Directory of Researchers

MORITA Mitsuhiro
Graduate School of Science / Division of Biology
Associate Professor
Biology
Last Updated :2021/11/20

Researcher Profile and Settings

Affiliation

  • <Faculty / Graduate School / Others>

    Graduate School of Science / Division of Biology
  • <Related Faculty / Graduate School / Others>

    Faculty of Science / Department of Biology, Organization for Advanced and Integrated Research

Teaching

Research Activities

Research Interests

  • 包括脳ネットワーク
  • アストロサイト
  • カルシウム
  • 脳損傷

Research Areas

  • Life sciences / Clinical pharmacy
  • Life sciences / Physiology
  • Life sciences / Clinical pharmacy
  • Life sciences / Physiology
  • Life sciences / Neuroscience - general
  • Life sciences / Neuroscience - general

Committee Memberships

  • Neural Regeneration Research, Editorial Board Member

Published Papers

  • Maja Potokar, Mitsuhiro Morita, Gerhard Wiche, Jernej Jorgačevski

    Despite the remarkable complexity of the individual neuron and of neuronal circuits, it has been clear for quite a while that, in order to understand the functioning of the brain, the contribution of other cell types in the brain have to be accounted for. Among glial cells, astrocytes have multiple roles in orchestrating neuronal functions. Their communication with neurons by exchanging signaling molecules and removing molecules from extracellular space takes place at several levels and is governed by different cellular processes, supported by multiple cellular structures, including the cytoskeleton. Intermediate filaments in astrocytes are emerging as important integrators of cellular processes. Astrocytes express five types of intermediate filaments: glial fibrillary acidic protein (GFAP); vimentin; nestin; synemin; lamins. Variability, interactions with different cellular structures and the particular roles of individual intermediate filaments in astrocytes have been studied extensively in the case of GFAP and vimentin, but far less attention has been given to nestin, synemin and lamins. Similarly, the interplay between different types of cytoskeleton and the interaction between the cytoskeleton and membranous structures, which is mediated by cytolinker proteins, are understudied in astrocytes. The present review summarizes the basic properties of astrocytic intermediate filaments and of other cytoskeletal macromolecules, such as cytolinker proteins, and describes the current knowledge of their roles in normal physiological and pathological conditions.

    02 Jul. 2020, Cells, 9 (7), English, International magazine

    Scientific journal

  • Eriko Furube, Haruna Ishii, Yuri Nambu, Erkin Kurganov, Sumiharu Nagaoka, Mitsuhiro Morita, Seiji Miyata

    Tanycyte is a subtype of ependymal cells which extend long radial processes to brain parenchyma. The present study showed that tanycyte-like ependymal cells in the organum vasculosum of the lamina terminalis, subfornical organ and central canal (CC) expressed neural stem cell (NSC) marker nestin, glial fibrillar acidic protein and sex determining region Y. Proliferation of these tanycyte-like ependymal cells was promoted by continuous intracerebroventricular infusion of fibroblast growth factor-2 and epidermal growth factor. Tanycytes-like ependymal cells in the CC are able to form self-renewing neurospheres and give rise mostly to new astrocytes and oligodendrocytes. Collagenase-induced small medullary hemorrhage increased proliferation of tanycyte-like ependymal cells in the CC. These results demonstrate that these tanycyte-like ependymal cells of the adult mouse brain are NSCs and suggest that they serve as a source for providing new neuronal lineage cells upon brain damage in the medulla oblongata.

    18 Feb. 2020, Scientific reports, 10 (1), 2826 - 2826, English, International magazine

    [Refereed]

  • Sudheesh K. Rajput, Manoj Kumar, Xiangyu Quan, Mitsuhiro Morita, Tomoyuki Furuyashiki, Yasuhiro Awatsuji, Enrique Tajahuerce, Osamu Matoba

    SPIE-Intl Soc Optical Eng, 12 Nov. 2019, Journal of Biomedical Optics, 25 (03), 1 - 1

    [Refereed]

    Scientific journal

  • Daishi Hiratsuka, Erkin Kurganov, Eriko Furube, Mitsuhiro Morita, Seiji Miyata

    The myelin sheath is critical in maintaining normal functions of the adult central nervous system (CNS) and the loss of the myelin sheath results in various neurological diseases. Although remyelination is the intrinsic repair system against demyelination that new myelin sheath is formed around axons in the adult CNS, little has been reported on remyelination system in the medulla oblongata. In the present study, we showed that the proliferation of oligodendrocyte progenitor cells (OPCs) was increased in the medulla oblongata by lysophosphatidylcholine (LPC)-induced focal demyelination, but that of NSCs was not changed. The inhibition of vascular endothelial growth factor (VEGF)- and platelet-derived growth factor (PDGF)-signaling suppressed the proliferation of OPCs by LPC-induced demyelination. Thus, the present study indicates that resident OPCs contribute to focal remyelination and VEGF and PDGF signaling is required for the proliferation of OPCs in the medulla oblongata of the adult mouse.

    15 Jul. 2019, Journal of neuroimmunology, 332, 176 - 186, English, International magazine

    [Refereed]

  • Shohei Takagi, Eriko Furube, Yousuke Nakano, Mitsuhiro Morita, Seiji Miyata

    Microglia are the primary resident immune cells of the brain parenchyma and transform into the amoeboid form in the "activated state" under pathological conditions from the ramified form in the "resting state" under physiologically healthy conditions. In the present study, we found that microglia in the circumventricular organs (CVOs) of adult mice displayed the amoeboid form with fewer branched cellular processes even under normal conditions; however, those in other brain regions showed the ramified form, which is characterized by well-branched and dendritic cellular processes. Moreover, microglia in the CVOs showed the strong protein expression of the M1 markers CD16/32 and CD86 and M2 markers CD206 and Ym1 without any pathological stimulation. Thus, the present results indicate that microglia in the CVOs of adult mice are morphologically and functionally activated under normal conditions, possibly due to the specialized features of the CVOs, namely, the entry of blood-derived molecules into parenchyma through fenestrated capillaries and the presence of neural stem cells.

    15 Jun. 2019, Journal of neuroimmunology, 331, 74 - 86, English, International magazine

    [Refereed]

  • Morita M, Ikeshima-Kataoka H, Kreft M, Vardjan N, Zorec R, Noda M

    Feb. 2019, International journal of molecular sciences, 20 (4)

    [Refereed]

  • Daishi Hiratsuka, Eriko Furube, Katsutoshi Taguchi, Masaki Tanaka, Mitsuhiro Morita, Seiji Miyata

    Experimental autoimmune encephalomyelitis (EAE) is primarily used as an animal model of autoimmune demyelinating disease, multiple sclerosis. In this study, we found the proliferative rate of oligodendrocyte progenitor cells (OPCs) in the medulla elevated twofold above control levels during EAE and new generation of mature oligodendrocytes was increased as well. Although astrocytes showed hypertrophic reactive phenotype, a new generation of them was rare. Astrocyte- and tanycyte-like neural stem cells (NSCs), multipotent NSCs, did not augment their low proliferative rate. Thus, the present study demonstrates that resident OPCs derived from NSCs contribute to remyelination in the medulla oblongata in EAE mice.

    15 Jun. 2018, Journal of neuroimmunology, 319, 41 - 54, English, International magazine

    [Refereed]

    Scientific journal

  • Satoko Ueno, Hiroshi Miyoshi, Yoko Maruyama, Mitsuhiro Morita, Shohei Maekawa

    Neurons have well-developed membrane microdomains called “rafts” that are recovered as a detergent-resistant low-density membrane microdomain fraction (DRM). NAP-22 is one of the major protein components of neuronal DRM and localizes in the presynaptic region. In order to know the role of NAP-22 in the synaptic transmission, NAP-22 binding proteins in the cytosol were searched with an affinity screening with NAP-22 as a bait and several protein bands were detected. Using mass-analysis and western blotting, one of the main band of ∼90 kDa was identified as dynamin I. The GTPase activity of dynamin I was partly inhibited by NAP-22 expressed in bacteria and this inhibition was recovered by the addition of calmodulin, a NAP-22 binding protein. The GTPase activity of dynamin was known to be activated with acidic membrane lipids such as phosphatidylserine and the addition of NAP-22, a phosphatidylserine binding protein, inhibited the activation of the GTPase by this lipid. Since NAP-22 localizes on the presynaptic plasma membrane and on synaptic vesicles, these results suggest the participation of NAP-22 in the membrane cycling through binding to dynamin and acidic membrane lipids at the presynaptic region.

    Elsevier Ireland Ltd, 14 May 2018, Neuroscience Letters, 675, 59 - 63, English

    [Refereed]

    Scientific journal

  • Ueno, S, Miyoshi, H, Maruyama, Y, Morita, M, Maekawa, S

    May 2018, International Journal of Lipids, 1 (1), 1 - 10, English

    [Refereed]

    Scientific journal

  • Yoko Maruyama, Satoko Ueno, Mitsuhiro Morita, Fumio Hayashi, Shohei Maekawa

    Neurons have well-developed membrane microdomains called “rafts” that are recovered as a detergent-resistant membrane microdomain fraction (DRM). NAP-22 is one of the major protein components of neuronal DRM. In a previous study, we showed that DRM-derived NAP-22 binds ganglioside and the inhibitory effect of ganglioside to calcineurin (CaN), a neuron-enriched calmodulin-regulated phosphoprotein phosphatase. Considering the important roles of CaN in neurons, identification of other cellular regulators of CaN could be a good clue to understand the molecular background of neuronal function. In this study, we screened the effect of several membrane lipid-derived molecules on the CaN activity and found sphingosine and some sphingosine-derived metabolites such as sphingosylphosphorylcholine, galactosylsphingosine (psychosine), and glucosylsphingosine, have inhibitory effect on CaN through the interaction with calmodulin.

    Elsevier Ireland Ltd, 23 Apr. 2018, Neuroscience Letters, 673, 132 - 135, English

    [Refereed]

    Scientific journal

  • Sakai Y, Asakura, Y, Morita, M, Takahashi, T

    Dec. 2017, Chem. Pharm. Bull, 65 (12), 1195 - 1198, English

    [Refereed]

    Scientific journal

  • Yuki Fujii, Shohei Maekawa, Mitsuhiro Morita

    Wave-like propagation of [Ca2+](i) increases is a remarkable intercellular communication characteristic in astrocyte networks, intercalating neural circuits and vasculature. Mechanically-induced [Ca2+](i) increases and their subsequent propagation to neighboring astrocytes in culture is a classical model of astrocyte calcium wave and is known to be mediated by gap junction and extracellular ATP, but the role of each pathway remains unclear. Pharmacologic analysis of time-dependent distribution of [Ca2+](i)revealed three distinct [Ca2+](i) increases, the largest being in stimulated cells independent of extracellular Ca2+ and inositol 1,4,5-trisphosphate-induced Ca2+ release. In addition, persistent [Ca2+](i) increases were found to propagate rapidly via gap junctions in the proximal region, and transient [Ca2+](i) increases were found to propagate slowly via extracellular ATP in the distal region. Simultaneous imaging of astrocyte [Ca2+](i) and extracellular ATP, the latter of which was measured by an ATP sniffing cell, revealed that ATP was released within the proximal region by volume-regulated anion channel in a [Ca2+](i) independent manner. This detailed analysis of a classical model is the first to address the different contributions of two major pathways of calcium waves, gap junctions and extracellular ATP.

