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Efeito do protocolo de estressores e da privação de água sobre o consumo de sacarose, o peso corporal e o consumo de alimento e água em ratos; Effects of a stress protocol and water deprivation on sucrose consumption, body weight and food and water intake by rats

Pereira, Clarissa Moreira
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 17/04/2015 Português
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O Chronic Mild Stress (CMS) é um modelo animal de depressão estudado para investigação das causas e dos atenuadores deste problema. Nele, ratos são submetidos a um protocolo de estressores moderadamente aversivos de maneira crônica. É observada diminuição na ingestão e preferência por substância líquida doce por conta desta submissão. Em estudo sobre o papel da privação de alimento e água no conjunto de estressores, Pereira e Sério (2010) não observaram os efeitos de diminuição na ingestão e preferência por sacarose. É levantada a possibilidade de que a privação de água e alimento a que os sujeitos foram submetidos previamente ao protocolo poderia ter sido responsável pelas diferenças encontradas, já que diferiu em muitos aspectos do realizado por Willner et al. (1987). O objetivo do presente estudo foi o de investigar o papel da privação de água no protocolo de estressores. Três grupos de sujeitos foram propostos: Grupo Protocolo (submetido ao protocolo completo), Grupo Privação (submetido apenas à privação de água presente no protocolo) e Grupo Controle (submetido apenas aos testes semanais de ingestão e preferência). Foram realizados testes de ingestão e preferência por sacarose antes...

Baclofen into the lateral parabrachial nucleus induces hypertonic sodium chloride and sucrose intake in rats

De Oliveira, L. B.; Kimura, E. H.; Callera, J. C.; De Luca, L. A.; Colombari, D. S. A.; Menani, Jose Vanderlei
Fonte: Pergamon-Elsevier B.V. Ltd Publicador: Pergamon-Elsevier B.V. Ltd
Tipo: Artigo de Revista Científica Formato: 160-170
Português
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); GABA(A) and GABA(B) receptors are present in the lateral parabrachial nucleus (LPBN), a pontine area involved with inhibitory mechanisms related to the control of sodium appetite. Activation of GABA(A) receptors in the LPBN induces strong ingestion of 0.3 M sodium chloride (NaCl) in normonatremic and euhydrated rats. In the present study, we investigated the effects of the GABA(B) receptor agonist baclofen, injected alone or combined with GABA(A) or GABA(B) receptor antagonists into the LPBN on 0.3 M NaCl, water, 0.06 M sucrose and food intake in normonatremic and euhydrated rats. Male Holtzman rats with stainless steel cannulas implanted bilaterally in the LPBN were used. In normonatremic and euhydrated rats, bilateral injections of baclofen (0.5 nmol/0.2 mu l) into the LPBN induced 0.3 M NaCl (24.0 +/- 3.1 vs. saline: 2.0 +/- 0.8 ml/240 min) and water intake (10.6 +/- 1.4 vs. saline: 3.5 +/- 0.7 ml/240 min) in a two-bottle test. Injections of GABA(B) receptor antagonists CGP 35348 (50 nmol/0.2 mu l) or 2-hydroxysaclofen (5 nmol/0.2 mu l) or GABA(A) receptor antagonist bicuculline (1.6 nmo1/0.2 mu l) into the LPBN reduced 0.3 M NaCl (14.1 +/- 4.7 ml/240 min; 9.97 +/- 2.5 ml/210 min; 8.8 +/- 5.9 ml/240 min...

Increased susceptibility to development of anhedonia in rats with chronic peripheral nerve injury: Involvement of sleep deprivation?

