Inhibitory effect of DUP-753 on the drinking responses of rats to central administration of noradrenaline and angiotensin II and to dehydration

We investigated the effect of losartan (DUP-753) on the dipsogenic responses produced by intracerebroventricular (icv) injection of noradrenaline (40 nmol/mu l) and angiotensin II (ANG II) (2 ng/mu l) in male Holtzman rats weighing 250-300 g. The effect of DUP-753 was also studied in animals submitted to water deprivation for 30 h. After control injections of isotonic saline (0.15 M NaCl, 1 mu l) into the lateral ventricle (LV) the water intake was 0.2 +/- 0.01 ml/h. DUP-753 (50 nmol/mu l) when injected alone into the LV of satiated animals had no significant effect on drinking (0.4 +/- 0.02 ml/h) (N = 8). DUP-753 (50 nmol/mu l) injected into the LV prior to noradrenaline reduced the water intake from 2.4 +/- 0.8 to 0.8 +/- 0.2 ml/h (N = 8). The water intake induced by injection of ANG II and water deprivation was also reduced from 9.2 +/- 1.4 and 12.7 +/- 1.4 ml/h to 0.8 +/- 0.2 and 1.7 +/- 0.3 ml/h (N = 6 and N = 8), respectively. These data indicate a correlation between noradrenergic pathways and angiotensinergic receptors and lead us to conclude that noradrenaline-induced water intake may be due to the release of ANG II by the brain. The finding that water intake was reduced by DUP-753 in water-deprived animals suggests that dehydration releases ANG II, and that AT(1) receptors of the brain play an important role in the regulation of water intake induced by deprivation.

Thermal decomposition and rehydration of strontium oxalate: morphological evolution

Undoped and Eu3+ doped monohydrate strontium oxalate samples were precipitated under ultrasound and conventional stirring and were heated at different temperatures. All samples were characterized by X-ray powder diffraction (XDR), infrared spectra (IR) and scanning electron microscopy (SEM). Monohydrate, dehydrate oxalates and carbonate particles are ellipsoids indicating a topotatic process. Particle size decrease is observed when ultrasound stirring and europium. doping are used and rehydration of strontium oxalate results in uniform hexagonal particle shape. An oxide and carbonate mixture is obtained from oxalates treated at 1050 degreesC and its suspension in water undergoes incomplete hydrolysis. The products from this incomplete hydrolysis present dendrite shape particles only when the former is precipitated under ultrasound stirring. In this process, surface energy is important for particle dispersion and ultrasound supplies activation energy to oxalate precursor. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

Potassium intake during cell dehydration

Isotonic NaCl is ingested in addition to water by cell-dehydrated rats in two-bottle tests. The objective of the present work was to find out whether mineral intake in the cell-dehydrated rat is specific to NaCl in a five-bottle test. Adult male Sprague Dawley rats had distilled water and four mineral solutions at palatable concentrations (0.01 M KCl, 0.05 mM CaCl2, 0.15 M NaHCO3, 0.15 M NaCl) simultaneously available for consumption. Cell-debydration was produced infusing 1.5 ml of NaCl solution (0.15, 0.25, 0.5, 1.01, 2.0, 4.0 M) intravenously for 10 min and intakes were recorded for the next hour. It was observed a NaCl concentration-dependent increase in 0.01 M KCl intake. The ingestion of the other mineral solutions was not significantly altered compared to infusion of 0.15 M NaCl. The ingestion of KCl was not related to changes in serum potassium concentration. The ingestion of KCl was reduced in half and water was the preferred fluid when the five-bottle test was performed with mineral solutions at isomolar (0.15 M) concentrations. There was no increase in intake of other mineral solution in the isomolar test. No preference was observed for palatable or isomolar solutions during early extracellular dehydration until 4 h after subcutaneous injection of furosemide, in spite of the increase in total volume intake. Therefore, mineral intake induced by cell dehydration is not specific for NaCl solution. The type of mineral solution available influences the choice and KCl. is the preferred solution of the cell-dehydrated rat in the conditions of the present study. (c) 2005 Elsevier B.V. All rights reserved.

Interaction between the lateral preoptic area and the subfornical organ in the control of water ingestion caused by cellular dehydration, hypotension, hypovolemia, and deprivation

Water intake was studied in albino rats with lesions in the lateral preoptic area, in the subfornical organ, and in both the lateral preoptic area and the subfornical organ. Drinking was induced by cellular dehydration, hypovolemia, hypotension (isoproterenol or caval ligation), and water deprivation. The animals with lesions in both areas showed a significant reduction in their water intake in response to cellular dehydration. Drinking due to extracellular dehydration was reduced in the animals that received only subfornical organ lesions, and was reduced even further in the animals with both areas ablated. The lesions in the subfornical organ were sufficient to reduce the thirst induced by caval ligation. The lesions in both areas inhibit water intake induced by caval ligation. Water intake induced by deprivation was reduced when both areas were destroyed. These findings demonstrate that both the lateral preoptic area and the subfornical organ are necessary for normal drinking in response to cellular dehydration, hypovolemia, and hypotension. There is further evidence that the lateral preoptic area and subfornical organ interact in the control of water intake induced by a variety of thirst challenges.

Osmotic Dehydration of Pineapple with Impregnation of Sucrose, Calcium, and Ascorbic Acid

Mass transfer was evaluated during osmotic dehydration of pineapple in solutions with until four components aiming to investigate the solutes concentration influence on impregnation. In the first step, the experimental trials for optimization of solution concentration were based on 23 factorial design. In the second step, effective diffusion coefficients were determined. Equations representing the influence of the concentration of sucrose, calcium lactate, and ascorbic acid in osmotic solutions on water loss and gains of sucrose, calcium, and vitamin C were found. Results showed that both calcium lactate and sucrose concentration affected calcium and sucrose gain. On the other hand, only vitamin C gain was significantly affected by the ascorbic acid concentration in the studied concentration range. However, when comparing diffusivities in pineapple immersed in sucrose solutions, with and without calcium lactate, with and without ascorbic acid, it was possible to verify that diffusivities of water, sugar, and calcium increased in presence of ascorbic acid in solution. Calcium in solution diminished the water and sucrose diffusivities. High calcium and vitamin C contents were obtained in 1 h immersion in the solutions studied. © 2013 Springer Science+Business Media New York.

A comparative study of glycerol dehydration catalyzed by micro/mesoporous MFI zeolites

The catalytic properties of monomodal microporous and bimodal micro-mesoporous zeolites were investigated in the gas-phase dehydration of glycerol. The desilication methodology used to produce the mesoporous zeolites minimized diffusion limitations and increased glycerol conversion in the catalytic reaction due to the hierarchical system of secondary pores created in the zeolite crystals. The chemical and structural properties of the catalyst were studied by X-ray diffraction, nitrogen adsorption-desorption isotherms, NH3-TPD and pyridine chemisorption followed by IR-spectroscopy. Although the aim was to desilicate to create mesoporosity in the zeolite crystals, the desilication promoted the formation of extra-framework aluminum species that affected the conversion of glycerol and the products distribution. The results clearly show that the mesoporous zeolites with designed mesopore structure allowed a rapid diffusion and consequently improved the reaction kinetics. However, especial attention must be given to the desilication procedure because the severity of the treatment negatively interfered on the Brønsted and Lewis acid sites relative concentration and, consequently, in the efficiency of the catalysis performed by these materials. On the other hand, during the catalytic reaction, the intracrystalline mesopores allowed carbonaceous compounds to be deposited herein, resulting in less blocked micropores and catalysts with higher long-term stability.

Baclofen into the lateral parabrachial nucleus induces hypertonic sodium chloride intake during cell dehydration

