricos/análise , Compostos de Cálcio/química , Cinza de Carvão/análise , Incineração/métodos , Metais Pesados/análise , Óxidos/química , Eliminação de Resíduos/métodos , Volatilização
13.
Bioresour Technol ; 136: 595-603, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23567736

RESUMO

This study investigates the non-isothermal mechanism and kinetic behaviour of gasification of a lower sulphur petroleum coke, sugar cane bagasse and blends under carbon dioxide atmosphere conditions using the thermogravimetric analyser (TGA). The gas products were measured online with coupled Fourier transform infrared spectroscopy (FTIR). The achieved results explored that the sugar cane bagasse and blend gasification happened in two steps: at (<500 °C) the volatiles are released, and at (>700 °C) char gasification occurred, whereas the lower sulphur petroleum coke presented only one char gasification stage at (>800 °C). Significant interactions were observed in the whole process. Some solid-state mechanisms were studied by the Coats-Redfern method in order to observe the mechanisms responsible for the gasification of samples. The results show that the chemical first order reaction is the best responsible mechanism for whole process. The main released gases are CO2, CO, CH4, HCOOH, C6H5OH and CH3COOH.


Assuntos
Dióxido de Carbono/química , Celulose/química , Coque/análise , Petróleo/análise , Enxofre/química , Termogravimetria/métodos , Cinética , Saccharum , Espectroscopia de Infravermelho com Transformada de Fourier
15.
Endocrinology ; 147(7): 3428-34, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16614076

RESUMO

Hindbrain catecholaminergic neurons are key participants in systemic glucoregulation. However, the specific subpopulations critical for glucoregulatory function have not been fully identified. Here we used in situ hybridization and immunohistochemistry to investigate effects of glucoprivation on expression of the gene for the catecholamine biosynthetic enzyme, dopamine-beta-hydroxylase (DBH), to further localize the critical cell populations. Glucoprivation induced by the glycolytic inhibitor, 2-deoxy-D-glucose (2DG) (250 mg/kg) increased total DBH mRNA expression in caudal ventrolateral medullary cell groups (namely A1, the A1/C1 overlap, and the middle portion of C1) from six to 49 times control levels. In retrofacial C1, no enhancement was observed. In the dorsomedial medulla, hybridization signal was modestly increased (tripled) in A2 but was not increased in the area postrema. Previous microinjection of the retrogradely transported catecholamine immunotoxin (anti-DBH-saporin, or DSAP) into the paraventricular nucleus of the hypothalamus reduced the number of DBH-immunoreactive cells in cell groups known to project to the paraventricular nucleus of the hypothalamus as well as reducing the 2DG-stimulated increases in total DBH mRNA expression in the caudal ventrolateral medulla and A2. The strong enhancement of DBH gene expression by glucoprivation is consistent with the demonstrated importance of catecholaminergic neurons for glucoregulation. The differential sensitivity of these neurons to glucoprivation is evidence of functional specialization within the total population. The pattern of 2DG-induced gene expression indicates that the ventrolateral medulla contains the vast majority of catecholamine neurons responsive to glucoprivation.


Assuntos
Catecolaminas/metabolismo , Dopamina beta-Hidroxilase/genética , Dopamina beta-Hidroxilase/metabolismo , Regulação da Expressão Gênica , Glucose/metabolismo , Animais , Desoxiglucose/metabolismo , Hipotálamo/metabolismo , Imuno-Histoquímica , Masculino , Neurônios/metabolismo , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Rombencéfalo/metabolismo
16.
Endocrinology ; 146(3): 1179-91, 2005 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15604214

RESUMO

Neuropeptide Y (NPY) conjugated to saporin (NPY-SAP), a ribosomal inactivating toxin, is a newly developed compound designed to selectively target and lesion NPY receptor-expressing cells. We injected NPY-SAP into the basomedial hypothalamus (BMH), just dorsal to the arcuate nucleus (ARC), to investigate its neurotoxicity and to determine whether ARC NPY neurons are required for glucoprivic feeding. We found that NPY-SAP profoundly reduced NPY Y1 receptor and alpha MSH immunoreactivity, as well as NPY, Agouti gene-related protein (AGRP), and cocaine and amphetamine-related transcript mRNA expression in the BMH. NPY-SAP lesions were localized to the injection site with no evidence of retrograde transport by hindbrain NPY neurons with BMH terminals. These lesions impaired responses to intracerebroventricular (icv) leptin (5 microg/5 microl x d) and ghrelin (2 microg/5 microl), which are thought to alter feeding primarily by actions on ARC NPY/AGRP and proopiomelanocortin/cocaine and amphetamine-related transcript neurons. However, the hypothesis that NPY/AGRP neurons are required downstream mediators of glucoprivic feeding was not supported. Although NPY/AGRP neurons were destroyed by NPY-SAP, the lesion did not impair either the feeding or the hyperglycemic response to 2-deoxy-D-glucose-induced blockade of glycolysis use. Similarly, responses to glucagon-like peptide-1 (GLP-1, 5 microg/3 microl icv), NPY (5 microg/3 microl icv), cholecystokinin octapeptide (4 microg/kg ip), and beta-mercaptoacetate (68 mg/kg ip) were not altered by the NPY-SAP lesion. Thus, NPY-SAP destroyed NPY receptor-expressing neurons in the ARC and selectively disrupted controls of feeding dependent on those neurons but did not disrupt peptidergic or metabolic controls dependent upon circuitry outside the BMH.