Andersen, Monica L.; Hoshino, Katsumasa; Tufik, Sergio
Fonte: Pergamon-Elsevier B.V. Ltd Publicador: Pergamon-Elsevier B.V. Ltd
Tipo: Artigo de Revista Científica Formato: 960-966
Português
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Processo FAPESP: 98/14303-3; The Main purpose of the present study was to evaluate whether REM sleep deprivation (RSD) influences the development of anhedonia in rats in a peripheral neuropathy model induced by sciatic nerve constriction injury (CCI). Anhedonia was measured by assessing daily water/sucrose intake. Four groups were assessed: control (CTRL), CCI, RSD, and CCI + RSD (n = 8/group). Intake data were collected at baseline (mean of 3 days), on the 1st and 2nd days after a CCI or SHAM procedure, during 4 days of RSD, and during an additional 10 days (rebound period or equivalent in home-cage rats). Control rats spontaneously and progressively increased Sucrose intake, reaching final daily volumes significantly greater than respective initial baseline amounts. RSD promoted an additional and immediate significant increase in sucrose intake during sleep deprivation days. The CCI group did not display a spontaneous, progressive increase in sucrose intake. When CO was combined with RSD, the increase in sucrose intake induced by RSD was significantly lower than in animals submitted to RSD alone; the (CCI + RSD) group also failed to show a spontaneous and progressive increase in sucrose intake. The present findings indicate that animal model of chronic neuropathy exhibits reduced sucrose ingestion. Accordingly...

Conjugated linoleic acid and cardiac health: Oxidative stress and energetic metabolism in standard and sucrose-rich diets

Diniz, Yeda S.; Santos, Priscila P.; Assalin, Heloisa B.; Souza, Gisele A.; Rocha, Katiucha K. H. R.; Ebaid, Geovana Xavier; Seiva, Fabio R. F.; Amauchi, Juliana F.; Novelli Filho, Jose Luiz V. B.; Novelli, Ethel L. B.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 318-325
Português
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Studies on conjugated linoleic acid ingestion and its effect on cardiac tissue are necessary for the safe utilization of this compound as supplement for weight loss. Male Wistar 24-rats were divided into four groups (n = 6):(C)given standard chow, water and 0.5 ml saline, twice a week by gavage; (C-CLA)receiving standard chow, water and 0.5 ml of conjugated linoleic acid, twice a week, by gavage; (S)given standard chow, saline by gavage, and 30% sucrose in its drinking water; (S-CLA)receiving standard chow, 30% sucrose in its drinking water and conjugated linoleic acid. After 42 days of treatment S rats had obesity with increased abdominal-circumference, dyslipidemia, oxidative stress and myocardial lower citrate synthase(CS) and higher lactate dehydrogenase(LDH) activities than C. Conjugated linoleic acid had no effects on morphometric parameters in C-CLA, as compared to C, but normalized morphometric parameters comparing S-CLA with S. There was a negative correlation between abdominal adiposity and resting metabolic rate. Conjugated linoleic acid effect, enhancing fasting-VO2/surface area, postprandial-carbohydrate oxidation and serum lipid hydroperoxide resembled to that of the S group. Conjugated linoleic acid induced cardiac oxidative stress in both fed conditions...

Ingestion of saliva during carbohydrate feeding by Lutzomyia longipalpis (Diptera; Psychodidae)

Cavalcante,Reginaldo R; Pereira,Marcos H; Freitas,Jorge M; Gontijo,Nelder de F
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2006 Português
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The aim of this study was to obtain experimental evidence that phlebotomine saliva is actually ingested during the carbohydrate ingestion phase (before and after blood digestion). The ingestion of carbohydrate was simulated as it occurs in the field by offering the insects balls of cotton soaked in sucrose, sucrose crystals or orange juice cells. The results obtained here showed that ingestion occurred under each condition investigated, as indicated by the presence of apyrase, an enzyme used as a marker to detect saliva in the insect gut and/or carbohydrate sources. Saliva ingestion by phlebotomine during the carbohydrate ingestion phase is important to explain how it could promote starch digestion and to trigger Leishmania promastigotes to follow a differentiation pathway as proposed previously by some authors.

Sucrose ingestion causes opioid analgesia

Segato,F.N.; Castro-Souza,C.; Segato,E.N.; Morato,S.; Coimbra,N.C.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/1997 Português
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The intake of saccharin solutions for relatively long periods of time causes analgesia in rats, as measured in the hot-plate test, an experimental procedure involving supraspinal components. In order to investigate the effects of sweet substance intake on pain modulation using a different model, male albino Wistar rats weighing 180-200 g received either tap water or sucrose solutions (250 g/l) for 1 day or 14 days as their only source of liquid. Each rat consumed an average of 15.6 g sucrose/day. Their tail withdrawal latencies in the tail-flick test (probably a spinal reflex) were measured immediately before and after this treatment. An analgesia index was calculated from the withdrawal latencies before and after treatment. The indexes (mean ± SEM, N = 12) for the groups receiving tap water for 1 day or 14 days, and sucrose solution for 1 day or 14 days were 0.09 ± 0.04, 0.10 ± 0.05, 0.15 ± 0.08 and 0.49 ± 0.07, respectively. One-way ANOVA indicated a significant difference (F(3,47) = 9.521, P<0.001) and the Tukey multiple comparison test (P<0.05) showed that the analgesia index of the 14-day sucrose-treated animals differed from all other groups. Naloxone-treated rats (N = 7) receiving sucrose exhibited an analgesia index of 0.20 ± 0.10 while rats receiving only sucrose (N = 7) had an index of 0.68 ± 0.11 (t = 0.254...