Background: Activation of GABAB receptors with baclofen into the lateral parabrachial nucleus (LPBN) induces ingestion of water and 0.3 M NaCl in fluid replete rats. However, up to now, no study has investigated the effects of baclofen injected alone or combined with GABAB receptor antagonist into the LPBN on water and 0.3 M NaCl intake in rats with increased plasma osmolarity (rats treated with an intragastric load of 2 M NaCl). Male Wistar rats with stainless steel cannulas implanted bilaterally into the LPBN were used.Results: In fluid replete rats, baclofen (0.5 nmol/0.2 μl), bilaterally injected into the LPBN, induced ingestion of 0.3 M NaCl (14.3 ± 4.1 vs. saline: 0.2 ± 0.2 ml/210 min) and water (7.1 ± 2.9 vs. saline: 0.6 ± 0.5 ml/210 min). In cell-dehydrated rats, bilateral injections of baclofen (0.5 and 1.0 nmol/0.2 μl) into the LPBN induced an increase of 0.3 M NaCl intake (15.6 ± 5.7 and 21.5 ± 3.5 ml/210 min, respectively, vs. saline: 1.7 ± 0.8 ml/210 min) and an early inhibition of water intake (3.5 ± 1.4 and 6.7 ± 2.1 ml/150 min, respectively, vs. saline: 9.2 ± 1.4 ml/150 min). The pretreatment of the LPBN with 2-hydroxysaclofen (GABAB antagonist, 5 nmol/0.2 μl) potentiated the effect of baclofen on 0.3 M NaCl intake in the first 90 min of test and did not modify the inhibition of water intake induced by baclofen in cell-dehydrated rats. Baclofen injected into the LPBN did not affect blood pressure and heart rate.Conclusions: Thus, injection of baclofen into the LPBN in cell-dehydrated rats induced ingestion of 0.3 M NaCl and inhibition of water intake, suggesting that even in a hyperosmotic situation, the blockade of LPBN inhibitory mechanisms with baclofen is enough to drive rats to drink hypertonic NaCl, an effect independent of changes in blood pressure. © 2013 Kimura et al.; licensee BioMed Central Ltd.

Efeito das condições de congelamento sobre atributos de qualidade de fatias de abacaxi liofilizado

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito da velocidade de congelamento sobre a liofilização, reidratação e atributos de qualidade de fatias de maçã

Pós-graduação em Engenharia e Ciência de Alimentos - IBILCE

Balanço híbrido e desempenho locomotor em esécies de anuros de mata atlântica e cerrado

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of calcium on the osmotic dehydration kinetics and quality of pineapple

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Rehydration of corn grain with acid whey improves the silage quality

Our objective was to investigate the effects of rehydration with acid whey or water at three moisture levels, as well as the effects of bacterial inoculation, on the fermentation, chemical composition and aerobic stability of corn grain silages. The trial was conducted in a completely randomized design with four replicates in a factorial arrangement as follows: 3 (rehydration with three different moisture levels: 300,350 and 400 mL/kg of corn grain)x 2 (silage inoculated with bacteria or not inoculated (control))x 2 (liquid used in the rehydration: acid whey or water). Overall, corn grain silages rehydrated with acid whey produced more lactic acid than the silages rehydrated with water (13.8 vs. 12.6 g/kg of dry matter (DM), respectively). In addition, increases in the rehydration of corn grain silages promoted decreases (linear) in lactic acid concentration as well as in production of total acids. Although inoculated silages had higher pH as consequence of the rehydration using water at the three levels, these treatments presented high DM recovery. In general, neutral detergent fiber (aNDFom) decreased if inoculant was applied in corn grain silages rehydrated with acid whey. After silos opening, silages rehydrated with 350 or 400 mL/kg (independent of the liquid) had lower aerobic stability than silages rehydrated with 300 mL/kg. Overall, we found that the inoculant did not promote significant changes in the composition of the corn grain silage. In contrast, the potential of the use of acid whey in ensiling corn grain is high, as its addition leads to improvements in the fermentation process and aerobic stability of the silages. (C) 2014 Elsevier B.V. All rights reserved.

Osmotic dehydration of mango with ascorbic acid impregnation: influence of process variables

The present study investigated the osmotic dehydration (OD) of mangoes cv.Palmer, dehydrated in a sucrose solution with added ascorbic acid (AA), aiming toevaluate the influence of the process variables (sucrose concentration, AA concen-tration and time) on vitamin C, water, sugars and total phenolic compound (TPC)contents by way of an analysis of the effects and the variance of the factors. Thesucrose concentration did not affect the vitamin C content, but the AA concentra-tion in the solution and the process time exerted a positive influence on thisresponse. The addition of AA also presented a significant positive effect on theTPC contents because this vitamin interferes with the quantification of the TPC.On discounting the interferences, no losses of phenolic compounds were found.Impregnation with vitamin C during OD was shown to be effective in obtainingminimally processed mangoes with high nutritional value.