    NATURE PUBLISHING GROUP, Oct. 2017, SCIENTIFIC REPORTS, 7 (1), 13115, English

    [Refereed]

    Scientific journal

  • Kunihiko Yamashiro, Mitsuhiro Morita

    Adenosine modulates diverse physiological and pathological processes in the brain, including neuronal activities, blood flow, and inflammation. However, the mechanisms underlying the dynamics of extracellular adenosine are not fully understood. We have recently developed a novel biosensor, called an adenosine sensor cell, and we have characterized the neuronal and astrocytic pathways for elevating extracellular adenosine. In this review, the physiological implications and therapeutic potential of the pathways revealed by the adenosine sensor cells are discussed. We propose that the multiple pathways regulating extracellular adenosine allow for the diverse functions of this neuromodulator, and their malfunctions cause various neurological and psychiatric disorders.

    MEDKNOW PUBLICATIONS & MEDIA PVT LTD, Jun. 2017, NEURAL REGENERATION RESEARCH, 12 (6), 881 - 885, English

    [Refereed]

  • Kunihiko Yamashiro, Yuki Fujii, Shohei Maekawa, Mitsuhiro Morita

    Extracellular adenosine in the brain, which modulates various physiological and pathological processes, fluctuates in a complicated manner that reflects the circadian cycle, neuronal activity, metabolism, and disease states. The dynamics of extracellular adenosine in the brain are not fully understood, largely because of the lack of simple and reliable methods of measuring time-dependent changes in tissue adenosine distribution. This study describes the development of a biosensor, designated an adenosine sensor cell, expressing adenosine A1 receptor, and a genetically modified G protein. This biosensor was used to characterize extracellular adenosine elevation in brain tissue by measuring intracellular calcium elevation in response to adenosine. Placement of adenosine sensor cells below hippocampal slices successfully detected adenosine releases from these slices in response to neuronal activity and astrocyte swelling by conventional calcium imaging. Pharmacological analyses indicated that high-frequency electrical stimulation-induced post-synaptic adenosine release in a manner dependent on L-type calcium channels and calcium-induced calcium release. Adenosine release following treatments that cause astrocyte swelling is independent of calcium channels, but dependent on aquaporin 4, an astrocyte-specific water channel subtype. The ability of ectonucleotidase inhibitors to inhibit adenosine release following astrocyte swelling, but not electrical stimulation, suggests that the former reflects astrocytic ATP release and subsequent enzymatic breakdown, whereas the latter reflects direct adenosine release from neurons. These results suggest that distinct mechanisms are responsible for extracellular adenosine elevations by neurons and astrocytes, allowing exquisite regulation of extracellular adenosine in the brain.

    WILEY-BLACKWELL, Jan. 2017, JOURNAL OF NEUROCHEMISTRY, 140 (1), 24 - 36, English

    [Refereed]

    Scientific journal

  • Eriko Furube, Mitsuhiro Morita, Seiji Miyata

    Although evidence has accumulated that neurogenesis and gliogenesis occur in the subventricular zone (SVZ) and subgranular zone (SGZ) of adult mammalian brains, recent studies indicate the presence of neural stem cells (NSCs) in adult brains, particularly the circumventricular regions. In the present study, we aimed to determine characterization of NSCs and their progenitor cells in the sensory circumventricular organs (CVOs), including organum vasculosum of the lamina terminalis, subfornical organ, and area postrema of adult mouse. There were two types of NSCs: tanycyte-like ependymal cells and astrocyte-like cells. Astrocyte-like NSCs proliferated slowly and oligodendrocyte progenitor cells (OPCs) and neural progenitor cells (NPCs) actively divided. Molecular marker protein expression of NSCs and their progenitor cells were similar to those reported in the SVZ and SGZ, except that astrocyte-like NSCs expressed S100 beta. These circumventricular NSCs possessed the capacity to give rise to oligodendrocytes and sparse numbers of neurons and astrocytes in the sensory CVOs and adjacent brain regions. The inhibition of vascular endothelial growth factor (VEGF) signaling by using a VEGF receptor-associated tyrosine kinase inhibitor AZD2171 largely suppressed basal proliferation of OPCs. A single systemic administration of lipopolysaccharide attenuated proliferation of OPCs and induced remarkable proliferation of microglia. The present study indicates that sensory circumventricular NSCs provide new neurons and glial cells in the sensory CVOs and adjacent brain regions.

    SPRINGER, Nov. 2015, CELL AND TISSUE RESEARCH, 362 (2), 347 - 365, English

    [Refereed]

    Scientific journal

  • Kobayashi, Y, Ronan da Silva, Kumanogoh, H, Miyata, S, Sato, C, Kitajima, K, Nakamura, S, Morita, M, Hayashi, F, Maekawa, S

    Sep. 2015, J Neurosci Res, 98 (9), 1462 - 1470, English

    [Refereed]

    Scientific journal

  • Mitsuhiro Morita, Akira Nakane, Shohei Maekawa, Yoshihisa Kudo

    Evidence increasingly shows that astrocytes play a pivotal role in brain physiology and pathology via calcium dependent processes, thus the characterization of the calcium dynamics in astrocytes is of growing importance. We have previously reported that the epidermal growth factor and basic fibroblast growth factor up-regulate the oscillation of the calcium releases that are induced by stimuli, including glutamate in cultured astrocytes. This calcium oscillation is assumed to involve protein kinase C (PKC), which is activated together with the calcium releases as a consequence of inositol phospholipid hydrolysis. In the present study, this issue has been investigated pharmacologically by using astrocytes cultured with and without the growth factors. The pharmacological activation of PKC largely reduced the glutamate-induced oscillatory and non-oscillatory calcium increases. Meanwhile, PKC inhibitors increased the total amounts of both calcium increases without affecting the peak amplitudes and converted the calcium oscillations to non-oscillatory sustained calcium increases by abolishing the falling phases of the repetitive calcium increases. Furthermore, the pharmacological effects were consistent between both glutamate-and histamine-induced calcium oscillations. These results suggest that PKC up-regulates the removal of cytosolic calcium in astrocytes, and this up-regulation is essential for calcium oscillation in astrocytes cultured with growth factors. (C) 2015 Japanese Pharmacological Society.

    JAPANESE PHARMACOLOGICAL SOC, Sep. 2015, JOURNAL OF PHARMACOLOGICAL SCIENCES, 129 (1), 38 - 42, English

    [Refereed]

    Scientific journal

  • Mitsuhiro Morita, Akira Nakane, Yuki Fujii, Shohei Maekawa, Yoshihisa Kudo

    Calcium releases of non-excitable cells are generally a combination of oscillatory and non-oscillatory patterns, and factors affecting the calcium dynamics are still to be determined. Here we report the influence of cell density on calcium increase patterns of clonal cell lines. The majority of HeLa cells seeded at 1.5 x 10(4)/cm(2) showed calcium oscillations in response to histamine and ATP, whereas cells seeded at 0.5 x 10(4)/cm(2) largely showed transient and sustained calcium increases. Cell density also affected the response of HEK293 cells to ATP in a similar manner. High cell density increased the basal activity of the mitogen-activated protein ( MAP) kinase and calcium store content, and both calcium oscillation and calcium store content were down-regulated by a MAP kinase inhibitor, U0126. Thus, MAP kinase-mediated regulation of calcium store likely underlie the effect of cell density on calcium oscillation. Calcium increase patterns of HeLa cells were conserved at any histamine concentrations tested, whereas the overexpression of histamine H1 receptor, which robustly increased histamine-induced inositol phospholipid hydrolysis, converted calcium oscillations to sustained calcium increases only at high histamine concentrations. Thus, the consequence of modulating inositol phospholipid metabolism was distinct from that of changing cell density, suggesting the effect of cell density is not attributed to inositol phospholipid metabolism. Collectively, our results propose that calcium increase patterns of non-excitable cells reflect calcium store, which is regulated by the basal MAP kinase activity under the influence of cell density.

    PUBLIC LIBRARY SCIENCE, Sep. 2015, PLOS ONE, 10 (9), e0137610, English

    [Refereed]

    Scientific journal

  • Shohei Maekawa, Yuumi Kobayashi, Mitsuhiro Morita, Toshinobu Suzaki

    Recovery of various signal transduction molecules in the detergent-resistant membrane microdomain (DRM) fraction suggests the importance of this region in cellular functions. Insolubility of the outer leaflet of DRM to the non-ionic detergent is ascribed to the tight association of cholesterol and sphingolipid. Since, poor localization of sphingolipid is observed in the inner leaflet, the physicochemical background of the insolubility of the inner leaflet is hence still an enigma. NAP-22 (also called BASP1 or CAP-23) is a neuron-enriched calmodulin-binding protein and one of the major proteins in the DRM of the neuronal cell membrane. A previous study showed the presence of several lipids in a NAP-22 fraction after the process of extraction and column chromatography. In this study, the effect of lipid extraction on NAP-22 was studied through native-gel electrophoresis, ultracentrifugation, and electron microscopic observation. The mobility of NAP-22 in native-PAGE was shifted from low to high after delipidation. Delipidated NAP-22 bound phosphatidylserine (PS), phosphatidylinosotol, and ganglioside. Some part of the mixture of PS and NAP-22 was recovered in the insoluble fraction after Triton X-100 treatment and the addition of cholesterol enhanced the amount of NAP-22 in the insoluble fraction. (C) 2015 Elsevier Ireland Ltd. All rights reserved.

    ELSEVIER IRELAND LTD, Jul. 2015, NEUROSCIENCE LETTERS, 600, 244 - 248, English

    [Refereed]

    Scientific journal

  • Shohei Maekawa, Yuumi Kobayashi, Sin-Ichi Odagaki, Midori Makino, Haruko Kumanogoh, Shun Nakamura, Mitsuhiro Morita, Fumio Hayashi

    NAP-22 (also called BASP1 or CAP-23) is a neuron-enriched protein localized mainly in the synaptic vesicles and the synaptic plasma membrane. Biochemically, it is recovered in the lipid raft fraction. In order to understand the physiological function of the neuronal lipid raft, NAP-22 binding proteins were screened with a pull-down assay. Glutamic acid decarboxylase (GAD) was detected through LC-MS/MS, and Western blotting using a specific antibody confirmed the result. Two isoforms of GAD, GAD65 and GAD67, were expressed in bacteria as GST-fusion forms and the interaction with NAP-22 was confirmed in vitro. Partial co-localization of NAP-22 with GAD65 and GAD67 was also observed in cultured neurons. The binding showed no effect on the enzymatic activity of GAD65 and GAD67. These results hence suggest that NAP-22 could participate in the transport of GAD65 and GAD67 to the presynaptic termini and their retention on the synaptic vesicles as an anchoring protein. (c) 2013 Elsevier Ireland Ltd. All rights reserved.

