Publications by authors named "Hiroko Negishi"

Sex steroids modify feeding behavior and body weight regulation, and androgen reportedly augments food intake and body weight gain. To elucidate the role of endogenous androgens in the feeding regulation induced by reduced glucose availability, we examined the effect of gonadectomy (orchiectomy) on food intake and orexin A neuron's activity in the lateral hypothalamic/perifornical area (LH/PFA) in response to reduced glucose availability (glucoprivation) induced by 2-deoxy-d-glucose (2DG) administration in male rats. Rats (7W) were bilaterally orchiectomized (ORX group) or sham operated (Sham group).

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Our previous study demonstrated that chronic estrogen replacement in ovariectomized rats reduces food intake and augments c-Fos expression in the suprachiasmatic nucleus (SCN), specifically during the light phase. Here, we hypothesized that serotonergic neurons in the central nervous system (CNS), which have anorectic action and play a role in regulating circadian rhythm, mediate the light phase-specific anorectic action of estrogen, and that selective serotonin reuptake inhibitors (SSRIs) mimic the hypophagic action of estrogen. Female Wistar rats were ovariectomized and treated with estradiol (E2) or cholesterol by subcutaneously implanting a silicon capsule containing E2 or cholesterol.

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Silibinin, a flavonolignan derived from milk thistle (Silybum marianum), has been revealed to have a beneficial effect on improving diabetes-impaired glycemic control. However, the underlying mechanism is still unclear. In the present study, to evaluate whether the gut-brain-liver axis, an important neural pathway for the control of hepatic glucose production, is involved in silibinin-regulated glucose homeostasis, the expression of glucagon-like peptide-1 receptor (GLP1R) in the duodenum, activation of neurons in the nucleus of the solitary tract (NTS), as well as glycogen accumulation and expression of gluconeogenic enzymes in the livers of diabetic SHRSP·Z-Leprfa/IzmDmcr (SP·ZF) rats with 4-week oral administration of silibinin (100 and 300 mg kg-1 day-1) were evaluated.

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Objective: To evaluate whether endothelial dysfunction and hypertension are prevented by trans-cinnamaldehyde (tCA) through the activation of endothelial nitric oxide synthase (eNOS).

Methods: Human umbilical vein endothelial cells (HUVECs) were cultured in vitro and stimulated with tCA to determine cell viability using the methyl thiazolyl tetrazolium assay. The effect of tCA on nitric oxide (NO) production was determined by diaminofluorescein-dyes in the absence or presence of inhibitors of eNOS, AMPK, PKA, and AKT.

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Chronic estrogen replacement in ovariectomized rats attenuates food intake and enhances c-Fos expression in the suprachiasmatic nucleus (SCN), specifically during the light phase. -equol, a metabolite of daidzein, has a strong affinity for estrogen receptor (ER)-β and exerts estrogenic activity. The purpose of the present study was to elucidate whether -equol exerts an estrogen-like anorectic effect by modifying the regulation of the circadian feeding rhythm in ovariectomized rats.

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Stroke-prone spontaneously hypertensive rats (SHRSP/Izm; SHRSP) develop severe hypertension and die of cerebral stroke. However, the genetic mechanisms underlying their stroke susceptibility have not been clarified yet. In this study, we used astrocytes from the newborn brain cortex of spontaneously hypertensive rats (SHR/Izm; SHR) and SHRSP to find the difference of genetic characteristics.

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Angelica acutiloba Kitagawa (Yamato Toki) is a herbal medicine known to exhibit various health effects. In this study, we used a rat model to examine the effects of two different Yamato Toki extracts on the blood flow response of the instep of the hind paw. Twelve-week- old male stroke-prone spontaneously hypertensive rats (SHRSP) were orally given 200 mg of a water extract of Yamato Toki (n=6), 200 mg of an ethanol extract of Yamato Toki (n = 6), 30 mg/kg of nicardipine (n = 6) as a positive control and saline (n = 6) as a negative control.

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We aimed to investigate the effect of berberine on adipose tissues, as well as its effect on renal injury in 3T3-L1 cells and spontaneously hypertensive rats. 3T3-L1 cells were cultured and treated with berberine (5-20 pM) from days 3 to 8. Berberine added to the cultured medium could significantly down-regulate transcription factors, including CCAAT/enhancer binding protein β, CCAAT/enhancer binding protein a, and peroxisome pro liferator-activated receptor y, and suppress peroxisome proliferator-activated receptor target genes, such as adipocyte fatty acid binding protein and fatty acid synthase, and inhibit 3T3-Ll fibroblast differentiation to adipocytes.