Effect of sucrose ingestion on the performance of wild Anastrepha obliqua (Macquart) females (Diptera: Tephritidae)

Fontellas,Tânia M.L.; Zucoloto,Fernando S.
Fonte: Sociedade Entomológica do Brasil Publicador: Sociedade Entomológica do Brasil
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2003 Português
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Carbohydrates are the main source of energy for insects and the lack of these nutrients in the diet can cause serious damage to the biology of these arthropods. In order to better understand the effect of sucrose on the performance and dietary selection of adult Anastrepha obliqua (Macquart), the following experiments were carried out: 1) effect of different amount of sucrose on diet ingestion, longevity and egg production; 2) dietary selection that contains different amounts of sucrose, and 3) discrimination threshold for sucrose in adult individuals deprived or not of carbohydrates. The control diet showed the best results in relation to ingestion, longevity and egg production for these species, probably due to the fact that it presents an optimal nutritional balance between sucrose and yeast. The control diet was also the preferred diet of females, indicating a positive correlation between the nutritional value of a diet and chemical perception by A. obliqua. Sucrose-deprived females were able to perceive lower carbohydrate quantity than non-deprived females. This characteristic might represent a biological advantage since it reduces the food foraging time for these insects.

Suckling and sucrose ingestion suppress persistent hyperalgesia and spinal Fos expression after forepaw inflammation in infant rats

Ren, K.; Blass, E. M.; Zhou, Q.-q.; Dubner, R.
Fonte: The National Academy of Sciences of the USA Publicador: The National Academy of Sciences of the USA
Tipo: Artigo de Revista Científica
Publicado em 18/02/1997 Português
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Sweet taste and nonnutritive suckling produce analgesia to transient noxious stimuli in infant rats and humans. The present study evaluated the pain-modulating effects of sucrose and suckling in a rat model of persistent pain and hyperalgesia that mimics the response to tissue injury in humans. Fore- and hindpaw withdrawal latencies from a 30° or 48°C brass stylus were determined in 10-day-old rats following paw inflammation induced by complete Freund’s adjuvant (CFA; 1:1 injected s.c. in a 0.01 ml volume). CFA markedly decreased escape latencies to both 48° and 30°C stimulation, thereby demonstrating thermal hyperalgesia and mechanical allodynia. The combination of nonnutritive suckling and sucrose (7.5%, 0.01–0.06 ml/min) infusion markedly increased escape latencies to forepaw stimulation in both CFA-treated and control rats. In contrast, intraoral sucrose and suckling did not increase hindpaw withdrawal latencies in either control or CFA-inflamed rats. The effect was specific to sweet taste because neither water nor isotonic saline infusion affected forepaw escape latencies. Parallel findings were obtained for CFA-induced Fos-like immunoreactivity (Fos-LI), a marker of neuronal activation. Fos-LI was selectively induced in cervical and lumbar regions ipsilateral to forepaw and hindpaw inflammation...

