Publications (7)9.77 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Bright light therapy is used as the primary treatment for seasonal affective disorder; however, the mechanisms underlying its antidepressant effect are not fully understood. Previously, we found that C57BL/6J mice exhibit increased depression-like behavior during a short-day condition (SD) and have lowered brain serotonin (5-HT) content. This study analyzed the effect of bright light on depression-like behaviors and the brain serotonergic system using the C57BL/6J mice. In the mice maintained under SD, bright light treatment (1000 lux, daily 1h exposure) for 1 week reduced immobility time in the forced swimming test and increased intake of saccharin solution in a saccharin intake test. However, the light treatment did not modify 5-HT content and selective 5-HT uptake in the amygdala, or temporal patterns of core body temperature and wheel-running activity throughout a day. In the next experiment, we attempted to enhance the effect of bright light by using l-serine, a precursor of d-serine that acts as an N-methyl-d-aspartic acid receptor coagonist. Daily subcutaneous injection of l-serine for 2 weeks prior to the bright light strongly reduced the immobility time in the forced swimming test, suggesting a synergistic effect of light and l-serine. Furthermore, bright light increased the total number of 5-HT-immunoreactive cells and cells that had colocalized 5-HT and c-Fos immunosignals in several subregions of the raphe nuclei. These effects were potentiated by prior injection of l-serine. These data suggest that the bright light may elicit an antidepressant-like effect via enhanced 5-HT signals in the brain and l-serinecan enhance these effects. Copyright © 2015. Published by Elsevier Inc.
    No preview · Article · Sep 2015 · Brain research bulletin
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The senescence accelerated mouse prone 8 substrain (SAM-P8), widely accepted as an animal model for studying aging and antiaging drugs, was used to examine the effects of dietary supplementation with extracts of Cistanche deserticola (ECD) which has been used extensively in traditional Chinese medicine because of its perceived ability to promote immune function in the elderly. Eight-month-old male SAM-P8 mice were treated with ECD by daily oral administrations for 4 weeks. The results showed that dietary supplementation of 150 mg/kg and 450 mg/kg of ECD could extend the life span measured by Kaplan-Meier survival analysis in dose-dependent manner. Dietary supplementation of SAM-P8 mice for 4 weeks with 100, 500, and 2500 mg/kg of ECD was shown to result in significant increases in both naive T and natural killer cells in blood and spleen cell populations. In contrast, peripheral memory T cells and proinflammatory cytokine, IL-6 in serum, were substantially decreased in the mice that ingested 100 and 500 mg/kg of ECD daily. Additionally, Sca-1 positive cells, the recognized progenitors of peripheral naive T cells, were restored in parallel. Our results provide clear experimental support for long standing clinical observational studies showing that Cistanche deserticola possesses significant effects in extending life span and suggest this is achieved by antagonizing immunosenescence.
    Full-text · Article · Jan 2014 · Evidence-based Complementary and Alternative Medicine
  • [Show abstract] [Hide abstract]
    ABSTRACT: Kale (Brassica oleracea L. var acephala DC) is a leafy green vegetable belonging to the cabbage family (Brassicaceae) that contains a large amount of health-promoting phytochemicals. There are any reports about the effects of kale ingestion on the chemoprevention function and mechanism, but the interactions between kale and drugs have not been researched. We investigated the effects of kale intake on cytochrome P450 (CYP) metabolism by using cocktail probe drugs, including midazolam (for CYP3A4), caffeine (for CYP1A2), dextromethorphan (for CYP2D6), tolbutamide (for CYP2C9), omeprazole (for CYP2C19), and chlorzoxazone (for CYP2E1). Cocktail drugs were administered into rats treated with kale and cabbage (2000 mg/kg) for a week. The results showed that kale intake induced a significant increase in plasma levels and the AUC of midazolam, caffeine, and dextromethorphan. In addition, the plasma concentration and AUC of omeprazole tended to increase. Additionally, no almost differences in the mRNA expression levels of CYP enzymes in the liver were observed. In conclusion, kale ingestion was considered to have an inhibitory effect on the activities of CYP3A4, 1A2, 2D6, and 2C19 for a reason competitive inhibition than inhibitory changes in the mRNA expressions.