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In order to elucidate the involvement of melanin-concentrating hormone (MCH) and orexin-A (ORX-A) neurons of the perifornical/lateral hypothalamic areas (PF/LH) in the regulation of food intake induced by acutely reduced glucose availability, we examined the food intake response and c-Fos expression in the MCH and ORX-A neurons in the PF/LH during 2-deoxy-D-glucose (2DG)-induced glucoprivation (400 mg/kg; i.v.) and systemic insulin-induced hypoglycemia (5 U/kg; s.

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The generation of oxidative stress, characterized by enhanced reactive oxygen species (ROS) formation, has been found in obesity. ROS production was increased during the differentiation of 3T3-L1 cells into adipocytes. We previously reported that caffeic acid phenethyl ester (CAPE) suppresses 3T3-L1 differentiation to adipocytes through the inhibition of peroxisome proliferator-activated receptor γ.

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Obesity is a condition in which excess body fat accumulates due to lipids producing adipocytes and an increased number of differentiated mature cells. Recently, new findings have shown that macrophages infiltrate into adipose tissues and produce various pro-inflammatory cytokines in obese subjects. The inflammatory changes induced by the cross-talk between adipocytes and macrophages are critical for the pathophysiology of obesity and thus of metabolic syndrome.

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We previously reported that caffeic acid phenethyl ester (CAPE) suppresses 3T3-L1 differentiation to adipocytes through the inhibition of peroxisome proliferator-activated receptor (PPAR) gamma, CCAAT/enhancer-binding protein (C/EBP) alpha, fatty acid synthase (Fas) and adipocytes-specific fatty acid binding protein 2 (aP2) expressions (Juman et al., Biol. Pharm.

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A new chromone derivative named terminalianone (1) was isolated from the African plant, Terminalia brownii Fresen (Combretaceae) in Tanzania. Its structure was determined to be 7-hydroxy-3-[6'-hydroxyphenyl-2'-oxo-ethyl]chromone by FAB-MS and NMR spectral data.

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We investigated the inhibitory effect of caffeic acid phenethyl ester (CAPE) on the differentiation of 3T3-L1 mouse fibroblasts to adipocytes. 3T3-L1 cells were differentiated for adipocytes given high glucose Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% fetal bovine serum (FBS), 1 microM dexamethasone (DEX), 500 microM isobutylmethylxanthine (IBMX), and 5 microg/ml insulin for 7 days. After differentiation, cells were stained with Oil-Red-O to detect oil droplets in adipocytes.

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1. Recent studies have identified potential beneficial effects of eating nuts, most of which have substantial amounts of monounsaturated fatty acids (MUFA). Macadamia nuts consist of 75% fat by weight, 80% of which is MUFA (palmitoleic acid).

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Oxidative stress was reported to be involved not only in cardiovascular diseases, but also in hypertension. Epidemiologic studies indicated that tea consumption slightly reduces blood pressure. We conducted two studies to determine whether black and green tea can lower blood pressure (BP) in stroke-prone spontaneously hypertensive rats (SHRSP).

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Cerebral ischemia and recirculation cause delayed neuronal death in rodents, such as Mongolian gerbils and stroke-prone spontaneously hypertensive rats (SHRSP), which were used as an experimental stroke model. It was documented that an enhanced nitric oxide production, the occurrence of apoptosis, and an attenuated redox regulatory system contribute to the development of delayed neuronal death. Many studies have suggested the beneficial antioxidant effects of antioxidant nutrients such as vitamin E, green tea extract, ginkgo biloba extract, resveratrol and niacin in cerebral ischemia and recirculation brain injury.

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1. We showed that a nutritional factor was able to attenuate the development of hypertension and its related diseases in stroke-prone spontaneously hypertensive rats (SHRSP). In the present study, the effect of Wakame, an edible brown seaweed, on the development of stroke was examined in SHRSP.

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As part of the Japan-China Cooperative Research Project of the WHO-Cardiovascular Disease and Alimentary Comparison Study, a cross-sectional study was carried out to investigate risk factors for high blood pressure (BP) in male adults in Chongqing, China. Subjects with hypertension (HT) were defined as those if they had systolic BP (SBP) > or = 140 mmHg or diastolic BP (DBP) > or = 90 mmHg or if they were receiving anti-hypertensive drug therapy. Subjects were also categorized into three groups according to their level of education, i.

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