Researchers Database

kurashina tomoyuki

    BasicSciencerelatedtoNursing Associate Professor
Last Updated :2021/11/23

Researcher Information

J-Global ID

Published Papers

  • Kurashina T, Nagasaka S, Watanabe N, Yabe D, Sugi N, Nin K, Hosokawa M, Nomura Y, Fukushima M, Nakai Y, Nishimura F, Taniguchi A
    Journal of atherosclerosis and thrombosis 1340-3478 2014/04 [Refereed][Not invited]
  • Boldbaatar Damdindorj, Katsuya Dezaki, Tomoyuki Kurashina, Hideyuki Sone, Rauza Rita, Masafumi Kakei, Toshihiko Yada
    FEBS LETTERS 16 586 (16) 2555 - 2562 0014-5793 2012/07 [Refereed][Not invited]
     
    We studied interactive effects of insulinotropic GLP-1 and insulinostatic ghrelin on rat pancreatic islets. GLP-1 potentiated glucose-induced insulin release and cAMP production in isolated islets and [Ca2+](i) increases in single beta-cells, and these potentiations were attenuated by ghrelin. Ghrelin suppressed [Ca2+](i) responses to an adenylate cyclase activator forskolin. Moreover, GLP-1-induced insulin release and cAMP production were markedly enhanced by [D-lys(3)]-GHRP-6, a ghrelin receptor antagonist, in isolated islets. These results indicate that both exogenous and endogenous islet-derived ghrelin counteracts glucose-dependent GLP-1 action to increase cAMP production, [Ca2+](i) and insulin release in islet beta-cells, positioning ghrelin as a modulator of insulinotropic GLP-1. (c) 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
  • Katsuya Dezaki, Boldbaatar Damdindorj, Hideyuki Sone, Oleg Dyachok, Anders Tengholm, Erik Gylfe, Tomoyuki Kurashina, Masashi Yoshida, Masafumi Kakei, Toshihiko Yada
    DIABETES 9 60 (9) 2315 - 2324 0012-1797 2011/09 [Refereed][Not invited]
     
    OBJECTIVE-Ghrelin reportedly restricts insulin release in islet beta-cells via the G alpha(i2) subtype of G-proteins and thereby regulates glucose homeostasis. This study explored whether ghrelin regulates cAMP signaling and whether this regulation induces insulinostatic cascade in islet beta-cells. RESEARCH DESIGN AND METHODS-Insulin release was measured in rat perfused pancreas and isolated islets and cAMP production in isolated islets. Cytosolic cAMP concentrations ([cAMP](i)) were monitored in mouse MIN6 cells using evanescent-wave fluorescence imaging. In rat single beta-cells, cytosolic protein kinase-A activity ([PKA](i)) and Ca2+ concentration ([Ca2+](i)) were measured by DR-II and fura-2 microfluorometry, respectively, and whole cell currents by patch-clamp technique. RESULTS-Ghrelin suppressed glucose (8.3 mmol/L)-induced insulin release in rat perfused pancreas and isolated islets, and these effects of ghrelin were blunted in the presence of cAMP analogs or adenylate cyclase inhibitor. Glucose-induced cAMP production in isolated islets was attenuated by ghrelin and enhanced by ghrelin receptor antagonist and anti-ghrelin antiserum, which counteract endogenous islet-derived ghrelin. Ghrelin inhibited the glucose-induced [cAMP](i) elevation and [PKA](i) activation in MIN6 and rat beta-cells, respectively. Furthermore, ghrelin potentiated voltage-dependent K+ (Kv) channel currents without altering Ca2+ channel currents and attenuated glucose-induced [Ca2+](i) increases in rat beta-cells in a PKA-dependent manner. CONCLUSIONS-Ghrelin directly interacts with islet beta-cells to attenuate glucose-induced cAMP production and PKA activation, which lead In activation of Kv channels and suppression of glucose-induced [Ca2+](i) increase and insulin release. Diabetes 60:2315-2324, 2011
  • Shuichi Nagashima, Hiroaki Yagyu, Nirei Takahashi, Tomoyuki Kurashina, Manabu Takahashi, Takeshi Tsuchita, Fumiko Tazoe, Xiao Li Wang, Tumenbayar Bayasgalan, Naoko Sato, Kenta Okada, Shoichiro Nagasaka, Takaya Gotoh, Masayuki Kojima, Masanobu Hyodo, Hisanaga Horie, Yoshinori Hosoya, Masaki Okada, Yoshikazu Yasuda, Hiroyuki Fujiwara, Michitaka Ohwada, Sadahiko Iwamoto, Mitsuaki Suzuki, Hideo Nagai, Shun Ishibashi
    JOURNAL OF ATHEROSCLEROSIS AND THROMBOSIS 18 (3) 190 - 199 1340-3478 2011 [Refereed][Not invited]
     