    ELSEVIER IRELAND LTD, Mar. 2013, NEUROSCIENCE LETTERS, 537, 50 - 54, English

    [Refereed]

    Scientific journal

  • Maowulan Maimaitiyiming, Haruko Kumanogoh, Shun Nakamura, Mitsuhiro Morita, Shohei Maekawa

    Septin forms a conserved family of cytoskeletal GTP-binding proteins that have diverse roles in protein scaffolding, vesicle trafficking and cytokinesis. There are 14 mammalian septin isoforms and these isoforms assemble into hetero-oligomeric rod-shaped complexes and these short filaments are the basal units to construct higher-order structures such as longer filaments, rings, gauzes or hourglasses. Septin expressed in a eukaryotic expression system forms various structures such as bundles, sheets, helixes, and rings. Septin expressed in bacteria formed hexameric short filaments and single or parallel long filaments, but no such higher order structures were observed so far. In a previous study, we showed maturation-dependent localization of septin isoforms to the lipid raft fraction of rat brain. In this study, we attempted further purification of raft-localized septin isoforms. Repeated cycles of extraction with high MgCl2 solution and precipitation under low ionic solution were combined with several column procedures. The obtained fraction contained several septin isoforms and showed rings of bundled filaments with a diameter of ∼0.4 μm. Several non-septin proteins were also detected in the fraction. We also attempted expression of septin isoforms in bacteria and found that the expressed septin complexes formed bundles of filaments. In addition to linear and curled filaments, circular bundles of thin filaments with a diameter of ∼0.6 μm were also observed. These results suggest that the curvature of the bundles of septin filaments may be regulated by the regulatory factor(s) in the lipid raft.

    Academic Press Inc., 01 Feb. 2013, Protein Expression and Purification, 87 (2), 67 - 71, English

    [Refereed]

    Scientific journal

  • Maowulan Maimaitiyiming, Yuumi Kobayashi, Haruko Kumanogoh, Shun Nakamura, Mitsuhiro Morita, Shohei Maekawa

    Lipid rafts (detergent-resistant low-density membrane microdomain: DRM) are signal-transducing membrane platforms. In a previous study, we showed maturation-dependent localization of septin in the DRM fraction of rat brain. Mammalian septin is composed with 13-14 isoforms and these isoforms assemble to form rod-shaped hetero-oligomeric complexes. End-to-end polymerization of these complexes results in the formation of higher order structures such as filamentous sheets or bundles of filaments that restrict the fluid-like diffusion of the membrane proteins and lipids. Considering the function of septin as the membrane scaffold, elucidation of the molecular interaction of septin in DRM could be a breakthrough to understand another role of lipid rafts. In order to identify septin-binding proteins in DRM, solubilization and fractionation of septin from DRM was attempted. Several proteins were co-fractionated with septin and LC-MS/MS analysis identified one of these proteins as dynamin and Western blotting using anti-dynamin confirmed this result. Immunoprecipitation of septin11 in a crude supernatant showed co-precipitation of dynamin and dynamin fraction prepared from brain contained several septin isoforms. Within bacterially expressed septin isoforms, septin5 and septin11 bound dynamin but septin9 did not. These results suggest that some septin isoforms participate in the dynamin-related membrane dynamics. (C) 2012 Elsevier Ireland Ltd. All rights reserved.

    ELSEVIER IRELAND LTD, Feb. 2013, NEUROSCIENCE LETTERS, 534, 322 - 326, English

    [Refereed]

    Scientific journal

  • Takayuki Suzuki, Honami Sakata, Chiaki Kato, John A. Connor, Mitsuhiro Morita

    Localised brain tissue damage activates surrounding astrocytes, which significantly influences subsequent long-term pathological processes. Most existing focal brain injury models in rodents employ craniotomy to localise mechanical insults. However, the craniotomy procedure itself induces gliosis. To investigate perilesional astrocyte activation under conditions in which the skull is intact, we created focal brain injuries using light exposure through a cranial window made by thinning the skull without inducing gliosis. The lesion size was maximal at similar to 12 h and showed substantial recovery over the subsequent 30 days. Two distinct types of perilesional reactive astrocyte, identified by GFAP upregulation and hypertrophy, were found. In proximal regions the reactive astrocytes proliferated and expressed nestin, whereas in regions distal to the injury core the astrocytes showed increased GFAP expression but did not proliferate, lacked nestin expression, and displayed different morphology. Simply making the window did not induce any of these changes. There were also significant numbers of neurons in the recovering cortical tissue. In the recovery region, reactive astrocytes radially extended processes which appeared to influence the shapes of neuronal nuclei. The proximal reactive astrocytes also formed a cell layer which appeared to serve as a protective barrier, blocking the spread of IgG deposition and migration of microglia from the lesion core to surrounding tissue. The recovery was preceded by perilesional accumulation of leukocytes expressing vascular endothelial growth factor. These results suggest that, under intact skull conditions, focal brain injury is followed by perilesional reactive astrocyte activities that foster cortical tissue protection and recovery.

    WILEY, Dec. 2012, EUROPEAN JOURNAL OF NEUROSCIENCE, 36 (12), 3653 - 3664, English

    [Refereed]

    Scientific journal

  • Rika Takaichi, Sin-Ichi Odagaki, Haruko Kumanogoh, Shun Nakamura, Mitsuhiro Morita, Shohei Maekawa

    Endocytosis of the synaptic vesicle is a complicated process, in which many proteins and lipids participate. Phosphatidylinositol 4,5-bisphosphate (PIP2) plays important roles in the process, and the dynamic regulation of this lipid is one of the key events. Synaptojanin is a PIP2 phosphatase, and dephosphorylation of PIP2 of the clathrin coated-vesicle results in the uncoating of the vesicle. NAP-22 is one of the major proteins of the neuronal detergent-resistant membrane microdomain and localizes in both the presynaptic plasma membrane and the synaptic vesicle. To elucidate the role of NAP-22 in synaptic function, a screening of the NAP-22 binding proteins through pull-down assay was performed. In addition to CapZ protein, synaptojanin-1 was detected by LC-MS/MS, and Western blotting using antisynaptojanin-1 confirmed this result. The interaction seems to be important in the course of synaptic vesicle endocytosis, because NAP-22 inhibited the phosphatase activity of synaptojanin in a dose-dependent manner. The inhibitory region for 5-phosphatase and the binding region for PIP2 overlapped in the amino acid sequence of NAP-22, so elucidation of the regulatory mechanism of the PIP2 binding ability of NAP-22 could be important in understanding the membrane dynamics at the presynaptic region. (c) 2011 Wiley Periodicals, Inc.

    WILEY-BLACKWELL, Jan. 2012, JOURNAL OF NEUROSCIENCE RESEARCH, 90 (1), 21 - 27, English

    [Refereed]

    Scientific journal

  • Mitsuhiro Morita, Yoshihisa Kudo

    Previously, we reported upregulation of astrocyte [Ca2+](i) oscillation by growth factors (i.e., conversion of glutamate-induced sustained [Ca2+] increase in astrocytes cultured in a defined medium to [Ca2+](i) oscillation by EGF and bFGF treatment over 48 h) (Morita et al., (2003) J Neurosci 23:10944-10952). As our previous study also showed that these growth factors increase intracellular Ca2+ stores, this study was performed to investigate the mechanism underlying loading of intracellular Ca2+ stores in astrocytes, especially sarco-endoplasmic reticulum Ca2+ ATPase (SERCA), as a candidate mechanism by which growth factors upregulate [Ca2+](i) oscillation. The results indicated that the growth factors upregulated a SERCA inhibitor-sensitive component of [Ca2+](i) clearance, and increased expression of the SERCA subtype, SERCA2b. Furthermore, treating the growth factor-treated astrocytes with a low concentration of SERCA inhibitor to partially inhibit SERCA reduced the level of intracellular Ca2+ storage and reversed glutamate-induced [Ca2+](i) oscillations to sustained [Ca2+](i) increases. Thus, the upregulation of [Ca2+](i) oscillations was attributed to the upregulation of SERCA activities. These results indicated that these growth factors regulate the pattern of glutamate-induced astrocyte [Ca2+](i) increases via SERCA2b expression. (C) 2010 Wiley-Liss, Inc.

    WILEY-BLACKWELL, Dec. 2010, GLIA, 58 (16), 1988 - 1995, English

    [Refereed]

    Scientific journal

  • Masahiko Morita, Nobukazu Shitan, Keisuke Sawada, Marc C. E. Van Montagu, Dirk Inze, Heiko Rischer, Alain Goossens, Kirsi-Marja Oksman-Caldentey, Yoshinori Moriyama, Kazufumi Yazaki

    Alkaloids play a key role in plant defense mechanisms against pathogens and herbivores, but the plants themselves need to cope with their toxicity as well. The major alkaloid of the Nicotiana species, nicotine, is translocated via xylem transport from the root tissues where it is biosynthesized to the accumulation sites, the vacuoles of leaves. To unravel the molecular mechanisms behind this membrane transport, we characterized one transporter, the tobacco (Nicotiana tabacum) jasmonate-inducible alkaloid transporter 1 (Nt-JAT1), whose expression was coregulated with that of nicotine biosynthetic genes in methyl jasmonate-treated tobacco cells. Nt-JAT1, belonging to the family of multidrug and toxic compound extrusion transporters, was expressed in roots, stems, and leaves, and localized in the tonoplast of leaf cells. When produced in yeast cells, Nt-JAT1 occurred mainly in the plasma membrane and showed nicotine efflux activity. Biochemical analysis with proteoliposomes reconstituted with purified Nt-JAT1 and bacterial F(0)F(1)-ATPase revealed that Nt-JAT1 functioned as a proton antiporter and recognized endogenous tobacco alkaloids, such as nicotine and anabasine, and other alkaloids, such as hyoscyamine and berberine, but not flavonoids. These findings strongly suggest that Nt-JAT1 plays an important role in the nicotine translocation by acting as a secondary transporter responsible for unloading of alkaloids in the aerial parts and deposition in the vacuoles.

