Ishibashi T

References (7)

Title : Evaluation of radiolabeled acetylcholine synthesis and release in rat striatum - Muramatsu_2021_J.Neurochem__
Author(s) : Muramatsu I , Uwada J , Chihara K , Sada K , Wang MH , Yazawa T , Taniguchi T , Ishibashi T , Masuoka T
Ref : Journal of Neurochemistry , : , 2021
Abstract : Cholinergic transmission underlies higher brain functions such as cognition and movement. To elucidate the process whereby acetylcholine (ACh) release is maintained and regulated in the central nervous system, uptake of [3H]choline and subsequent synthesis and release of [3H]ACh were investigated in rat striatal segments. Incubation with [3H]choline elicited efficient uptake via high-affinity choline transporter-1, resulting in accumulation of [3H]choline and [3H]ACh. However, following inhibition of ACh esterase (AChE), incubation with [3H]choline led predominantly to the accumulation of [3H]ACh. Electrical stimulation and KCl depolarization selectively released [3H]ACh but not [3H]choline. [3H]ACh release gradually declined upon repetitive stimulation, whereas the release was reproducible under inhibition of AChE. [3H]ACh release was abolished after treatment with vesamicol, an inhibitor of vesicular ACh transporter. These results suggest that releasable ACh is continually replenished from the cytosol to releasable pools of cholinergic vesicles to maintain cholinergic transmission. [3H]ACh release evoked by electrical stimulation was abolished by tetrodotoxin, but that induced by KCl was largely resistant. ACh release was Ca2+ dependent and exhibited slightly different sensitivities to N- and P-type Ca2+ channel toxins (omega(-) conotoxin GVIA and omega-agatoxin IVA, respectively) between both stimuli. [3H]ACh release was negatively regulated by M2 muscarinic and D2 dopaminergic receptors. The present results suggest that inhibition of AChE within cholinergic neurons and of presynaptic negative regulation of ACh release contributes to maintenance and facilitation of cholinergic transmission, providing a potentially useful clue for the development of therapies for cholinergic dysfunction-associated disorders, in addition to inhibition of synaptic cleft AChE.
ESTHER : Muramatsu_2021_J.Neurochem__
PubMedSearch : Muramatsu_2021_J.Neurochem__
PubMedID: 34878648

Title : Augmentation of Endogenous Acetylcholine Uptake and Cholinergic Facilitation of Hippocampal Long-Term Potentiation by Acetylcholinesterase Inhibition - Masuoka_2019_Neurosci_404_39
Author(s) : Masuoka T , Uwada J , Kudo M , Yoshiki H , Yamashita Y , Taniguchi T , Nishio M , Ishibashi T , Muramatsu I
Ref : Neuroscience , 404 :39 , 2019
Abstract : Hippocampal cholinergic activity enhances long-term potentiation (LTP) of synaptic transmission in intrahippocampal circuits and regulates cognitive function. We recently demonstrated intracellular distribution of functional M1-muscarinic acetylcholine receptors (mAChRs) and neuronal uptake of acetylcholine (ACh) in the central nervous system. Here we examined whether endogenous ACh acts on intracellular M1-mAChRs following its uptake and causes cholinergic facilitation of hippocampal LTP. ACh esterase (AChE) activities and [(3)H]ACh uptake was measured in rat hippocampal segments. LTP of evoked field excitatory postsynaptic potentials at CA1 synapses was induced by high frequency stimulation in hippocampal slices. Pretreatment with diisopropylfluorophosphate (DFP) irreversibly inhibited AChE, augmented ACh uptake, and significantly enhanced the LTP. This cholinergic facilitation was inhibited by pirenzepine, a membrane-permeable M1 antagonist, while only the early stage of cholinergic facilitation was inhibited by a membrane-impermeable M1 antagonist, muscarinic toxin 7. Tetraethylammonium (TEA) inhibited ACh uptake in hippocampal segments and selectively suppressed late stage cholinergic facilitation without changing the early stage. In contrast, LTP in DFP-untreated slices was not affected by the muscarinic antagonists and TEA. Carbachol (CCh; an AChE-resistant muscarinic agonist) competed with ACh for its uptake and produced cholinergic facilitation of LTP in DFP-untreated slices. The late stage of CCh-induced facilitation was also selectively inhibited by TEA. Our results suggest that when AChE is inactivated by inhibitors, LTP in hippocampal slices is significantly enhanced by endogenous ACh and that cholinergic facilitation is caused by direct activation of cell-surface M1-mAChRs and subsequent activation of intracellular M1-mAChRs after ACh uptake.
ESTHER : Masuoka_2019_Neurosci_404_39
PubMedSearch : Masuoka_2019_Neurosci_404_39
PubMedID: 30708046