    Aim: Adipocyte lipolysis is mediated by a family of triglyceride (TG) lipases consisting of hormone-sensitive lipase (LIPE), adipose triglyceride lipase (PNPLA2) and carboxylesterase 1 (CES1); however, little is known about the relationship between the expression of each gene in different depots and TG lipase activity or obesity Method: We measured both mRNA expression levels of the lipolytic enzymes (LIPE, PNPLA2 and CES1) and TG lipase activities of biopsy samples obtained from subcutaneous, omental and mesenteric adipose tissues of 34 patients who underwent abdominal surgery. The results were correlated with clinical parameters: adiposity measures, parameters for insulin resistance and plasma lipid levels. Results: PNPLA2 mRNA levels were slightly higher in omental fat than subcutaneous fat. Cytosolic TG lipase activities were positively correlated with the mRNA levels of CES1 in subcutaneous fat and mesenteric fat, while they were correlated with those of PNPLA2 in omental fat. The mRNA levels of LIPE were negatively correlated with various measures of adiposity in subcutaneous fat. The mRNA levels of CES1 were positively correlated with various measures of adiposity, particularly those estimated by CT in the three depots; they were also positively correlated with plasma LDL-cholesterol levels in omental fat. In contrast, the mRNA levels of PNPLA2 were not significantly associated with adiposity. Conclusions: The positive correlations of the expression of CES1 with cytosolic TG lipase activities as well as with adiposity suggest that CES1 is involved in lipolysis, thereby contributing to the development of obesity-associated phenotypes. On the other hand, the expression of LIPE is negatively correlated with adiposity. These distinct regulatory patterns of lipolytic genes may underlie the complex phenotypes associated with human obesity.
  • Natsu Yoshida, Yuko Maejima, Udval Sedbazar, Akihiko Ando, Hideharu Kurita, Boldbaatar Damdindorj, Eisuke Takano, Darambazar Gantulga, Yusaku Iwasaki, Tomoyuki Kurashina, Tatsushi Onaka, Katsuya Dezaki, Masanori Nakata, Masatomo Mori, Toshihiko Yada
    AGING-US 2 (11) 775 - 784 1945-4589 2010/11 [Refereed][Not invited]
     
    A recently discovered satiety molecule, nesfatin-1, is localized in neurons of the hypothalamus and brain stem and colocalized with stress-related substances, corticotropin-releasing hormone (CRH), oxytocin, proopiomelanocortin, noradrenaline (NA) and 5-hydroxytryptamine (5-HT). Intracerebroventricular (icv) administration of nesfatin-1 produces fear-related behaviors and potentiates stressor-induced increases in plasma adrenocorticotropic hormone (ACTH) and corticosterone levels in rats. These findings suggest a link between nesfatin-1 and stress. In the present study, we aimed to further clarify the neuronal network by which nesfatin-1 could induce stress responses in rats. Restraint stress induced c-Fos expressions in nesfatin-1-immunoreactive neurons in the paraventricular nucleus (PVN) and supraoptic nucleus (SON) of the hypothalamus, and in the nucleus of solitary tract (NTS), locus coeruleus (LC) and dorsal raphe nucleus (DR) in the brain stem, without altering plasma nesfatin-1 levels. Icv nesfatin-1 induced c-Fos expressions in the PVN, SON, NTS, LC, DR and median raphe nucleus, including PVN-CRH, NTS-NA, LC-NA and DR-5-HT neurons. Nesfatin-1 increased cytosolic Ca(2+) concentration in the CRH-immunoreactive neurons isolated from PVN. Icv nesfatin-1 increased plasma ACTH and corticosterone levels. These results indicate that the central nesfatin-1 system is stimulated by stress and activates CRH, NA and 5-HT neurons and hypothalamic-pituitary-adrenal axis, evoking both central and peripheral stress responses.

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