    No preview · Article · Sep 2012 · Biomedical Research
  • [Show abstract] [Hide abstract]
    ABSTRACT: Ingested L-serine reduces the locomotor activity of socially isolated rats, but its effects on brain function and its underlying mechanisms of action have not yet been fully clarified. D-Serine is synthesized from L-serine by serine racemase and intraperitoneal injection of this D-amino acid attenuates depressive-like behavior in rats. We therefore hypothesized that oral intake of L-serine would stimulate the metabolism of L-serine to D-serine, and subsequently not only L-serine but also the newly formed D-serine would simultaneously affect brain functions and/or behaviors. In the present study, as the first step to test this hypothesis, L- and D-serine levels of the plasma and brain (cerebral cortex and hippocampus) were investigated at 0.5, 2, 6 and 10 h after oral administration of L-serine (6 mmol/kg) to fasted rats. In the plasma, the levels of both L-serine and D-serine were significantly increased at 0.5 h compared to control rats and thereafter their levels gradually decreased over time and had returned to the control values by 10 h. In both the cerebral cortex and the hippocampus, the increase in the level of L-serine paralleled the increase in the plasma L-serine level, whereas the levels of D-serine increased slowly for over 10 h, resulting in a small increase in D-serine. The combined data indicate that oral intake of L-serine might influence brain functions and/or behaviors not only through activity of L-serine itself but also due to activity of its metabolite D-serine.
    No preview · Article · Sep 2012 · Letters in Drug Design & Discovery
  • [Show abstract] [Hide abstract]
    ABSTRACT: Kale is a cruciferous vegetable (Brassicaceae) that contains a large amount of health-promoting phytochemicals. The chronic ingestion of cabbage of the same family is known to accelerate conjugating acetaminophen (AA) and decrease the plasma AA level. Therefore, we examined to clarify the effects of kale on the pharmacokinetics of AA, its glucuronide (AA-G) and sulfate (AA-S). AA was orally administered to rats pre-treated with kale or cabbage (2000 mg/kg/day) for one week. Blood samples were collected from the jugular vein, and the concentrations of AA, AA-G and AA-S were determined. In results, kale ingestion induced an increase in the area under the concentration-time curve (AUC) and a decrease in the clearance of AA, whereas cabbage had almost no influence. In addition, there were significant differences in the AUC of AA-G between the control and kale groups. mRNA expression levels of UDP-glucuronosyltransferases, the enzymes involved in glucuronidation, in the kale group were significantly higher than those in the control group. In conclusion, kale ingestion increased the plasma concentrations of both AA and AA-G. The results suggest that kale ingestion accelerates the glucuronidation of AA, but an increase of plasma AA levels has a different cause than the cause of glucuronidation.
    No preview · Article · Dec 2011 · Biomedical Research
  • [Show abstract] [Hide abstract]
    ABSTRACT: The EtOH extract of tarragon Artemisia dracunculus, a perennial herb in the family Asteraceae, was found to potently inhibit α-melanocyte-stimulating hormone (α-MSH) induced melanin production in B16 mouse melanoma cells. Bioassay-guided fractionation led to the isolation of two alkamide compounds, isobutyl (1) and piperidiyl (2) amides of undeca-2E,4E-dien-8,10-dynoic acid. The respective EC(50) values for melanin biosynthesis inhibition were 1.8 and 2.3 µg/mL for 1 and 2.
    No preview · Article · Aug 2011 · Bioscience Biotechnology and Biochemistry
  • [Show abstract] [Hide abstract]
    ABSTRACT: An EtOH extract of fruits of Piper longum was found to exhibit a potent inhibitory effect against alpha-melanocyte-stimulating hormone (alpha-MSH)-induced melanin production in B16 mouse melanoma cells. Bioassay-directed fractionation led to the isolation of prenylated phenolic compounds bakuchiol, bavachin, and isobavachalcone. These compounds and the crude extract of the fruits of P. longum may have suppressive effects against pigmentation by melanin in the skin.
    No preview · Article · Jul 2010 · Bioscience Biotechnology and Biochemistry