    NATL ACAD SCIENCES, Feb. 2009, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 106 (7), 2447 - 2452, English

    [Refereed]

    Scientific journal

  • Mitsuhiro Morita, Kotaro Yoshizaki, Akira Nakane, Yoshihisa Kudo

    Phosphoinositide-3 kinase (PI3K) and phospholipase C (PLC) utilize the same phosphoinositides as substrates to produce different signaling molecules. These enzymes are activated by a similar set of cell signaling mechanisms, i.e., tyrosine kinases and G proteins, and affect common cell functions, including proliferation, motility, and intracellular trafficking. Despite these similarities, the interplay between these enzymes is not well understood.. To address this issue, the effects of the PI3K inhibitor LY294002 on carbachol-induced calcium increase in PC12h cells were examined. As carbachol stimulates both Gq- and Gi-coupled muscarinic acetylcholine receptors (mAChRs), PI3K and PLC are activated simultaneously in this protocol. LY294002 was found to reduce the carbachol-induced calcium increase, and the reduction was attributed to suppression of calcium entry. As LY294002 did not affect either carbachol-induced calcium release or calcium entry induced by calcium store depletion, this agent was found to suppress calcium entry directly activated by mAChRs. Although PI3K was supposed to compete for substrates with PLC, the PI3K inhibitor did not enhance PLC-dependent cellular responses. As LY294002 was still effective by treating cells after carbachol stimulation, it is likely that this agent blocks the calcium entry channels directly.

    JAPANESE PHARMACOLOGICAL SOC, Nov. 2007, JOURNAL OF PHARMACOLOGICAL SCIENCES, 105 (3), 258 - 263, English

    [Refereed]

    Scientific journal

  • Mitsuhiro Morita, Fumito Yoshiki, Akira Nakane, Yoshiumi Okubo, Yoshihisa Kudo

    The production and further metabolism of inositol 1,4,5-trisphosphate [Ins(1,4,5)P-3] require several calcium-dependent enzymes, but little is known about subsequent calcium-dependent changes in cellular Ins(1,4,5)P-3. To study the calcium dependence of muscarinic acetylcholine receptor-induced Ins(1,4,5)P-3 increases in PC12h cells, we utilized an Ins(1,4,5)P-3 imaging system based on fluorescence resonance energy transfer and using green fluorescent protein variants fused with the pleckstrin homology domain of phospholipase C-delta 1. The intracellular calcium concentration, monitored by calcium imaging, was adjusted by thapsigargin pretreatment or alterations in extracellular calcium concentration, enabling rapid receptor-independent changes in calcium concentration via store-operated calcium influx. We found that Ins(1,4,5)P-3 production was increased by a combination of receptor- and calcium-dependent components, rather than by calcium alone. The level of Ins(1,4,5)P-3 induced by the receptor was found to be half that induced by the combined receptor and calcium components. Increases in calcium levels prior to receptor activation did not affect the subsequent receptor-induced Ins(1,4,5)P-3 increase, indicating that calcium does not influence Ins(1,4,5)P-3 production without receptor activation. Removal of both the receptor agonists and calcium rapidly restored calcium and Ins(1,4,5)P-3 levels, whereas removal of calcium alone restored calcium to its basal concentration. Similar calcium-dependent increases in Ins(1,4,5)P-3 were also observed in Chinese hamster ovary cells expressing m1 muscarinic acetylcholine receptor, indicating that the observed calcium dependence is common to Ins(1,4,5)P-3 production. To our knowledge, our results are the first showing receptor- and calcium-dependent components within cellular Ins(1,4,5)P-3.

    BLACKWELL PUBLISHING, Oct. 2007, FEBS JOURNAL, 274 (19), 5147 - 5157, English

    [Refereed]

    Scientific journal

  • K. B. Blagoev, B. Mihaila, B. J. Travis, L. B. Alexandrov, A. R. Bishop, D. Ranken, S. Posse, C. Gasparovic, A. Mayer, C. J. Aine, I. Ulbert, M. Morita, W. Muller, J. Connor, E. Halgren

    Neuronal communication in the brain involves electrochemical currents, which produce magnetic fields. Stimulus-evoked brain responses lead to changes in these fields and can be studied using magneto- and electro-encephalography (MEG/EEG). In this paper we model the spatiotemporal distribution of the magnetic field of a physiologically idealized but anatomically realistic neuron to assess the possibility of using magnetic resonance imaging (MRI) for directly mapping the neuronal currents in the human brain. Our results show that the magnetic field several centimeters from the centre of the neuron is well approximated by a dipole source, but the field close to the neuron is not, a finding particularly important for understanding the possible contrast mechanism underlying the use of MRI to detect and locate these currents. We discuss the importance of the spatiotemporal characteristics of the magnetic field in cortical tissue for evaluating and optimizing an experiment based on this mechanism and establish an upper bound for the expected MRI signal change due to stimulus-induced cortical response. Our simulations show that the expected change of the signal magnitude is 1.6% and its phase shift is 1 degrees. An unexpected finding of this work is that the cortical orientation with respect to the external magnetic field has little effect on the predicted MRI contrast. This encouraging result shows that magnetic resonance contrast directly based on the neuronal currents present in the cortex is theoretically a feasible imaging technique. MRI contrast generation based on neuronal currents depends on the dendritic architecture and we obtained high-resolution optical images of cortical tissue to discuss the spatial structure of the magnetic field in grey matter. Published by Elsevier Inc.

    ACADEMIC PRESS INC ELSEVIER SCIENCE, Aug. 2007, NEUROIMAGE, 37 (1), 137 - 148, English

    [Refereed]

    Scientific journal

  • Mitsuhiro Morita, Chihiro Saruta, Nagisa Kozuka, Yoshiumi Okubo, Makoto Itakura, Masami Takahashi, Yoshihisa Kudo

    Evidence that glutamate and ATP release from astrocytes can occur via gap junction hemichannels (GJHCs) is accumulating. However, the GJHC is still only one possible release mechanism and has not been detected in some studies, although this may be because the levels were below those detectable by the system used. Because of these conflicting results, we hypothesized that release from astrocyte GJHCs might depend on different astrocyte states, and screened for factors affecting astrocyte GJHC activity by measuring fluorescent dye leakage via GJHCs using a conventional method for GJHC acivation, i.e. removal of extracellular divalent cations. Astrocytes cultured in Dulbecco's minimal essential medium containing 10% fetal calf serum, a medium widely used for astrocyte studies, did not show dye leakage, whereas those cultured in a defined medium showed substantial dye leakage, which was confirmed pharmacologically to be due to GJHCs and not to P2x7 receptors. EGF and bFGF inhibited the GJHC activity via the mitogen-activated protein kinase cascade, and the effect of the growth factors was reversed by interleukin-1 beta. These factors altered GJHC activity within 10 min, but did not affect connexin 43 expression. GJHC activity in hippocampal slice culture preparations was measured using the same methods and found to be regulated in a similar manner. These results indicate that astrocyte GJHC activity is regulated by brain environmental factors. (c) 2007 Wiley-Liss, Inc.

    WILEY-LISS, Apr. 2007, GLIA, 55 (5), 508 - 515, English

    [Refereed]

    Scientific journal

  • Kozuka, N, Kudo, Y, Morita, M

    Feb. 2007, Neuroscience, 144 (3), 911 - 919, English

    [Refereed]

    Scientific journal

  • Yoshitoku Yoshida, Haruno Kumagai, Yoshiumi Ohkubo, Remi Tsuchiya, Mitsuhiro Morita, Hiroyoshi Miyakawa, Yoshihisa Kudo

    The effect of bifemelane hydrochloride (bifemelane) was examined on human origin astrocyte clonal cells (Kings-1). Bifemelane (125 - 1000 mu M) induced a dose-dependent increase in the intracellular calcium concentration ([Ca2+](i)). In the highest concentration (1000 mu M), the drug caused the second large increase in [Ca2+](i) during the washing. The increase that occurred during the administration partially remained in the Ca2+-free medium and was blocked by 2-aminoethoxydiphenyl borate (2-APB), an IP3-receptor blocker, indicating that the source of Ca2+ for the increase could be ascribed to the intracellular store. The increase in [Ca2+](i) was not observed during washing with Ca2+-free medium, but was observed when the washing was performed with Ca2+-containing medium. Bifemelane caused a dose-dependent ATP release, but histamine and carbachol, which induced a large increase in [Ca2+](i), had no effects on the ATP release. The effects on the [Ca2+](i) were blocked by pretreatment with pyridoxal phosphate-6-azophenyl-2',4' disulfonic acid, a P2-receptor antagonist. Although the mechanisms of ATP release induced by the drug have not been elucidated yet, the present results demonstrate that the increase in [Ca2+](i) induced by bifemelane is not due to its direct effect on the cells, but is dependent upon the ATP released from the cells.

    JAPANESE PHARMACOLOGICAL SOC, Sep. 2006, JOURNAL OF PHARMACOLOGICAL SCIENCES, 102 (1), 121 - 128, English

    [Refereed]

    Scientific journal

  • M Hirabayashi, M Kato, R Kaneko, T Hirabayashi, M Morita, S Hochi

    It was reported that recombinase-A protein (RecA)-coated exogenous DNA was more likely to be integrated into mouse, goat and pig genomes. The objective of this study was to investigate whether integration of exogenous DNA into the rat genome is improved by the recombinase-mediated DNA transfer. Pronuclear microinjection of RecA-coated EGFP or OAMB DNA resulted in a production efficiency of transgenic rats of 1.4-2.9%, comparable with 0.9-2.6% when non-coated control DNA was used. Intracytoplasmic injection of the sperm heads exposed to RecA-coated EGFP DNA did not produce any transgenic rats (0 vs. 0-2.8% in control groups). Thus, the recombinase-mediated DNA transfer contributed very little to the production of transgenic rats by means of pronuclear microinjection and intracytoplasmic sperm injection.

    INT PRESS EDITING CENTRE INC, Apr. 2006, EXPERIMENTAL ANIMALS, 55 (2), 131 - 135, English

    [Refereed]

    Scientific journal

  • Y Yoshida, A Nakane, M Morita, Y Kudo

    We investigated the effects of bifemelane, a nootropic drug, on the intracellular calcium concentration ([Ca2+](i)) in rat cerebral astrocytes using a Ca2+ imaging device. At concentrations of 10-30 mu M, bifemelane induced a slow onset and small increase in the [Ca2+], while at higher concentrations (100-300 mu M), it induced a rapid transient increase in the [Ca2+], during administration and a second large increase was seen during drug washout. The first peak was observed in Ca2+-free medium, but its onset was significantly delayed, and no second peak was seen. Neither of these effects was seen in cells treated with thapsigargin, a specific inhibitor of endoplasmic reticulum Ca2+-ATPase, in Ca2+-free medium. When thapsigargintreated astrocytes were returned to normal medium containing Ca2+ (1.8 mM), the [Ca2+](i) increased significantly, and this effect was reversely inhibited by bifemelane. We conclude that bifemelane causes the first peak by stimulating release from intracellular Ca2+ stores and the second by capacitive entry through store-operated Ca2+. channels. Although the detail mechanisms of action of the drug are still unknown, bifemelane will be provided as a pharmacological tool for basic studies on astrocytes.

    JAPANESE PHARMACOLOGICAL SOC, Feb. 2006, JOURNAL OF PHARMACOLOGICAL SCIENCES, 100 (2), 126 - 132, English

    [Refereed]

    Scientific journal

  • M Morita, J Susuki, H Amino, F Yoshiki, S Moizumi, Y Kudo

    Diverse excitatory and inhibitory neuronal responses are mediated via Gq-coupled receptors, but the lack of a systematic comparison of different receptors or neurons has hindered a better understanding of these responses. Such a comparison may be provided by an exogenous receptor that is activated by compounds that have no effect on endogenous receptors. We therefore expressed an invertebrate biogenic amine receptor, the Drosophila octopamine receptor, in rat cortical neurons and compared octopamine receptor-mediated responses with those mediated by the group I metabotropic glutamate receptor, the endogenous Gq-coupled receptor in rat cortical neurons. Stimulation of either receptor did not result in a calcium response in octopamine receptor-expressing neurons, although octopamine preferentially elicited a calcium increase in octopamine receptor-expressing PC12h cells, while enhancing the neuronal depolarization-induced calcium increase and the electrical excitability. The increased excitability was caused by inward currents resulting from a reduction in the leak current, which was voltage-independent and blocked by genistein, a non-selective tyrosine kinase inhibitor. These results show that, in cortical neurons, exogenous octopamine receptor in mushroom bodies activated the same cell signaling pathway as endogenous metabotropic glutamate receptor, suggesting that the diverse neuronal responses mediated by Gq-coupled receptors are due to the properties of different neurons, rather than to the properties of the receptors. (c) 2005 IBRO. Published by Elsevier Ltd. All rights reserved.

    PERGAMON-ELSEVIER SCIENCE LTD, 2006, NEUROSCIENCE, 137 (2), 545 - 553, English

    [Refereed]

    Scientific journal

  • N Kozuka, R Itofusa, Y Kudo, M Morita

    Nitric oxide (NO) production by astrocytes is a significant factor affecting brain physiology and pathology, but the mechanism by which it is regulated is not known. Previous studies using different specimens and stimuli might have described different aspects of a complex system. We investigated the effect of culture and stimulus conditions on NO production by cultured astrocytes and identified two combinations of these allowing NO production. Lipopolysaccharide (LPS)-induced NO production required a high seeding cell density and was independent of the serum concentration, whereas that induced by proinflammatory cytokines required simultaneous treatment with interleukin-1 beta, tumor necrosis factor-alpha, and interferon-gamma and low-serum conditions but was less affected by the seeding density. These two pathways showed differential sensitivity to protein kinase inhibitors. Both LPS and cytokines induced expression of inducible nitric oxide synthase (NOS). Although LPS-induced NOS expression required a high seeding cell density, cytokine-incluced NOS expression, in contrast to NO production, was not affected by the serum concentration. These results suggest that astrocytes interact with the environment and alter their responsiveness to NO production-inducing stimuli by regulating NOS expression and activity. This is the first evidence for the selective use of two different regulatory pathways in any cell type. (c) 2005 Wiley-Liss, Inc.

    WILEY-LISS, Dec. 2005, JOURNAL OF NEUROSCIENCE RESEARCH, 82 (5), 717 - 728, English

    [Refereed]

    Scientific journal

  • M Morita, N Kozuka, R Itofusa, M Yukawa, Y Kudo

    We previously reported that astrocytes cultured for more than 2 days in a defined medium containing epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) showed calcium oscillation in response to glutamate, whereas the response pattern was transient in the absence of the exogenous growth factors. In the present study, we found that astrocytes showed glutamate-induced calcium oscillation, even in growth factor-free medium, if the cells had been cultured for more than 5 days. The calcium oscillation promoted by the prolonged culture period was suppressed by an inhibitor of EGF receptor tyrosine kinase, but not by a neutralizing antibody to bFGF, indicating that the accumulation of an autocrine factor that activates the EGF receptor leads to calcium oscillation. Astrocytes in our culture system expressed EGF, transforming growth factor alpha (TGF alpha), bFGF and acidic fibroblast growth factor (aFGF). Exogenous aFGF, which induced astrocyte immediate early gene expression to the same extent as EGF or bFGF, did not affect calcium oscillation. Exogenous EGF and bFGF promoted astrocyte hypertrophic morphology and proliferation, as well as calcium oscillation. In contrast, these properties did not accompany calcium oscillation induced by the prolonged culture period. These results suggest that astrocytes possess the ability to promote their own calcium oscillation, which is independent of hypertrophic changes to reactive astrocytes.

    WILEY-BLACKWELL, Nov. 2005, JOURNAL OF NEUROCHEMISTRY, 95 (3), 871 - 879, English

    [Refereed]

    Scientific journal

  • M Nakahara, M Shimozawa, Y Nakamura, Y Irino, M Morita, Y Kudo, K Fukami

    Twelve phospholipase C ( PLC) isozymes have been cloned so far, and they are divided into six classes, beta-, gamma-, delta-, is an element of-, zeta-, and eta- type, on the basis of structure and activation mechanisms. Here we report the identification of a novel PLC isozyme, PLC eta 2. PLC eta 2 is composed of conserved domains including pleckstrin homology, EF-hand, X and Y catalytic, and C2 domains and the isozyme-specific C-terminal region. PLC eta 2 consists of 1164 amino acids with a molecular mass of 125 kDa. The PLC activity of PLC eta 2 was more sensitive to calcium concentration than the PLC activity of the PLC delta-type enzyme, which is thought to be the most calcium-sensitive PLC. Immunofluorescence analysis showed that PLC eta 2 was localized predominantly to the plasma membrane at resting state via the pleckstrin homology domain. This observation was supported by Western blot analysis of cytosol and membrane fractions. In addition, expression of PLC eta 2 was detected after birth and showed a restricted distribution in the brain; it was particularly abundant in the hippocampus, cerebral cortex, and olfactory bulb. The pattern was similar to that of the neuronal marker microtubule-associated protein by Western blot. Furthermore, in situ hybridization showed positive signals for PLC eta 2 in pyramidal cells of the hippocampus. Finally, we found that PLC eta 2 was expressed abundantly in neuron-containing primary culture but not in astrocyte-enriched culture. These results indicate that PLC eta 2 is a neuron-specific isozyme that may be important for the formation and/or maintenance of the neuronal network in the postnatal brain.

    AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC, Aug. 2005, JOURNAL OF BIOLOGICAL CHEMISTRY, 280 (32), 29128 - 29134, English

    [Refereed]

    Scientific journal

  • Y Yoshida, R Tsuchiya, N Matsumoto, M Morita, H Miyakawa, Y Kudo

    We have investigated whether the intracellular calcium concentration ([Ca2+](i)) oscillations induced in astrocytes using the metabotropic glutamate-receptor agonist, (IS,3R)-1-aminocyclopentane-1,3-dicarboxylic acid (t-ACPD) are Ca2+-dependent, using three different Ca2+ indicators with different affinities for Ca2+. When rat hippocampal cells in culture were loaded with fura-2 (K-d: 145 nM), two-thirds of the cells showed obvious oscillatory increase in [Ca2+](i) during t-ACPD-administration. Those cells were identified as astrocytes by immunohistochernistry in our previous paper. In cells loaded with fura-2FF (K-d: 25,000 nM), a similar percentage of t-ACPD-responsive cells showed oscillatory [Ca2+](i), changes. However, in cells loaded with quin-2 (K-d: 60 nM), t-ACPD induced no oscillatory responses, but some cells showed a small transient increase in the [Ca2+](i). The same small transient [Ca2+](i) increase was seen in cells loaded with both fura-2FF and BAPTA, a Ca2+ chelator (K-d: 135 nM). These findings indicate the involvement of [Ca2+](i)-dependent regulatory mechanisms in the induction of the t-ACPD-induced oscillatory change in the [Ca2+](i) in astrocytes.

    JAPANESE PHARMACOLOGICAL SOC, Feb. 2005, JOURNAL OF PHARMACOLOGICAL SCIENCES, 97 (2), 212 - 218, English

    [Refereed]

    Scientific journal

  • [Current calcium imaging systems].

    Kudo Y, Morita M

    Aug. 2004, Tanpakushitsu kakusan koso. Protein, nucleic acid, enzyme, 49 (11 Suppl), 1634 - 1640

    [Refereed]

  • A Muroyama, S Uehara, S Yatsushiro, N Echigo, R Morimoto, M Morita, M Hayashi, A Yamamoto, DS Koh, Y Moriyama

    Many metabolic factors affect the secretion of insulin from beta-cells and glucagon from alpha-cells of the islets of Langerhans to regulate blood glucose. Somatostatin from delta-cells, considered a local inhibitor of islet function, reduces insulin and glucagon secretion by activating somatostatin receptors in islet cells. Somatostatin secretion from delta-cells is increased by high glucose via glucose metabolism in a similar way to insulin secretion from beta-cells. However, it is unknown how low glucose triggers somatostatin secretion. Because L-glutamate is cosecreted with glucagon from alpha-cells under low-glucose conditions and acts as a primary intercellular messenger, we hypothesized that glutamate signaling triggers the secretion of somatostatin. In this study, we showed that delta-cells express GluR4c-flip, a newly identified splicing variant of GluR4, an (RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type ionotropic glutamate receptor of rat. After treatment with L-glutamate, AMPA, or kainate, secretion of somatostatin from isolated islets was significantly stimulated under low-glucose conditions. The glutamate-dependent somatostatin secretion was Ca2+ dependent and blocked by 6-cyano-7-nitroquinoxaline-2,3-dione. Somatostatin in turn inhibited the secretion Of L-glutamate and glucagon from a-cells. These results indicate that L-glutamate triggers somatostatin secretion from delta-cells by way of the GluR4c-flip receptor under low-glucose conditions. The released somatostatin may complete the feedback inhibition of alpha-cells. Thus, alpha- and delta-cells may communicate with each other through L-glutamate and somatostatin signaling.

    AMER DIABETES ASSOC, Jul. 2004, DIABETES, 53 (7), 1743 - 1753, English

    [Refereed]

    Scientific journal

  • M Morita, J Susuki, T Moto, C Higuchi, Y Kudo

    To study calcium imaging data of cell populations that have various response patterns in peak amplitude and frequency of calcium oscillation in response to stimulation, comprehensive characterization based on statistical analysis of each response is important. In cultures of cells that are flat and in contact with each other, it is difficult to distinguish individual cells in calcium imaging data. We have developed a novel method to determine areas corresponding to individual cells in calcium imaging data. Rat neonatal cerebral astrocytes were filled with the calcium indicator Fura2, stained with acridine orange, and illuminated with UV light. The cell nuclei were clearly visualized. In addition, the images of these nuclei were useful for analyzing concentration-dependent alteration of calcium oscillation of cultured astrocytes in response to glutamate. This novel method may be useful for studying factors affecting calcium response patterns of cultured cell populations, including culture conditions, stimulus paradigms, and synthetic compounds.

    JAPANESE PHARMACOLOGICAL SOC, Jan. 2004, JOURNAL OF PHARMACOLOGICAL SCIENCES, 94 (1), 25 - 30, English

    [Refereed]

    Scientific journal

  • Dual regulation of calcium oscillation in astrocytes by growth factors and pro-inflammatory cytokines via the mitogen-activated protein kinase cascade.