Title : Population Pharmacokinetic and Exposure-Response Analyses of Baloxavir Marboxil in Adults and Adolescents Including Patients With Influenza - Koshimichi_2019_J.Pharm.Sci_108_1896
Author(s) : Koshimichi H , Tsuda Y , Ishibashi T , Wajima T
Ref : J Pharm Sci , 108 :1896 , 2019
Abstract : Baloxavir marboxil, a prodrug that is metabolized to baloxavir acid, suppresses viral replication by inhibiting cap-dependent endonuclease. Our aim is to characterize its pharmacokinetics and exposure-response relationships. Population pharmacokinetic analysis of the baloxavir acid was performed using 8310 plasma concentration data points from 1109 subjects. Exposure-response analyses were performed regarding the time to alleviation of symptoms and the reduction in the influenza virus titer. A 2-compartment model with first-order absorption and lag time well described the plasma concentration data for baloxavir acid, and body weight and race were found to be the most important factors influencing the clearance and distribution volume. A dose regimen based on the body weight (40 mg for patients weighing <80 kg and 80 mg for patients weighing <=80 kg) could provide sufficient exposures for expecting efficacy irrespective of body weight or race; however, the exposures were dependent on the body weight and race. Exposure-response analyses suggested that the reduction in the influenza virus titer was greater in any exposure-based groups in baloxavir marboxil treatment than in the oseltamivir phosphate treatment and placebo groups. In conclusion, the population pharmacokinetic model and exposure-response relationships would be useful for understanding the pharmacokinetic and pharmacodynamic characteristics of baloxavir acid.
ESTHER : Koshimichi_2019_J.Pharm.Sci_108_1896
PubMedSearch : Koshimichi_2019_J.Pharm.Sci_108_1896
PubMedID: 30557562

Title : Ab initio model study on acetylcholinesterase catalysis: potential energy surfaces of the proton transfer reactions - Tachikawa_2005_J.Photochem.Photobiol.B_79_11
Author(s) : Tachikawa H , Igarashi M , Nishihira J , Ishibashi T
Ref : J Photochem Photobiol B , 79 :11 , 2005
Abstract : Ab initio molecular orbital (MO) and hybrid density functional theory (DFT) calculations have been applied to the initial step of the acylation reaction catalyzed by acetylcholinesterase (AChE), which is the nucleophiric addition of Ser200 in catalytic triads to a neurotransmitter acetylcholine (ACh). We focus our attention mainly on the effects of oxyanion hole and Glu327 on the potential energy surfaces (PESs) for the proton transfer reactions in the catalytic triad Ser200-His440-Glu327. The activation barrier for the addition reaction of Ser200 to ACh was calculated to be 23.4 kcal/mol at the B3LYP/6-31G(d)//HF/3-21G(d) level of theory. The barrier height under the existence of oxyanion hole, namely, Ser200-His440-Glu327-ACh-(oxyanion hole) system, decreased significantly to 14.2 kcal/mol, which is in reasonable agreement with recent experimental value (12.0 kcal/mol). Removal of Glu327 from the catalytic triad caused destabilization of both energy of transition state for the reaction and tetrahedral intermediate (product). PESs calculated for the proton transfer reactions showed that the first proton transfer process is the most important in the stabilization of tetrahedral intermediate complex. The mechanism of addition reaction of ACh was discussed on the basis of theoretical results.
ESTHER : Tachikawa_2005_J.Photochem.Photobiol.B_79_11
PubMedSearch : Tachikawa_2005_J.Photochem.Photobiol.B_79_11
PubMedID: 15792875