Assuntos
Hipotálamo/efeitos dos fármacos , Neuropeptídeo Y/farmacologia , Proteínas de Plantas/farmacologia , Proteína Relacionada com Agouti , Anfetaminas/metabolismo , Animais , Núcleo Arqueado do Hipotálamo/efeitos dos fármacos , Ligação Competitiva , Peso Corporal , Catecolaminas/metabolismo , Colecistocinina/metabolismo , Cocaína/farmacologia , Inibidores da Captação de Dopamina/farmacologia , Grelina , Glucagon/metabolismo , Peptídeo 1 Semelhante ao Glucagon , Imuno-Histoquímica , Hibridização In Situ , Concentração Inibidora 50 , Peptídeos e Proteínas de Sinalização Intercelular , Leptina/metabolismo , Ligantes , Masculino , Modelos Biológicos , Neurônios/metabolismo , Neuropeptídeo Y/metabolismo , Fragmentos de Peptídeos/metabolismo , Hormônios Peptídicos/metabolismo , Peptídeos/química , Pró-Opiomelanocortina/metabolismo , Ligação Proteica , Precursores de Proteínas/metabolismo , Proteínas/metabolismo , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Rombencéfalo/metabolismo , Tioglicolatos/metabolismo , Fatores de Tempo , Toxinas Biológicas/química , alfa-MSH/metabolismo
17.
Eur J Neurosci ; 19(8): 2147-54, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15090041

RESUMO

The hypothalamus is jointly innervated by hindbrain and hypothalamic neuropeptide Y (NPY) cell bodies. While the specific roles of these distinct sources of innervation are not known, NPY neurotransmission within the hypothalamus appears to contribute to glucoregulatory feeding. Here we examine the involvement of hindbrain NPY neurons in glucoregulation using in situ hybridization to assess their responsiveness to glucoprivation. The hindbrain NPY innervation of the hypothalamus is derived from cell bodies that coexpress norepinephrine or epinephrine. Therefore, we quantified NPY mRNA hybridization signal in hindbrain catecholamine cell groups 90 min after subcutaneous administration of the glycolytic inhibitor 2-deoxy-d-glucose (2DG, 250 mg/kg) to male rats. Catecholamine cell groups A1, A1/C1 and C2 (that provide the major NPY innervation of the hypothalamus) showed a basal level of NPY mRNA hybridization signal that was dramatically increased by 2DG. In C1 and C3, where basal NPY mRNA expression was close to or below our detection threshold, the hybridization signal was also significantly increased by 2DG. In cell groups A2, A5, A6 and A7, neither basal nor 2DG-stimulated NPY mRNA expression was detected. Hypothalamic microinjection of the retrogradely transported catecholamine immunotoxin saporin conjugated to anti-dopamine-beta-hydroxylase destroyed hindbrain catecholamine/NPY neurons and abolished basal and 2DG-stimulated increases in NPY expression in hindbrain cell groups. The responsiveness of hindbrain NPY neurons to glucose deficit suggests that these neurons participate in glucoprivic feeding or other glucoregulatory responses.


Assuntos
Hipotálamo/metabolismo , Neurônios/metabolismo , Neuropeptídeo Y/biossíntese , RNA Mensageiro/biossíntese , Rombencéfalo/metabolismo , Animais , Desoxiglucose/farmacologia , Regulação da Expressão Gênica/fisiologia , Glucose/antagonistas & inibidores , Glucose/metabolismo , Hipotálamo/efeitos dos fármacos , Masculino , Neurônios/efeitos dos fármacos , Neuropeptídeo Y/genética , RNA Mensageiro/genética , Ratos , Ratos Sprague-Dawley , Rombencéfalo/efeitos dos fármacos
18.
Neuroreport ; 13(8): 1041-5, 2002 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-12060805

RESUMO

Fibroblast growth factor (FGF)-1 modulates various brain functions, such as the hypothalamic control of feeding. In the rat, we examined the effect of intracerebroventricularly infused FGF-1 on the hypothalamic expression of tenascin-C, a selective mediator of neuron-glial interaction. In situ hybridization revealed little tenascin-C mRNA expression in control brains, but greatly increased expression in ependymal cells around the third ventricle in the FGF-1-infused rats. Reverse transcription-linked PCR analysis of hypothalamic mRNA revealed an FGF-1-induced expression not of the shortest isoform of tenascin-C, but of the long isoforms (with additional fibronectin type III-domain insertions). Quantitative analysis by real time PCR revealed that this induction was transient and dose-dependent. Specific modulation of hypothalamic neuron-glial interactions by tenascin-C may mediate FGF-1-induced feeding suppression.


Assuntos
Comunicação Celular/fisiologia , Epêndima/metabolismo , Fator 1 de Crescimento de Fibroblastos/metabolismo , Hipotálamo/metabolismo , Neuroglia/metabolismo , Neurônios/metabolismo , Tenascina/genética , Animais , Regulação do Apetite/efeitos dos fármacos , Regulação do Apetite/fisiologia , Comunicação Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Epêndima/citologia , Epêndima/efeitos dos fármacos , Fator 1 de Crescimento de Fibroblastos/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/fisiologia , Hipotálamo/citologia , Hipotálamo/efeitos dos fármacos , Masculino , Neuroglia/citologia , Neuroglia/efeitos dos fármacos , Neurônios/citologia , Neurônios/efeitos dos fármacos , Osteonectina/genética , Isoformas de Proteínas/genética , RNA Mensageiro/efeitos dos fármacos , RNA Mensageiro/metabolismo , Ratos , Ratos Wistar , Trombospondina 1/genética , Fatores de Tempo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA