Involvement of the mesolimbic system in palatability-induced ingestion.
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Animals↗
Biomedical subjects
Tohru Fushiki
Publications and source records attributed to Tohru Fushiki.
(-)-Hydroxycitrate ingestion and endurance exercise performance.
We have been interested in the ergogenic aid effects of food components and supplements for enhancing endurance exercise performance. For this purpose, acute or chronic (-)-hydroxycitrate (HCA) ingestion might be effective because it promotes utilization of fatty acid as an energy source. HCA is a competitive inhibitor of the enzyme ATP: citrate lyase, thereby increasing inhibition of lipogenesis in the body. Many researchers have reported that less body fat accumulation and sustained satiety cause less food intake. After focusing on exercise performance with HCA ingestion, we came up with different results that show positive effects or not. However, our previously reported data showed increased use of fatty acids during moderate intensity exercise. For future research, HCA and co-ingestion of other supplements, such as carnitine or caffeine, might have greater effect on glycogen-sparing than HCA alone.
ATP Citrate (pro-S)-Lyase↗
Sulfated polysaccharides derived from dietary seaweeds increase the esterase activity of a lymphocyte tryptase, granzyme A.
Intake of sulfated polysaccharides, such as fucoidan or lambda-carrageenan extracted from seaweeds, has been shown to enhance immune responses, resulting in inhibition of tumor growth. However, little is known about the mechanisms by which these sulfated compounds mediate the enhancement. In the present study, we examined the effect of sulfated polysaccharides from seaweeds on esterase activity of a lymphocyte tryptase, granzyme A (GzmA), which is believed to induce the production of cytokines in a variety of cells. Inclusion of fucoidan (from Fucus vesiculosus) or lambda-carrageenan (from Gigartina aciculaire and Gigartina) in the reaction mixture increased the hydrolysis of Nalpha-benzyloxy-L-lysine thiobenzyl ester (BLT) by a recombinant rat GzmA in a concentration-dependent manner. Heparin, a sulfated polysaccharide from animal tissues, also increase the BLT hydrolysis, but the effect was less remarkable than those of the polysaccharides from the seaweeds. Hanes-Woolf analysis revealed that the enhancements in the presence of these sulfated compounds from the seaweeds were attributed to the increases in the affinity of the enzyme toward the substrate but not to those in the turnover rate. Chondroitin sulfate A, a sulfated polysaccharide found in animal and plant tissues, showed no positive effect on the hydrolysis. In the present paper, we propose that the enhancement of immune responses by intake of the sulfated polysaccharides from seaweeds can be partially accounted for by their direct effects on GzmA.
Animals↗
Enhanced insulin sensitivity, energy expenditure and thermogenesis in adipose-specific Pten suppression in mice.
Pten is an important phosphatase, suppressing the phosphatidylinositol-3 kinase/Akt pathway. Here, we generated adipose-specific Pten-deficient (AdipoPten-KO) mice, using newly generated Acdc promoter-driven Cre transgenic mice. AdipoPten-KO mice showed lower body and adipose tissue weights despite hyperphagia and enhanced insulin sensitivity with induced phosphorylation of Akt in adipose tissue. AdipoPten-KO mice also showed marked hyperthermia and increased energy expenditure with induced mitochondriagenesis in adipose tissue, associated with marked reduction of p53, inactivation of Rb, phosphorylation of cyclic AMP response element binding protein (CREB) and increased expression of Ppargc1a, the gene that encodes peroxisome proliferative activated receptor gamma coactivator 1 alpha. Physiologically, adipose Pten mRNA decreased with exposure to cold and increased with obesity, which were linked to the mRNA alterations of mitochondriagenesis. Our results suggest that altered expression of adipose Pten could regulate insulin sensitivity and energy expenditure. Suppression of adipose Pten may become a beneficial strategy to treat type 2 diabetes and obesity.
Adiponectin↗
Capsaicin inhibits the production of tumor necrosis factor alpha by LPS-stimulated murine macrophages, RAW 264.7: a PPARgamma ligand-like action as a novel mechanism.
Capsaicin, a major ingredient of hot pepper, is considered to exhibit anti-inflammatory properties. Our previous study demonstrated that capsaicin inhibited the production of pro-inflammatory mediators through NF-kappaB inactivation in LPS-stimulated macrophages. In order to further clarify the mechanism underlying the anti-inflammatory action of capsaicin, we investigated whether capsaicin alters PPARgamma activity, which regulates the production of the pro-inflammatory cytokine TNFalpha. Capsaicin significantly inhibited the production of TNFalpha by macrophages in a dose-dependent manner. Simultaneous exposure of the cells to capsaicin and PPARgamma agonist troglitazone or RXR agonist LG100268 resulted in stronger inhibition of TNFalpha production compared to the cells treated with either capsaicin, troglitazone, or LG100268 alone. Luciferase reporter assay revealed that capsaicin induced GAL4/PPARgamma chimera and full length PPARgamma (PPRE) transactivations in a dose-dependent manner. Furthermore, a specific PPARgamma antagonist T0070907 abrogated the inhibitory action of capsaicin on LPS-induced TNFalpha production by RAW 264.7 cells, indicating that capsaicin acts like a ligand for PPARgamma. Our data demonstrate for the first time that the anti-inflammatory action of capsaicin may be mediated by PPARgamma activation in LPS-stimulated RAW 264.7 cells.
Animals↗
Possible involvement of the alpha1 isoform of 5'AMP-activated protein kinase in oxidative stress-stimulated glucose transport in skeletal muscle.
Recent studies have suggested that 5'AMP-activated protein kinase (AMPK) is activated in response to metabolic stresses, such as contraction, hypoxia, and the inhibition of oxidative phosphorylation, which leads to insulin-independent glucose transport in skeletal muscle. In the present study, we hypothesized that acute oxidative stress increases the rate of glucose transport via an AMPK-mediated mechanism. When rat epitrochlearis muscles were isolated and incubated in vitro in Krebs buffer containing the oxidative agent H(2)O(2), AMPKalpha1 activity increased in a time- and dose-dependent manner, whereas AMPKalpha2 activity remained unchanged. The activation of AMPKalpha1 was associated with phosphorylation of AMPK Thr(172), suggesting that an upstream kinase is involved in the activation process. H(2)O(2)-induced AMPKalpha1 activation was blocked in the presence of the antioxidant N-acetyl-l-cysteine (NAC), and H(2)O(2) significantly increased the ratio of oxidized glutathione to glutathione (GSSG/GSH) concentrations, a sensitive marker of oxidative stress. H(2)O(2) did not cause an increase in the conventional parameters of AMPK activation, such as AMP and AMP/ATP. H(2)O(2) increased 3-O-methyl-d-glucose transport, and this increase was partially, but significantly, blocked in the presence of NAC. Results were similar when the muscles were incubated in a superoxide-generating system using hypoxanthine and xanthine oxidase. Taken together, our data suggest that acute oxidative stress activates AMPKalpha1 in skeletal muscle via an AMP-independent mechanism and leads to an increase in the rate of glucose transport, at least in part, via an AMPKalpha1-mediated mechanism.
AMP-Activated Protein Kinases↗
Relationship between the preference for sake (Japanese rice wine) and the movements of metabolic parameters coinciding with sake intake.
Selection of foods by animals largely depends on their physiological condition. In this paper, we reported how physiological changes in rats after ingestion of sake (Japanese rice wine) affected their preference for different kinds of sake. Rats could discriminate among various kinds of sakes in a two-bottle choice test, even after adjustment of the glucose concentration or alcohol concentration of the sake, suggesting that the choice of a sake by animals was based on more than one ingredient. To identify effect of a rat's physiological condition on the selection of sake, we monitored the levels of blood glucose, nonesterified fatty acids (NEFA), and ketone bodies in serum in mice after forced intragastric ingestion of sake that had previously been offered to the rats in a two-bottle choice test. Blood glucose levels in mice were not different between the rats fed the palatable and unpalatable sakes, and the NEFA level and ketone level were high in rats fed the unpalatable sake. To further clarify the relationship between physiological condition and preference for sake, rats were offered eight kinds of Junmai-syu, which is made with only rice and no sub-ingredient. Rats could still discriminate among Junmai-syu. Furthermore, with two exceptions, the preference for a sake was significantly correlated with the ketone level. The order in the ratio of blood insulin level to blood glucagon level, which is an indicator of metabolism, was correlated with the order in preference to sake. These results suggest that some physiological factors besides oral stimulation also are important factors in the selection of a sake.
Animal Feed↗
Effects of physical fatigue in mice on learning performance in a water maze.
We investigated the effects of physical fatigue produced by swimming exercise on learning the Morris water maze in BALB/c mice. We measured the escape latency in the maze immediately after the swimming exercise. The control group was soaked in the water but not fatigued. For easier tasks, like one with an obvious cue flag, the escape latency was not changed by exercise fatigue. However, escape latency was increased after exercise fatigue for more difficult tasks of spatial learning. These results appear to suggest that physical fatigue impaired learning performance. The effects of swimming exercise fatigue on learning efficiency were then investigated. Mice were continuously fatigued during the spatial learning period. This increased escape latency between the first and third sessions. The results suggest that learning efficiency was impaired by exercise fatigue. This system may be useful for screening new foods used to enhance brain function during exercise.
Animals↗
Upregulation of uncoupling proteins by oral administration of capsiate, a nonpungent capsaicin analog.
Capsiate is a nonpungent capsaicin analog, a recently identified principle of the nonpungent red pepper cultivar CH-19 Sweet. In the present study, we report that 2-wk treatment of capsiate increased metabolic rate and promoted fat oxidation at rest, suggesting that capsiate may prevent obesity. To explain these effects, at least in part, we examined uncoupling proteins (UCPs) and thyroid hormones. UCPs and thyroid hormones play important roles in energy expenditure, the maintenance of body weight, and thermoregulation. Two-week treatment of capsiate increased the levels of UCP1 protein and mRNA in brown adipose tissue and UCP2 mRNA in white adipose tissue. This dose of capsiate did not change serum triiodothyronine or thyroxine levels. A single dose of capsiate temporarily raised both UCP1 mRNA in brown adipose tissue and UCP3 mRNA in skeletal muscle. These results suggest that UCP1 and UCP2 may contribute to the promotion of energy metabolism by capsiate, but that thyroid hormones do not.
Adipose Tissue↗
Abietic acid activates peroxisome proliferator-activated receptor-gamma (PPARgamma) in RAW264.7 macrophages and 3T3-L1 adipocytes to regulate gene expression involved in inflammation and lipid metabolism.
Abietic acid is one of the terpenoids, which are multifunctional natural compounds. It has been reported that abietic acid suppresses effects on inflammation. However, the mechanism underlying the anti-inflammatory effects remains unclear. The present work indicates that abietic acid suppresses the protein expression of tumor necrosis factor-alpha and cyclooxygenase 2, which are involved in inflammation, in lipopolysaccharide-stimulated macrophages. Moreover, this effect resembles that of thiazolidinedione, a synthetic peroxisome proliferator-activated receptor-gamma (PPARgamma) ligand. Indeed, abietic acid activates PPARgamma in luciferase reporter assays. The activity of abietic acid induces PPARgamma target gene expression in RAW264.7 macrophages and 3T3-L1 adipocytes. These data indicate that abietic acid is a PPARgamma ligand and that its anti-inflammatory effect is partly due to the activation of PPARgamma in stimulated macrophages. The present work suggests a novel possibility that abietic acid, a naturally occurring compound, can be used not only for anti-inflammation but also for regulating lipid metabolism and atherosclerosis.
3T3 Cells↗
Purification and identification of a binding protein for pancreatic secretory trypsin inhibitor: a novel role of the inhibitor as an anti-granzyme A.
Pancreatic secretory trypsin inhibitor (PSTI) is a potent trypsin inhibitor that is mainly found in pancreatic juice. PSTI has been shown to bind specifically to a protein, distinct from trypsin, on the surface of dispersed cells obtained from tissues such as small intestine. In the present study, we affinity-purified the binding protein from the 2% (w/v) Triton X-100-soluble fraction of dispersed rat small-intestinal cells using recombinant rat PSTI. Partial N-terminal sequencing of the purified protein gave a sequence that was identical with the sequence of mouse granzyme A (GzmA), a tryptase produced in cytotoxic lymphocytes. We confirmed the formation of an affinity-cross-linked complex between (125)I-labelled PSTI and recombinant rat GzmA (rGzmA). In situ hybridization and immunostaining revealed the existence of GzmA-expressing intraepithelial lymphocytes in the rat small intestine. We concluded that the PSTI-binding protein isolated from the dispersed cells is GzmA that is produced in the lymphocytes of the tissue. The rGzmA hydrolysed the N -alpha-benzyloxycarbonyl-L-lysine thiobenzyl ester (BLT), and the BLT hydrolysis was inhibited by PSTI. Sulphated glycosaminoglycans, such as fucoidan or heparin, showed almost no effect on the inhibition of rGzmA by PSTI, whereas they decreased the inhibition by antithrombin III. In the present paper, we propose a novel role of PSTI as a GzmA inhibitor.
Animals↗
Importance of lipolysis in oral cavity for orosensory detection of fat.
Lingual lipase is usually secreted from von Ebner's glands, although there is great variation between species. Lingual lipase is thought to be an auxiliary enzyme for fat digestion and absorption in mammals; however, the reason for lipolysis in the oral cavity is not known. We focused on the gustatory sense and investigated the significance of lingual lipase in the perception of a fat taste by using orlistat, a potent lipase inhibitor. Five-minute two-bottle preference tests demonstrated that the addition of orlistat diminished the preference for triacylglycerides but not for free fatty acids. Radioactive triolein applied on rats' circumvallate papilla revealed that lingual lipase was released continuously to generate significant amounts of fatty acids and other lipolytic products within 1-5 s, which was enough time to taste fat. These findings suggest that lingual lipase is released to perceive the taste of triacylglycerides and to find nutritive lipids in food.
Animals↗
Role of gustation in the recognition of oleate and triolein in anosmic rats.
Recent studies suggest a chemical perception of dietary fat in the oral cavity. To examine the role of gustation for the recognition of oleate and triolein, very short-term (5-min), two-bottle preference tests were conducted in anosmic rats. To minimize the effects of olfaction, texture and postingestive effects, rats were rendered anosmic with intranasal zinc sulfate, test substances were suspended in 0.3% xanthan gum solution and test fluids were offered for 5 min. Rats preferred oleate fluid but not triolein fluid to the control of 0.3% xanthan gum solution. The preference threshold for oleate in the rat oral cavity was between 0.2% and 0.5%. In the two-bottle preference tests between oleate and triolein, rats preferred oleate fluid to triolein fluid, showing discrimination of oleate and triolein. The results suggest that rat recognizes oleate by a gustatory cue and that fatty acid but not triglyceride is important for gustatory recognition of fat.
Animals↗
Effects of oral stimulation with fats on the cephalic phase of pancreatic enzyme secretion in esophagostomized rats.
Recent studies suggest that there is a chemical perception of dietary fat in the oral cavity. A much greater response in the cephalic phase of pancreatic secretion is obtained by palatable taste stimuli. To examine the perception of dietary fat in the oral cavity, we determined whether or not oral stimulation with fat alters the cephalic phase of pancreatic enzyme secretion. A cannula was inserted into the common bile duct of rats to collect bile-pancreatic juice, and the animals were esophagostomized to prevent stimulation of the gastrointestinal tract with the test substances. The cephalic phase of pancreatic enzyme secretion was enhanced by oral stimulation with the long chain fatty acids, oleic acid, linoleic acid and linolenic acid, but was unaffected by the middle chain fatty acid, caprylic acid, and long chain fatty acid derivatives, methyl oleate and methyl linoleate. This selectivity is consistent with our previous findings that, in a short term two-bottle preference test, rats prefer long chain fatty acids to triglycerides, middle chain fatty acids or long chain fatty acid derivatives. These results suggest that long chain fatty acids trigger chemical reception in the oral cavity, and the length of the fatty acid chain and the presence or absence of carboxylate groups are related to recognition of fat.
Animals↗
Integration of orosensory and postingestive stimuli for the control of excessive fat intake in mice.