The effects of sympathectomy and dexamethasone in rats ingesting sucrose

Franco-Colín, Margarita; Villanueva, Iván; Piñón, Manuel; Racotta, Radu
Fonte: Ivyspring International Publisher Publicador: Ivyspring International Publisher
Tipo: Artigo de Revista Científica
Publicado em 04/03/2006 Português
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Both high-sucrose diet and dexamethasone (D) treatment increase plasma insulin and glucose levels and induce insulin resistance. We showed in a previous work (Franco-Colin, et al. Metabolism 2000; 49:1289-1294) that combining both protocols for 7 weeks induced less body weight gain in treated rats without affecting mean daily food intake. Since such an effect may be explained by an increase in caloric expenditure, possibly due to activation of the sympathetic nervous system by sucrose ingestion, in this work, and using 10% sucrose in the drinking water, male Wistar rats were divided into 4 groups. Two groups were sympathectomized using guanethidine (Gu) treatment for 3 weeks. One of these groups of rats received D in the drinking water. Of the 2 groups not receiving Gu, one was the control (C) and the other received D. After 8 weeks a glucose tolerance test was done. The rats were sacrificed and liver triglyceride (TG), perifemoral muscle lipid, and norepinephrine (NE) levels in the liver spleen, pancreas, and heart were determined. Gu-treated rats (Gu and Gu+D groups) showed less than 10% NE concentration compared to C and D rats, less daily caloric intake and body-weight gain, more sucrose intake, and better glucose tolerance. The area under the curve after glucose administration correlated significantly with the mean body weight gain of the rats...

Analgesia accompanying food consumption requires ingestion of hedonic foods

Foo, H.; Mason, Peggy
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 14/10/2009 Português
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Animals eat rather than react to moderate pain. Here, we examined the behavioral, hedonic, and neural requirements for ingestion analgesia in ad libitum fed rats. Noxious heat-evoked withdrawals were similarly suppressed during self-initiated chocolate-eating and ingestion of intraorally infused water, sucrose, or saccharin, demonstrating that ingestion analgesia does not require feeding motivation, self-initiated food procurement, sucrose or calories. Rather, food hedonics is important since neither salt ingestion nor quinine rejection elicited analgesia. During quinine-induced nausea and lipopolysaccharide (LPS)-induced illness, conditions when chocolate-eating was presumably less pleasurable, analgesia accompanying chocolate consumption was attenuated. Yet, analgesia during water ingestion was preserved in LPS-injected rats who showed enhanced palatability for water within this context. The dependence of ingestion analgesia on the positive hedonics of an ingestate was confirmed in rats with a conditioned taste aversion to sucrose: after paired exposure to sucrose and LPS, rats no longer showed analgesia during sucrose ingestion but continued to show analgesia during chocolate consumption. Eating pauses tended to occur less often and for shorter durations in the presence of ingestion analgesia than in its absence. Therefore...

Eucalyptus Leaf Extract Suppresses the Postprandial Elevation of Portal, Cardiac and Peripheral Fructose Concentrations after Sucrose Ingestion in Rats

Sugimoto, Keiichiro; Hosotani, Tetsuro; Kawasaki, Takahiro; Nakagawa, Kazuya; Hayashi, Shuichi; Nakano, Yoshihisa; Inui, Hiroshi; Yamanouchi, Toshikazu
Fonte: the Society for Free Radical Research Japan Publicador: the Society for Free Radical Research Japan
Tipo: Artigo de Revista Científica
Português
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Overintake of sucrose or fructose induces adiposity. Fructose undergoes a strong Maillard reaction, which worsens diabetic complications. To determine whether Eucalyptus globulus leaf extract (ELE) suppresses the postprandial elevation of serum fructose concentrations (SFCs) in the portal, cardiac, and peripheral blood after sucrose ingestion, we performed gas chromatography/mass spectrometry (GC/MS) and measured SFC without any interference by contaminating glucose in the samples. Fasting Wistar rats were orally administered water (control group) or ELE (ELE group) before sucrose ingestion. Blood was collected from the portal vein, heart, and tail. The increase in the SFCs in the portal and cardiac samples 30 min after sucrose ingestion was lower in the ELE group than in the control group. The coefficient of correlation between the SFCs in the portal and cardiac samples was 0.825. The peripheral SFC in the control group progressively increased and was 146 µmol/L at 60 min. This increase was significantly lower in the ELE group. In contrast, the serum glucose concentrations in the 2 groups were similar. ELE suppressed postprandial hyperfructosemia in the portal, cardiac, and peripheral circulations. ELE may counteract glycation caused by high blood fructose concentrations induced by the consumption of fructose-containing foods or drinks.

Amygdala response to sucrose consumption is inversely related to artificial sweetener use

Rudenga, KJ; Small, DM
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Português
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Controversy exists over whether exposure to artificial sweeteners degrades the predictive relationship between sweet taste and its post-ingestive consequences. Here we tested whether brain response to caloric sucrose is influenced by individual differences in self-reported artificial sweetener use. Twenty-six subjects participated in fMRI scanning while consuming sucrose solutions. A negative correlation between artificial sweetener use and amygdala response to sucrose ingestion was observed. This finding supports the hypothesis that artificial sweetener use may be associated with brain changes that could influence eating behavior.

Parabrachial coding of sapid sucrose: Relevance to reward and obesity

Hajnal, Andras; Norgren, Ralph; Kovacs, Peter
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/2009 Português
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Cumulative evidence in rats suggests that the pontine parabrachial nucleus (PBN) is necessary for assigning hedonic value to taste stimuli. In a series of studies, our laboratory has investigated the parabrachial coding of sapid sucrose in normal and obese rats. First, using chronic microdialysis, we demonstrated that sucrose intake increases dopamine release in the nucleus accumbens, an effect that is dependent on oral stimulation and on concentration. The dopamine response was independent of the thalamocortical gustatory system, but was blunted substantially by lesions of the PBN. Similar lesions of the PBN but not the thalamic taste relay diminished cFos activation by sucrose ingestion in the nucleus accumbens. Recent single neuron recording studies demonstrated that processing of sucrose-evoked activity in the PBN is altered in the Otsuka Long Evans Tokushima Fatty (OLETF) rats that develop obesity due to chronic overeating and express increased avidity to sweet. Compared with lean controls, taste neurons in OLETF rats had reduced overall sensitivity to sucrose and altered concentration responses: decreased responses to lower and augmented responses to higher concentrations. The decreased sensitivity to sucrose was specific to NaCl-best neurons that also responded to sucrose...

Oxytocin action in the ventral tegmental area affects sucrose intake

Mullis, Kiersten; Kay, Kristen; Williams, Diana L.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Português
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Brain oxytocin is known to play a role in the control of food intake, and recent studies suggest that stimulation of central oxytocin receptors selectively suppresses carbohydrate intake. The specific oxytocin projection sites and receptor populations involved in this response are as yet unidentified. We hypothesized that oxytocin receptors in the ventral tegmental area (VTA) may play a role in limiting sucrose intake, because the VTA is known to influence palatable food intake. We first performed a dose response study in which we observed that intra-VTA oxytocin injection significantly suppressed intake of a 10% sucrose solution during a 30-min test session by 13.35% - 20.5% relative to vehicle treatment. Doses of intra-VTA oxytocin that suppressed sucrose intake had no effect on water intake. Next we examined the effects of two oxytocin receptor antagonists, (d(CH2)51,Tyr(Me)2,Orn8)-Oxytocin (OVT) and L-368,899. Each of these antagonists significantly increased 10% sucrose intake by 17% - 20.5% relative to vehicle when delivered directly into the VTA, at doses subthreshold for effect if injected into the cerebral ventricles. Finally, we observed that the effect of intra-VTA oxytocin to suppress 10% sucrose intake was significantly attenuated by pretreatment with L-368...

Sucrose Ingestion Induces Rapid AMPA Receptor Trafficking

Tukey, David S.; Ferreira, Jainne M.; Antoine, Shannon O.; D’amour, James A.; Ninan, Ipe; de Vaca, Soledad Cabeza; Incontro, Salvatore; Wincott, Charlotte; Horwitz, Julian K.; Hartner, Diana T.; Guarini, Carlo B.; Khatri, Latika; Goffer, Yossef; Xu, Duo
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 03/04/2013 Português
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The mechanisms by which natural rewards such as sugar affect synaptic transmission and behavior are largely unexplored. Here, we investigate regulation of nucleus accumbens synapses by sucrose intake. Previous studies have shown that AMPA receptor trafficking is a major mechanism for regulating synaptic strength, and that in vitro, trafficking of AMPA receptors containing the GluA1 subunit takes place by a two-step mechanism involving extrasynaptic and then synaptic receptor transport. We report that in rat, repeated daily ingestion of a 25% sucrose solution transiently elevated spontaneous locomotion and potentiated accumbens core synapses through incorporation of Ca2+-permeable AMPA receptors (CPARs), which are GluA1-containing, GluA2-lacking AMPA receptors. Electrophysiological, biochemical and quantitative electron microscopy studies revealed that sucrose training (7 days) induced a stable (>24 hr) intraspinous GluA1 population, and that in these rats a single sucrose stimulus rapidly (5 min) but transiently (<24 hr) elevated GluA1 at extrasynaptic sites. CPARs and dopamine D1 receptors were required in vivo for elevated locomotion after sucrose ingestion. Significantly, a 7-day protocol of daily ingestion of a 3% solution of saccharin...