Title : Complete sequencing and characterization of 21,243 full-length human cDNAs - Ota_2004_Nat.Genet_36_40
Author(s) : Ota T , Suzuki Y , Nishikawa T , Otsuki T , Sugiyama T , Irie R , Wakamatsu A , Hayashi K , Sato H , Nagai K , Kimura K , Makita H , Sekine M , Obayashi M , Nishi T , Shibahara T , Tanaka T , Ishii S , Yamamoto J , Saito K , Kawai Y , Isono Y , Nakamura Y , Nagahari K , Murakami K , Yasuda T , Iwayanagi T , Wagatsuma M , Shiratori A , Sudo H , Hosoiri T , Kaku Y , Kodaira H , Kondo H , Sugawara M , Takahashi M , Kanda K , Yokoi T , Furuya T , Kikkawa E , Omura Y , Abe K , Kamihara K , Katsuta N , Sato K , Tanikawa M , Yamazaki M , Ninomiya K , Ishibashi T , Yamashita H , Murakawa K , Fujimori K , Tanai H , Kimata M , Watanabe M , Hiraoka S , Chiba Y , Ishida S , Ono Y , Takiguchi S , Watanabe S , Yosida M , Hotuta T , Kusano J , Kanehori K , Takahashi-Fujii A , Hara H , Tanase TO , Nomura Y , Togiya S , Komai F , Hara R , Takeuchi K , Arita M , Imose N , Musashino K , Yuuki H , Oshima A , Sasaki N , Aotsuka S , Yoshikawa Y , Matsunawa H , Ichihara T , Shiohata N , Sano S , Moriya S , Momiyama H , Satoh N , Takami S , Terashima Y , Suzuki O , Nakagawa S , Senoh A , Mizoguchi H , Goto Y , Shimizu F , Wakebe H , Hishigaki H , Watanabe T , Sugiyama A , Takemoto M , Kawakami B , Watanabe K , Kumagai A , Itakura S , Fukuzumi Y , Fujimori Y , Komiyama M , Tashiro H , Tanigami A , Fujiwara T , Ono T , Yamada K , Fujii Y , Ozaki K , Hirao M , Ohmori Y , Kawabata A , Hikiji T , Kobatake N , Inagaki H , Ikema Y , Okamoto S , Okitani R , Kawakami T , Noguchi S , Itoh T , Shigeta K , Senba T , Matsumura K , Nakajima Y , Mizuno T , Morinaga M , Sasaki M , Togashi T , Oyama M , Hata H , Komatsu T , Mizushima-Sugano J , Satoh T , Shirai Y , Takahashi Y , Nakagawa K , Okumura K , Nagase T , Nomura N , Kikuchi H , Masuho Y , Yamashita R , Nakai K , Yada T , Ohara O , Isogai T , Sugano S
Ref : Nat Genet , 36 :40 , 2004
Abstract : As a base for human transcriptome and functional genomics, we created the "full-length long Japan" (FLJ) collection of sequenced human cDNAs. We determined the entire sequence of 21,243 selected clones and found that 14,490 cDNAs (10,897 clusters) were unique to the FLJ collection. About half of them (5,416) seemed to be protein-coding. Of those, 1,999 clusters had not been predicted by computational methods. The distribution of GC content of nonpredicted cDNAs had a peak at approximately 58% compared with a peak at approximately 42%for predicted cDNAs. Thus, there seems to be a slight bias against GC-rich transcripts in current gene prediction procedures. The rest of the cDNAs unique to the FLJ collection (5,481) contained no obvious open reading frames (ORFs) and thus are candidate noncoding RNAs. About one-fourth of them (1,378) showed a clear pattern of splicing. The distribution of GC content of noncoding cDNAs was narrow and had a peak at approximately 42%, relatively low compared with that of protein-coding cDNAs.
ESTHER : Ota_2004_Nat.Genet_36_40
PubMedSearch : Ota_2004_Nat.Genet_36_40
PubMedID: 14702039
Gene_locus related to this paper: human-ABHD1 , human-ABHD4 , human-ABHD12 , human-ABHD16A , human-ACOT1 , human-LDAH , human-ABHD18 , human-CES1 , human-CES4A , human-CES5A , human-CPVL , human-DAGLB , human-EPHX2 , human-KANSL3 , human-LIPA , human-LPL , human-MEST , human-NDRG1 , human-NLGN1 , human-NLGN4X , human-PRCP , human-PRSS16 , human-SERAC1 , human-TMEM53