OBJECTIVES: Long-term preferences for, and reinforcement effects of, undigested fat substitutes were investigated by means of a two-bottle choice test and the conditioned place preference (CPP) test. METHODS: We tested intact corn oil and sorbitol fatty acid esters, which have been developed as non-digestible fat substitutes with low energy (1.5 kcal/g). RESULTS: Palatability of the sorbitol fatty acid esters was similar to corn oil over 30 min in the short-term two-bottle choice test in mice. However, mice did not continue to eat the fat substitute in the long-term two-bottle choice test, which included postprandial feedback effects. Moreover, sorbitol fatty acid ester did not act as a reinforcer in the CPP test. Mice with 0.1 mL of corn oil placed into their stomachs just before conditioning showed reinforcing effects on taking sorbitol fatty acid ester in the CPP test. However, intragastric administration of corn oil alone without stimulation of the oral cavity did not show any such reinforcing effects against corn oil. CONCLUSIONS: These results suggest that the postingestible effects of corn oil are involved in long-term preference and reinforcing effects.
Animals↗
A soybean peptide isolate diet promotes postprandial carbohydrate oxidation and energy expenditure in type II diabetic mice.
The aim of the present study was to determine the effects of dietary proteins on the oxidation of dietary carbohydrate and lipids in type II diabetic mice. KK-A(y) strain mice were provided free access to a high fat diet (30% of energy as fat) for an initial 4-wk period to induce diabetes. To reduce body weight gain, the mice were subsequently fed restrictive isoenergetic and isonitrogenous diets (35% of energy as protein and 5% as fat) based on either casein or soy protein isolate hydrolysate (SPI-H) for 4 wk. To measure exogenous carbohydrate and lipid oxidation, the mice were fed a diet containing (13)C-glucose or (13)C-triolein while they were in a respiratory chamber for 72 h. Postprandial energy expenditure was higher in the SPI-H than in the casein group; this difference was due to an increase in postprandial exogenous and endogenous carbohydrate oxidation. There were no differences in 24-h energy expenditure between dietary groups. Oxidation of exogenous carbohydrate tended to be higher (P = 0.054) in the SPI-H group during the 24 h of measurement. Fecal excretion of (13)C-glucose was lower but the excretion of lipid was higher in mice fed the SPI-H diet than in casein-fed mice. These results indicate that in type II diabetic mice, dietary SPI-H not only inhibits the absorption of dietary lipids and increases the absorption of dietary carbohydrates but also augments postprandial energy expenditure, which is accompanied by a postprandial increase in oxidation of dietary carbohydrates.
Animals↗
Autonomic nervous responses according to preference for the odor of jasmine tea.
The effect of jasmine tea odor on the autonomic nervous system was investigated by a power spectral analysis of the heart rate variability. We assigned eight volunteers to two groups with either a predilection for or antipathy toward the jasmine tea odor. We tested both high- and low-intensity jasmine tea odors. The low-intensity odor was produced by diluting 20-fold the jasmine tea used for the high-intensity odor test. The low-intensity odor produced an increase in parasympathetic nervous activity in both the predilection and antipathy groups. The high-intensity odor produced an increase in parasympathetic nervous activity in the predilection group, but an increase in sympathetic nervous activity in the antipathy group. The odor of Chinese green tea, a basic ingredient of jasmine tea, produced no effects similar to those of the jasmine tea odor. These results suggest that the jasmine tea odor activated the parasympathetic nerve, whereas the higher-intensity odor activated the sympathetic nerve in those subjects who disliked the odor.
Administration, Inhalation↗
Regulation of the peripheral body temperature by foods: a temperature decrease induced by the Japanese persimmon (kaki, Diospyros kaki).
We investigated whether the ingestion of the Japanese persimmon (kaki, Diospyros kaki) could lower the human peripheral body temperature. It was found that the temperatures recorded at the foot and wrist were depressed after kaki consumption compared to after the same amount of water consumption. The effects of ingesting freeze-dried kaki and eating a cookie (as its nutritional counterpart) containing the same amount of carbohydrate, protein, fat, and water were compared. A similar temperature-reducing effect of kaki was observed. The recovery of finger temperature after soaking the finger in ice-cooled water was also studied. The temperature recovery was delayed after kaki consumption. It was thus quantitatively demonstrated that ingesting kaki indeed had the effect of lowering (or repressing the rise) of the peripheral human body temperature, as has been traditionally believed in China for many hundreds of years.
Adult↗