Avocado Oil Supplementation Modifies Cardiovascular Risk Profile Markers in a Rat Model of Sucrose-Induced Metabolic Changes

Carvajal-Zarrabal, Octavio; Nolasco-Hipolito, Cirilo; Aguilar-Uscanga, M. Guadalupe; Melo-Santiesteban, Guadalupe; Hayward-Jones, Patricia M.; Barradas-Dermitz, Dulce M.
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
Português
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The purpose of this study was to evaluate the effects of avocado oil administration on biochemical markers of cardiovascular risk profile in rats with metabolic changes induced by sucrose ingestion. Twenty-five rats were divided into five groups: a control group (CG; basic diet), a sick group (MC; basic diet plus 30% sucrose solution), and three other groups (MCao, MCac, and MCas; basic diet plus 30% sucrose solution plus olive oil and avocado oil extracted by centrifugation or using solvent, resp.). Glucose, total cholesterol, triglycerides, phospholipids, low- and high-density lipoproteins (LDL, HDL), very low-density lipoprotein (VLDL), lactic dehydrogenase, creatine kinase, and high sensitivity C-reactive protein concentration were analyzed. Avocado oil reduces TG, VLDL, and LDL levels, in the LDL case significantly so, without affecting HDL levels. An effect was exhibited by avocado oil similar to olive oil, with no significant difference between avocado oil extracted either by centrifugation or solvent in myocardial injury biochemical indicators. Avocado oil decreased hs-CRP levels, indicating that inflammatory processes were partially reversed. These findings suggested that avocado oil supplementation has a positive health outcome because it reduces inflammatory events and produces positive changes in the biochemical indicators studied...

mTOR hyperactivity mediates the detrimental effects of a high sucrose diet on Alzheimer’s disease pathology

Orr, Miranda E.; Salinas, Angelica; Buffenstein, Rochelle; Oddo, Salvatore
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Português
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High sugar consumption and diabetes increase the risk of developing Alzheimer’s disease (AD) by unknown mechanisms. Using an animal model of AD, here we show that high sucrose intake induces obesity with changes in central and peripheral insulin signaling. These pre-diabetic changes are associated with an increase in Aβ production and deposition. Moreover, high sucrose ingestion exacerbates tau phosphorylation by increasing Cdk5 activity. Mechanistically, the sucrose-mediated increase in AD-like pathology is due to hyperactive mTOR, a key nutrient sensor important in regulating energy homeostasis. Specifically, we show that rapamycin, an mTOR inhibitor, prevents the detrimental effects of sucrose in the brain without altering changes in peripheral insulin resistance. Overall, our data suggest that high sucrose intake and dysregulated insulin signaling, which are known to contribute to the occurrence of diabetes, increase the risk of developing AD by upregulating mTOR signaling. Therefore, early interventions to modulate mTOR activity in individuals at high risk of developing diabetes may decrease their AD susceptibility.

The effects of drinks made from simple sugars on blood pressure in healthy older people