    Morita M, Higuchi C, Moto T, Kozuka N, Susuki J, Itofusa R, Yamashita J, Kudo Y

    Nov. 2003, The Journal of neuroscience : the official journal of the Society for Neuroscience, 23 (34), 10944 - 10952

    [Refereed]

  • M Morita, F Yoshiki, Y Kudo

    To elucidate the spatial and temporal relationships between phosphatidyl inositol metabolism and changes in intracellular calcium levels, we developed a simultaneous imaging system using green fluorescent protein fused with the pleckstrin homology domain, and the fluorescent calcium indicator, FuraRed. The redistribution of the fusion protein, which represents the phosphatidyl inositol metabolism process, was quantified by calculating the coefficient of variance of the fluorescence over the entire cytosolic region. excluding the nucleus. This calculation increased the reproducibility, compared to the normalized fluorescence changes in arbitrarily selected cytosolic regions used in conventional analysis. The application of this method to analyzing the response of PC12h cells to a number of pharrnacological stimuli showed that the extent of the phosphatidyl inositol metabolism was related to the calcium level, but not induced by calcium alone. (C) 2003 Elsevier Inc. All rights reserved.

    ACADEMIC PRESS INC ELSEVIER SCIENCE, Sep. 2003, BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 308 (4), 673 - 678, English

    [Refereed]

    Scientific journal

  • Y Yoshida, N Matsumoto, R Tsuchiya, M Morita, H Miyakawa, Y Kudo

    The distribution of group I metabotropic glutamate receptors in rat hippocampal cells in culture was examined by calcium imaging and immunocytochemistry. To distinguish different cell types in the culture, the effects of t-ACPD ((1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid) and of NMDA (N-methyl-D-aspartate) were examined. About 40% of the cultured cells showed either a transient increase or a sustained or oscillatory increase in the intracellular calcium concentration ([Ca2+](i)) during t-ACPD administration, while about 60% of the cells showed a sustained [Ca2+](i) increase in response to NMDA. Cells that showed an oscillatory [Ca2+](i) change during t-ACPD administration did not respond to NMDA administration, while cells that showed a sustained [Ca2+](i) increase during NMDA administration did not show any oscillatory response to t-ACPD. After Pharmacological examination using those two agonists, the cultured cells were subjected to immunocytochemistry using anti-GFAP and ant-MAP-2 antibodies to distinguish, respectively, astrocytes and neurons. All cells responding to NMDA with a sustained [Ca2+](i) increase were MAP-2-positive, whereas all cells showing either oscillatory or sustained [Ca2+](i) increase in response to t-ACPD were GFAP-positive. The present results show that, in these cultures, group I metabotropic glutamate receptors are mainly expressed on glial cells and contribute to dynamic [Ca2+](i) changes in astrocytes.

    JAPANESE PHARMACOLOGICAL SOC, Jul. 2003, JOURNAL OF PHARMACOLOGICAL SCIENCES, 92 (3), 245 - 251, English

    [Refereed]

    Scientific journal

  • R Tsuchiya, F Yoshiki, Y Kudo, M Morita

    A cell type-specific green fluorescent protein (GFP) expression system in rat cortical primary cultures has been developed for the fluorescence labeling of brain cells. Lipid-mediated transfection (lipofection) was employed, allowing the establishment of a convenient efficient system for the analysis of individual cells. To achieve cell type-specific labeling, GFP expression vectors containing the rat neuron-specific enolase (NSE) gene promoter, human glial fibril acidic protein (GFAP) gene promoter, human elongation factor (EF-1alpha) gene promoter, or human cytomegalovirus (CMV) immediate early promoter were constructed, and their specificities examined. Vectors containing the CMV or GFAP promoter resulted primarily in GFP expression in astrocytes, while those containing the EF1-alpha or NSE promoter resulted primarily in GFP expression in neurons. This labeling system was applied to the morphological analysis of living neurons and to cell type-selective calcium imaging. Confocal microscopy revealed that individual GFP-expressing neurons had processes, which were longer than 500 mum and bore spine-like protrusions. A calcium-indicating GFP variant, yellow cameleon (YC2.1), was expressed in the same system, and cell type-selective calcium imaging performed. On pharmacological stimulation, YC2.1-expressing neurons responded to depolarizing stimuli, but not to the metabotropic glutamate receptor agonist, trans-(1S, 3R)-1-amino-1,3-cyclopentanedicarboxylic acid (tACPD), while astrocytes responded only to tACPD. (C) 2002 Elsevier Science B.V. All rights reserved.

    ELSEVIER SCIENCE BV, Nov. 2002, BRAIN RESEARCH, 956 (2), 221 - 229, English

    [Refereed]

    Scientific journal

  • Glutamate receptor subunit delta 2 is highly expressed in a novel population of glial-like cells in rat pineal glands in culture

    S Yatsushiro, M Hayashi, M Morita, A Yamamoto, Y Moriyama

    The mammalian pineal gland uses L-glutamate as an intercellular chemical transmitter to regulate negatively melatonin synthesis. To receive glutamate signals, pinealocytes express at least three kinds of glutamate receptors: metabotropic receptor types 3 and 5 and an ionotropic receptor, GluR1. In this study, we examined whether or not the fourth class of ionotropic receptor, delta, which is known for its nondefinitive molecular function and its unique expression pattern in brain, is expressed in pineal gland. RT-PCR analyses with specific probes indicated the expression of mRNA of delta 2 but not that of delta 1 in pineal gland and cultured pineal cells. Western blotting analysis with polyclonal antibodies specific to the carboxyl-terminal region of the delta 2 receptor recognized a single 110-kDa polypeptide of cerebellar membranes and specifically immunostained Purkinje cells. The delta 2 antibodies recognized a 110-kDa polypeptide of pineal membranes and specifically immunostained huge glial-like cells with the occasional presence of several long, branching processes in a pineal cell culture, delta 2 is not uniformly distributed throughout the cells and is relatively abundant at the periphery of the cell bodies and long processes, where the terminals of synaptophysin-positive processes of pinealocytes, a site for glutamate secretion, are frequently present. The delta 2-positive cells constitute a very minor population among total pineal cells (similar to 0.03%). Double immunolabeling with delta 2 antibodies and antibodies against marker proteins for pineal interstitial cells clearly distinguishes delta 2-positive pineal cells and other known interstitial cells, including glial fibrillary acidic protein- or vimentin-positive glial-like cells. These results indicated that the delta 2 glutamate receptor is expressed in a novel subpopulation of pineal glial-like cells in culture and suggest the presence of a glutamate-mediated intercellular signal transduction mechanism between pinealocytes and delta 2-expressing cells, The pineal cells may provide a good experimental system for studies on the function of glutamate receptor delta 2.

    WILEY-BLACKWELL, Sep. 2000, JOURNAL OF NEUROCHEMISTRY, 75 (3), 1115 - 1122, English

    [Refereed]

    Scientific journal

  • Hirasawa, T, Nakamura, T, Mizushima, A, Morita, M, Ezawa, I, Miyakawa, H, Kudo, Y

    Jan. 2000, Br J Pharmacol, 129 (1), 21 - 28, English

    [Refereed]

    Scientific journal

  • Activation of dihydropyridine sensitive Ca2+ channels in rat hippocampal neurons in culture by parathyroid hormone

    T Hirasawa, T Nakamura, M Morita, Ezawa, I, H Miyakawa, Y Kudo

    We examined the effects of parathyroid hormone (PTH) on rat hippocampal neurons in culture to determine whether it caused a similar intracellular calcium concentration ([Ca2+](i)) increase in these cells to that seen with renal epithelial cells and found that PTH induced the effect in about 30% of the neurons. The effects appeared gradually during continuous administration of full-length PTH1-84 or its active fragment, PTH1-34, but not of an inactive fragment, PTH39-84. However, the active fragment of the PTH-related peptide (PTHrP(1-34)) had little effect on [Ca2+](i) during 60 min of administration. The PTH effect was inhibited by nifedipine, an L-type Ca2+ channel antagonist, and facilitated by S-(-)-BAY K 8644, an L-type Ca2+ channel agonist. Our findings suggest that PTH is one of the causal factors for the age-related increase in the density of voltage gated Ca2+ channels in hippocampal neurons. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.

    ELSEVIER SCI IRELAND LTD, Nov. 1998, NEUROSCIENCE LETTERS, 256 (3), 139 - 142, English

    [Refereed]

    Scientific journal

  • Microvesicle-mediated exocytosis of glutamate is a novel paracrine-like chemical transduction mechanism and inhibits melatonin secretion in rat pinealocytes

    H Yamada, A Yamamoto, S Yodozawa, S Kozaki, M Takahashi, M Morita, H Michibata, T Furuichi, K Mikoshiba, Y Moriyama

    Mammalian pinealocytes are neuroendocrine cells that synthesize and secrete melatonin, these processes being positively controlled by norepinephrine derived from innervating sympathetic neurons, Previously, we showed that pinealocytes contain a large number of microvesicles (MVs) that specifically accumulate L-glutamate through a vesicular glutamate transporter and contain proteins for exocytosis such as synaptobrevin 2 (VAMP2), These findings suggested that the MVs are counterparts of synaptic vesicles and are involved in paracrine-like chemical transduction in the pineal gland. Here, we show that pinealocytes actually secrete glutamate upon stimulation by KCl in the presence of Ca2+ at 37 degrees C, The ability of glutamate secretion disappeared when the cells were incubated at below 20 degrees C, Loss of the activity was also observed on successive stimulation, but it was recovered after 12 hr incubation. A low concentration of cadmium chloride or omega-conotoxin GVIA inhibited the secretion. Botulinum neurotoxin E cleaved synaptic vesicle-associated protein 25 (SNAP-25) and thus inhibited the secretion, The released L-glutamate stimulated pinealocytes themselves via glutamate receptor(s) and inhibited norepinephrine-stimulated melatonin secretion. These results strongly suggest that pinealocytes are glutaminergic paraneurons, and that the glutaminergic system regulates negatively the synthesis and secretion of melatonin. The MV-mediated paracrine-like chemical transduction seems to be a novel mechanism that regulates hormonal secretion by neuroendocrine cells.

    MUNKSGAARD INT PUBL LTD, Oct. 1996, JOURNAL OF PINEAL RESEARCH, 21 (3), 175 - 191, English

    [Refereed]

    Scientific journal

  • Mutational analysis of the ligand binding site of the inositol 1,4,5-trisphosphate receptor

    F Yoshikawa, M Morita, T Monkawa, T Michikawa, T Furuichi, K Mikoshiba

    To define the structural determinants for inositol 1,4,5-trisphosphate (IP3) binding of the type 1 inositol 1,4,5-trisphosphate receptor (IP(3)R1), we developed a means of expressing the N-terminal 734 amino acids of IP(3)R1 (T734), which contain the IP3 binding region, in Escherichia coli. The T734 protein expressed in E. coli exhibited a similar binding specificity and affinity for IP3 as the native IP(3)R from mouse cerebellum. Deletion mutagenesis, in which T734 was serially deleted from the N terminus up to residue 215, markedly reduced IP3 binding activity. However, when deleted a little more toward the C terminus (to residues 220, 223, and 225), the binding activity was retrieved, Further N-terminal deletions over the first 228 amino acids completely abolished it again. C-terminal deletions up to residue 579 did not affect the binding activity, whereas those up to residue 568 completely abolished it. In addition, the expressed 356-amino acid polypeptide (residues 224-579) exhibited specific binding activity. Taken together, residues 226-578 were sufficient and close enough to the minimum region for the specific IP3 binding, and thus formed an IP3 binding ''core.'' Site-directed mutagenesis was performed on 41 basic Arg and Lys residues within the N-terminal 650 amino acids of T734. We showed that single amino acid substitutions for 10 residues, which were widely distributed within the binding core and conserved among all members of the IP(3)R family, significantly reduced the binding activity. Among them, three (Arg-265, Lys-508, and Arg-511) were critical for the specific binding, and Arg-568 was implicated in the binding specificity for various inositol phosphates. We suggest that some of these 10 residues form a basic pocket that interacts with the negatively charged phosphate groups of IP3.

    AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC, Jul. 1996, JOURNAL OF BIOLOGICAL CHEMISTRY, 271 (30), 18277 - 18284, English

    [Refereed]

    Scientific journal

  • Llinas, R, Sugimori, M, Lang, E. J, Morita, M, Fukuda, M, Niinobe, M, Mikoshiba, K

    Dec. 1994, Proc Natl Acad Sci U S A, 91 (26), 12990 - 12993, English

    [Refereed]

    Scientific journal

  • Llinas, R, Sugimori, M, Chu, D, Morita, M, Blasi, J, Herreros, J, Jahn, R, Marsal, J

    May 1994, J Physiol, 477 (1), 129 - 133, English

    [Refereed]

    Scientific journal

  • Yuri Nambu, Koji Ohira, Mitsuhiro Morita, Hiroki Yasumoto, Erkin Kurganov, Seiji Miyata

    Astrocyte- and tanycyte-like neural stem cells (NSCs) were recently detected in the area postrema (AP) and central canal (CC) of the adult medulla oblongata, respectively. The present study aimed to examine dynamical behaviors of the astrocyte- and tanycyte-like NSCs of the mouse medulla oblongata to leptin. The neurosphere assay identified astrocytes in the AP and tanycytes in the CC as NSCs based on their self-renewing neurospherogenic potential. Both NSCs in neurosphere cultures were multipotent cells that generate astrocytes, oligodendrocytes, and neurons. Astrocyte-like NSCs actively proliferated and tanycyte-like NSCs were quiescent under physiologically-relevant in vivo conditions. Chronic leptin treatment promoted proliferation of astrocyte-like NSCs in the AP both in vitro and in vivo. Leptin receptors were expressed in astrocyte-like, but not tanycyte-like NSCs. Food deprivation significantly diminished proliferation of astrocyte-like NSCs. Therefore, the present study indicates that proliferation of astrocyte-like, but not tanycyte-like NSCs is regulated by nutritional conditions.

    28 May 2021, Neuroscience research, English, International magazine

    Scientific journal

MISC

  • 感知系脳室周囲器官のタニサイト様神経幹細胞

    古部 瑛莉子, 森田 光洋, 宮田 清司

    (一社)日本内分泌学会, Sep. 2015, 日本内分泌学会雑誌, 91 (2), 517 - 517, Japanese

  • Roles of astrocytes-neuron cross talking on synaptic plasticity

    Y Kudo, M Morita, H Miyakawa

    BLACKWELL PUBLISHING LTD, Dec. 2003, JOURNAL OF NEUROCHEMISTRY, 87, 15 - 15, English

    Summary international conference

Presentations

  • ATP/Adenosine release and dopamine system in cocaine-induced depressive behavior

    Morita, M, Okada, S, Kobayashi, M

    第43回日本神経科学会, 2020

    Poster presentation

  • Upregulated glutamate response and oscillation of [Ca2+]i increases of perilesional reactive astrocyte after closed-head injury

    Ueda, H, Morita, M

    第43回日本神経科学会

  • Mesenchymal stem cell promotes sphere-formation and de-differentiation of astrocytes

    Sunhwa, G, Saito, Y, Morita, M

    第43回日本神経科学会

    Poster presentation

  • 脳損傷周辺に集積するネスチン陽性活性化アストロサイトは複数の由来を持つ

    森田光洋, 岡崎夏樹, 松田ひなた, 辻恵里香

    第60回日本脳循環代謝学会, Nov. 2017, Japanese, 千里ライフサイエンス(大阪), Domestic conference

    Oral presentation

  • 脳髄間葉系幹細胞によるアストロサイトの多分可能促進

    齋藤喜仁, 森田光洋

    第60回日本脳循環代謝学会, Nov. 2017, Japanese, 千里ライフサイエンス(大阪), Domestic conference

    Oral presentation

  • Multiple origins of perilesional nestin-expressing reactive astrocytes following closed-head injury

    Morita, M, Okazaki, N, Tsuji, E

    第60回日本神経化学会, Oct. 2017, English, 仙台国際センター(宮城), Domestic conference

    Oral presentation

  • MULTIPLE ORIGINS OF PERILESIONAL NESTIN-EXPRESSING REACTIVE ASTROCYTES FOLLOWING CLOSED-HEAD INJURY

    Morita, M, Okazaki, N, Tsuji, E

    ISN-ESN Meeting, Jul. 2017, English, Le Palais des Congres de Paris(フランス), International conference

    Poster presentation

  • Multiple origins of perilesional nestin-expressing reactive astrocytes following closed-head injury

    Morita, M, Okazaki, N, Tsuji, E

    第40回日本神経科会, Jul. 2017, English, 幕張メッセ(千葉), Domestic conference

    Oral presentation

  • Localization of neural stem cells and stroke-induced generation of new neurons and glia in the medulla oblongata

    Furube, E, Hiratsuka, D, Taguchi, K, Tanaka, M, Morita, M, Miyata, S

    第40回日本神経科会, Jul. 2017, English, 幕張メッセ(千葉), Domestic conference

    Poster presentation

  • Generation of new oligodendrocytes in the medulla oblongata of mice by EAE-induced demyelination

    Hiratsuka, D, Furube, E, Morita, M, Miyata, S

    第40回日本神経科会, Jul. 2017, English, 幕張メッセ(千葉), Domestic conference

    Poster presentation

  • Bone marrow derived mesenchymal stem cells promote the multipotency of nestin-expressing reactiove astrocytes

    Saito, Y, Morita, M

    第40回日本神経科会, Jul. 2017, English, 幕張メッセ(千葉), Domestic conference

    Poster presentation

  • 骨髄間葉系幹細胞によるアストロサイトの神経幹細胞への脱分化促進

    Morita, Mitsuhiro

    神経組織培養研究会, Nov. 2016, Japanese, 横浜, Domestic conference

    Poster presentation

  • Two distinct propagation mechanisms underlying mechanically-induced calcium waves in astrocytes

    Morita, Mitsuhiro, Fujii Yuki

    FENS, Jul. 2016, English, Copenhagen, Denmark, International conference

    Poster presentation

  • Proximal propagation of mechanically-induced calcium wave between astrocytes is mediated by gap junction, while distal propagation is mediated by diffusion of ATP released by volume-regulated anion channel

    Morita, Mitsuhiro, Fujii Yuki

    日本神経科学会, Jul. 2016, Japanese, 横浜, Domestic conference

    Poster presentation

  • Perilesional nestin-expressing reactive astrocyte is required for cortical recovery after focal brain injury and ablated after wound healing.

    Morita, M, Watanabe, A, Tsuji, E, Maekawa, S

    Euroglia; XII European Meeting on Glial Cells in Health and Disease, 2015, English, International conference

    Poster presentation

  • Neural stem cells and progenitor cells in the sensory circumventricular organs of adult mouse

    Furube, E, Morita, M, Miyata, S

    The 38th Annual Meeting of the Japan Neuroscience Society, 2015, Japanese, Domestic conference

    Poster presentation

  • Broad impairment of the flow of cerebrospinal fluid, glymphatic system after focal closed head injury

    Sakakibara, R, Morita, M

    The 38th Annual Meeting of the Japan Neuroscience Society, 2015, Japanese, Domestic conference

    Poster presentation

  • Ablation of nestin-expressing reactive astrocytes after cortical tissue regeneration in a closed-head injury model

    Morita, M, Tsuji, E, Watanabe, A

    The 38th Annual Meeting of the Japan Neuroscience Society, 2015, Japanese, Domestic conference

    Poster presentation

  • Two adenosine release mechanisms in rat hippocampus

    Fujii,Y, Yamashiro,K, MORITA MITSUHIRO

    Neuroscience 2014(日本神経科学会), 2014, English, 横浜, Domestic conference

    Poster presentation

  • STAT3 signaling in perilesional nestin-expressing reactive astrocyte is required for cortical recovery after closed-head injury.

    Watanabe,A, MORITA MITSUHIRO

    Neuroscience 2014(日本神経科学会), 2014, English, 横浜, Domestic conference

    Poster presentation

  • STAT3 Signaling in Perilesional Nestin-Expressing Reactive Astrocyte is Required for Cortical Recovery after Closed-Head Injury

    MORITA MITSUHIRO, Watanabe,A

    Society for Neurosci,, 2014, English, Washington DC, International conference

    Poster presentation

  • Regulatory effect of NAP-22 on the activity of calcineurin.

    小林 優美, 熊ノ郷 晴子, MORITA MITSUHIRO, 中村 俊, MAEKAWA SHOHEI

    Neuro 2013 (第36回日本神経科学大会), Jun. 2013, English, 国立京都国際会館, Domestic conference

    Oral presentation

  • Interaction of NAP-22 with brain glutamic acid decarboxylase(GAD)

    MAEKAWA SHOHEI, 小林 優美, 小田垣 真一, 牧野 碧, 熊ノ郷 晴子, 中村 俊, MORITA MITSUHIRO, 林 文夫

    Neuro 2013 (第36回日本神経科学大会), Jun. 2013, English, 国立京都国際会館, Domestic conference

    Oral presentation

  • 新規脳傷害モデル「光傷害」における脳組織再生とグリア細胞の活性化

    MORITA MITSUHIRO

    第25回日本脳循環代謝学会総会, 2013, Japanese, 札幌, Domestic conference

    Oral presentation

  • he evoked increase of extracellular adenosine in rat hippocampus CA1 region depends on L-type Ca2+ channel.

    Morita Mitsuhiro, Yamashiro, K

    Neuro2013, 2013, English, Kyoto, Domestic conference

    Oral presentation

  • Monitoring adenosine level in rat hippocampal slice by adenosine sensor cell

    Morita Mitsuhiro, Yamashiro, K

    日本神経科学科会, 2012, English, 名古屋, International conference

    Oral presentation

  • Monitoring adenosine level in rat hippocampal slice by adenosine sensor cell

    Morita Mitsuhiro, Yamashiro, K

    Society for Neuroscience, 2012, English, New Orleans, International conference

    Oral presentation

  • Adenosine release in rat hippocampal slice measured by a novel adenosine sensor cell

    Morita Mitsuhiro, Yamashiro, K

    The 11th Biennial Meeting of the Asian Pacific Society for Neurochemistry / The 55th Annual Meeting for the Japanese Society for Neurochemistry, 2012, English, 神戸, International conference

    Oral presentation

  • Perilesional nestin-expressing reactive astrocytes and cortical tissue recovery in a novel closed-head injury model, photo injury

    MORITA Mitsuhiro

    10th European Meeting on Glial Cells in Health and Disease, Sep. 2011, English, Prague, Czech Republic, International conference

    Poster presentation

  • Perilesional nestin-expressing reactive astrocytes and cortical tissue recovery in a novel closed-head injury model, photo injury

    MORITA Mitsuhiro

    Gordon Research Conference, Mar. 2011, English, Los Angels,USA, International conference

    Poster presentation

  • Perilesional nestin-expressing reactive astrocytes and the cortical tissue recovery of a novel brain injury model (photo injury)

    MORITA Mitsuhiro

    内藤カンファレンスGlial Biology, Oct. 2010, English, 内藤財団, 逗子, Domestic conference

    Poster presentation

  • Perilesional nestin-expressing reactive astrocytes in a novel brain injury model (photo injury)

    MORITA Mitsuhiro

    Neuro2010, Sep. 2010, English, 日本神経科学会, 神戸, Domestic conference

    Poster presentation

Research Projects

  • 森田 光洋

    学術研究助成基金助成金/基盤研究(C), Apr. 2018 - Mar. 2021, Principal investigator

    Competitive research funding

  • 森田 光洋

    学術研究助成基金助成金/基盤研究(C), Apr. 2017 - Mar. 2021, Principal investigator

    Competitive research funding

  • 森田 光洋

    学術研究助成基金助成金/基盤研究(C), Apr. 2014 - Mar. 2017, Principal investigator

    Competitive research funding

  • A-STEP「脳傷害に伴う脳内循環Glymphatic systemの不全を画像化する技術の開発」

    森田 光洋

    科学技術振興機構, 研究成果最適展開支援プログラム フィージビリティスタディステージ 探索タイプ, 2015, Principal investigator

    Competitive research funding

  • A-STEP「脂肪酸放射標識化合物を用いた脳組織再生の画像診断技術の確立」

    森田 光洋

    科学技術振興機構, 研究成果最適展開支援プログラム シーズ顕在化タイプ, 2015, Principal investigator

    Competitive research funding

  • A-STEP「脳傷害に伴う脳内循環Glymphatic systemの不全を画像化する技術の開発」

    森田 光洋

    研究成果最適展開支援プログラム フィージビリティスタディステージ 探索タイプ, 2014, Principal investigator

    Competitive research funding

  • A-STEP「脂肪酸放射標識化合物を用いた脳組織再生の画像診断技術の確立」

    森田 光洋

    研究成果最適展開支援プログラム シーズ顕在化タイプ, 2014, Principal investigator

    Competitive research funding

  • A-STEP「神経保護・再生機能を持つ活性化アストロサイトを検出するための放射性イメージング剤の開発」

    森田 光洋

    研究成果最適展開支援プログラム フィージビリティスタディステージ 探索タイプ, 2013, Principal investigator

    Competitive research funding

  • A-STEP「神経保護・再生機能を持つ活性化アストロサイトを検出するための放射性イメージング剤の開発」

    森田 光洋

    研究成果最適展開支援プログラム フィージビリティスタディステージ 探索タイプ, 2012, Principal investigator

    Competitive research funding

  • 森田 光洋

    科学研究費補助金/新学術領域研究, 2011, Principal investigator

    Competitive research funding

  • 森田 光洋

    科学研究費補助金/基盤研究(B), 2011, Principal investigator

    Competitive research funding

  • 文部科学省, 科学研究費補助金(特定領域研究), 2003 - 2007

    1)高頻度反復シナプス入力によって海馬アストロサイトに誘起されるコンダクタンス上昇の原因を検討した結果、錐体細胞に誘起される新規なプラトー状電位の存在を見出した。この電位はシナプス外NMDA受容体の活性化に起因しており、アストロサイトーニューロン間の相互作用を担うものであることが期待される(論文投稿中)。さらに、この電位の発生に伴い、錐体細胞にNMDA受容体チャネルからの流入に起因するCa上昇が誘起されることを見出した。多くの神経疾患の最終過程としてNMDA受容体の過活性化による細胞障害が仮説として検討されている。アストロサイトからのグルタミン酸放出と神経障害を結ぶ過程として興味深い。 2)成熟動物から作成した海馬スライス内のアストロサイトおよびニューロンが同期的自発Ca変動を示すことをbolus loading法によるCaイメージング法を用いて確認した。また、電気生理的手法により、ニューロンが自発的にプラトー状の電位を発生していることを

    Competitive research funding

  • 文部科学省, 科学研究費補助金(若手研究(B)), 2002 - 2003

    オクトパミンは無脊椎動物にみられる神経伝達物質であり、脊椎動物では合成されず受容体も存在しない。ショウジョウバエのオクトパミン受容体はGタンパク質共役型であり、細胞内カルシウム上昇とcAMP産生を引き起こすことが知られている。オクトパミン受容体遺伝子を脊椎動物由来の細胞に導入した場合、遺伝子発現した細胞選択的に細胞応答が引き起こされると予想される。この点に注目し、複雑な神経回路網において特定の細胞が示すカルシウム上昇などがシステム全体に果たす役割を解明する手段の開発を試みた。具体的にはオクトパミン受容体が脊椎動物細胞において引き起こす細胞応答の解析と、細胞種特異的プロモーターを用いた標的細胞におけるオクトパミン受容体の発現と、これにより引き起こされる神経活動の解析を行った。哺乳動物由来であるPC12h細胞、初代培養神経細胞およびアストロサイトにオクトパミン受容体を発現させた場合、PC12h細胞とアストロサイト

    Competitive research funding

  • 文部科学省, 科学研究費補助金(基盤研究(B)), 1999 - 2002

    本研究の目的は海馬の神経ネットワーク振動の成因を解明することであった。この研究を始めるにいたった動機は、能動性樹状突起と抑制性ニューロンの回路網との相互作用が脳・神経系における情報処理に重要であるという仮説であった。この目的のために、電位感受性色素を用いた光学的手段によって海馬スライス標本の神経活動を観測し、電気生理学的手段によって観測した神経活動とあわせて解析した。最終目的である海馬の神経ネットワーク振動の成因の解明にはいたらなかったが、能動性樹状突起と抑制性ニューロンの回路網との相互作用に関しては着実な成果を挙げることができた。その第一は、海馬CA1錐体細胞樹状突起の全長にわたってシナプス応答が非線型的加算を行い、非線型性はGABA作動性入力によってもたらされていることを明らかにしたものである。.この研究には電気生理学的手法(Hippocampus,2001)と電位感受性蛍光色素を用いた高速光学測定(Neuroscience2002)とを用い

    Competitive research funding

  • 文部科学省, 科学研究費補助金(特定領域研究(B)), 1998 - 2002

    初代培養されたラットのアストロサイトに神経伝達物質を適用した場合のカルシウム応答には大きなばらつきがある。その原因を明らかにする目的で、培養アストロサイトのカルシウム応答に影響を与える因子を検討した。さらに、脳スライス標本を用いて、アストロサイトのカルシウム応答の脳機能における意義を検討した。EGFやBasic FGFのような成長因子はグルタミン酸やATPなどの刺激薬を適用した時や、細胞内IP3受容体を直接活性化させる薬物であるチメロサールを適用した場合のカルシウムオシレーションの発現に必須であることが判明した。これらの成長因子による処置は細胞内カルシウム貯蔵量を増大させ、アストロサイトの形状を繊維状に変化させた。これらの反応は全て炎症性サイトカイン(Interleukin-1β:IL1-βやTumor necrosis factor-α:TNF-α)、Lipopolysaccharide、やMAPK(Mitogen activated cytokinase)の阻害薬、U0126によって抑制された。この事実はカルシウムオシレーション発現にはMAPKが関与し

    Competitive research funding

  • 文部科学省, 科学研究費補助金(奨励研究(A)), 1998 - 1999

    本研究は神経系における特定の細胞集団を蛍光標識し、それらの細胞集団が示す生理反応をそれ以外の細胞から差別化して測定する手法の開発を目的とした。具体的にはGFP(Green Fluorescence Protein)とその改変体を利用して遺伝子工学的に細胞内カルシウム、膜電位などの測定を行う技術を開発する(測定技術の開発)とともに、神経組織由来の初代培養細胞にこれらの遺伝子産物を細胞種特異的なプロモーター(遺伝子の転写調節領域)を利用して発現させて標識し、標識された細胞を差別化して測定を行う(標識技術の開発)ことを目指した。測定技術の開発としては、GFPと既存のカルシウム蛍光色素との間で見られる相互作用に着目して試験管内の検討を行った。その結果、GFPとfura-redもしくはBFP、CFP(blueまたはcyanの蛍光を発するGFPの改変体)とfura-redを共存させた状態においてカルシウム依存的なGFP由来の蛍光の変化が見られた。これはfura-redのカルシウム依存的な吸収スペクトルの変化がGFPの蛍光

    Competitive research funding

  • 文部科学省, 科学研究費補助金(基盤研究(A)), 1996 - 1998

    蛍光Ca2+指示薬による細胞内Ca2+濃度の画像による解析法が利用できるようになって、生細胞内の特定分子のダイナミックな活動様式を可視化を試みる研究に拍車がかかった。というのも、この方法を使えば特定の機能分子の細胞内で、部位特性や活性化時間など新しい情報を提供してくれるからである。このプロジェクトにおいて我々は細胞機能のダイナミックな調節に最も重要な酵素である二種のリン酸化酵素の活性を直接可視化する特異的指示薬を作り出すことおよび微弱な蛍光の変化を確実に解析するシステムを構築することにを目的とした。最初にCa+/カルモデュリン依存性キナ-ゼ(CaMKII)活性の可視化のためにCaMKIIの特異的基質ペプチド、Syntide2のN-末端に蛍光指示薬、Acrylodanを結合させた試薬、AS2を創製し、まず、試験官内でこの試薬がCa2+で活性化されたカルモデュリンとそれによって活性化されるCaMKIIの有効な指示薬になることを確かめた。一方、cAMP依存性キナ-ゼ(PKA)の活性を可

    Competitive research funding