Visvanathan, R.; Chen, R.; Garcia, M.; Horowitz, M.; Chapman, I.
Fonte: C A B I Publishing Publicador: C A B I Publishing
Tipo: Artigo de Revista Científica
Publicado em //2005 Português
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The objective of the research was to determine the blood pressure (BP) lowering effects in older people of 50 g carbohydrate drinks with varying carbohydrate content using a randomised, cross-over study with ten (six females) healthy older subjects (mean age 72·20 (SEM 1·50) years). BP, heart rate and glucometer-derived blood glucose levels were determined at baseline and following the ingestion of equal volumes (300 ml) of water and carbohydrate drinks with varying nutrient content (glucose, sucrose and fructose). A significant decline in BP over the first 60 min was seen following glucose (systolic BP (SBP) P,0·01, diastolic BP (DBP) P,0·01, mean arterial BP (MAP) P¼0·03) and sucrose (SBP P,0·01, DBP P,0·01, MAP P,0·01) ingestion, although the decrease occurred earlier after glucose than sucrose ingestion (SBP 7·33 (SEM 2·19) v. 21·00 (SEM 4·30) min (P¼0·03) and MAP 11·22 (SEM 3·10) v. 17·00 (SEM 3·78) min (P¼0·03)). BP increased after water ingestion (SBP P¼0·04, DBP P¼0·18, MAP P¼0·02) but did not change after fructose ingestion (SBP P¼0·36, DBP P¼0·81, MAP P¼0·34). Post hoc analyses revealed that the BP (SBP, DBP and MAP) decrease following glucose and sucrose ingestion were similar but significantly greater than following fructose or water ingestion. Sucrose...

Oral ingestion of Streptococcus thermophilus diminishes severity of small intestinal mucositis in methotrexate treated rats

Tooley, K.; Howarth, G.; Lymn, K.; Lawrence, A.; Butler, R.
Fonte: Landes Bioscience Publicador: Landes Bioscience
Tipo: Artigo de Revista Científica
Publicado em //2006 Português
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Background: Currently, there are no available effective preventative or adjunctive agents to alleviate symptoms of chemotherapy-induced mucositis. This is compounded by the absence of a recognized and validated non-invasive biomarker to assess gut function. This study investigated the effects of orally ingested Streptococcus thermophilus (TH-4) on chemotherapy-induced small intestinal damage in rats using the non-invasive 13C-sucrose breath test (SBT). Methods: Gastrointestinal damage was induced in 27 female dark agouti rats (148 ± 1g) with MTX (1.5 mg/kg; i.m.). Rats received MTX or saline at 0 h; with daily treatment of: TH-4 at doses of 109 (high), 108 (low) cfu/mL, or skim milk (vehicle), 48 h pre and 96 h post-MTX. The non-invasive 13C-sucrose breath test (SBT) was conducted at -24, 24 and 96 h post-MTX to monitor gut function. At sacrifice, small intestinal tissues were collected for determinations of sucrase activity, myeloperoxidase (MPO) activity and histological assessment. Results: MTX + vehicle and MTX + low TH-4-treated rats produced significantly lower SBT and sucrase activity results compared to saline controls (p < 0.001). In contrast, MTX + high TH-4 treatment showed no significant differences in the SBT compared to saline controls...

Modulación del comportamiento alimentario en hormigas: fisiología de la ingestión de néctar; Feeding behaviour modultion in ants: physiology of nectar ingestion

Falibene, Agustina L.
Fonte: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires Publicador: Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires
Tipo: info:eu-repo/semantics/doctoralThesis; tesis doctoral; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Publicado em //2012 Português
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La alimentación es un comportamiento complejo cuya regulación involucra la integración de factores externos e internos. En insectos sociales este comportamiento no solo varía de acuerdo a las características del alimento y las condiciones ambientales sino que también de acuerdo a los requerimientos de la colonia. En este trabajo combinamos estudios de comportamiento, electrofisiológicos, farmacológicos e inmunocitoquímicos para estudiar cómo distintos factores afectan la ingestión de soluciones azucaradas en la hormiga Camponotus mus. Nuestros estudios mostraron que el ayuno de la colonia determina la motivación recolectora de la hormiga forrajera modificando la concentración umbral de aceptación y su comportamiento de ingestión no solo de soluciones azucaradas sino también de cebos tóxicos. Durante la ingestión, el accionar de la bomba de succión estuvo determinado por el ayuno de la colonia, la temperatura ambiental, la concentración de sacarosa y la presencia de tóxico en la solución. Cambios en estas variables dieron lugar a variaciones en la velocidad y el tiempo de ingestión a través de la modulación de la frecuencia de bombeo, el volumen de solución incorporado por cada bombeo o el número de bombeos totales. Indagamos sobre los mecanismos neuroendócrinos involucrados y encontramos un efecto depresivo de la serotonina sobre la ingestión. También observamos la presencia de neuronas serotoninérgicas en los centros nerviosos involucrados en el control de la alimentación e inervaciones serotoninérgicas a lo largo del tubo digestivo. En conjunto...