Title : Megakaryocytic Maturation is Regulated by Maintaining a Balance Against Cytokine Induced-cell Proliferation: Steel Factor Retards Thrombopoietin-induced Megakaryocytic Differentiation While Synergistically Stimulating Mitogenesis\; Hematopoiesis - Miyazawa_2000_Hematol_5_233
Author(s) : Miyazawa K , Nishimaki J , Katagiri T , Yaguchi M , Iwase O , Gotoh A , Tauchi T , Kawanishi Y , Toyama K , Ohyashiki K , Ishibashi T , Broxmeyer HE
Ref : Hematol , 5 :233 , 2000
Abstract : Using a factor-dependent cell line MO7ER, which contains a stably transduced human erythropoietin (EPO) receptor gene in human megakaryoblastic cell line MO7e and which resulted in concomitant expression of EPO receptor, c-Mpl and c-Kit, we investigated the biological effects of these cytokines in terms of cell growth and differentiation. Thrombopoietin (TPO), EPO and Steel factor (SLF) all stimulated MO7ER cell proliferation in a dose-dependent manner. Combined stimulation of cells with SLF plus either TPO or EPO resulted in striking synergistic enhancement of MO7ER cell growth as compared with each cytokine alone, whereas combination of TPO plus EPO showed only an additive effect on cell proliferation. With regards to cell differentiation, either TPO or EPO treatment induced enhancement of platelet glycoprotein (GP) IIb/IIIa and GPIb expression. SLF induced GPIIb/IIIa and GPIb expression, but the effect was much weaker than that of EPO or TPO. However, addition of SLF to either TPO- or EPO- containing cultures (which induced potent mitogenesis in MO7ER cells) resulted in suppression of these megakaryocyte specific antigens. Addition of low-dose cytosine arabinoside (Ara-C)(1 to 10 ng/ml) enhanced TPO- or EPO- induced megakaryocytic differentiation in MO7ER cells while mildly suppressing cell growth. Treatment the cells with low-dose Ara-C plus TPO plus SLF overrode the proliferative enhancing effects of SLF and induced GPIIb/IIIa and GPIb expression as efficient as TPO alone. Retardation of TPO-induced megakaryocytic maturation was also observed in normal murine bone marrow cells by combined stimulation with TPO and SLF as assessed by the numbers of acetylcholinesterase staining-positive cells and megakaryocyte nuclear polyploidy. These results suggest that megakaryocytic maturation is, at least in part, regulated by countering cytokine-induced cell proliferation.
ESTHER : Miyazawa_2000_Hematol_5_233
PubMedSearch : Miyazawa_2000_Hematol_5_233
PubMedID: 11399618

Title : Purification and characterization of lipase from Rhizopus chinensis cells - Yasuda_1999_J.Biosci.Bioeng_88_571
Author(s) : Yasuda M , Ogino H , Kiguchi T , Kotani T , Takakura S , Ishibashi T , Nakashima T , Fukuda H , Ishikawa H
Ref : J Biosci Bioeng , 88 :571 , 1999
Abstract : Lipase from Rhizopus chinensis cells was purified and characterized. The molecular mass of purified lipase was 28.4 kDa and the optimal temperature and pH for its activity were 37 degrees C and 5.5, respectively. Purified lipase exhibited high hydrolytic activity against fatty acid methyl esters such as methyl caprylate, methyl laurate, and methyl palmitate. Freeze-dried lipase catalyzed the transesterification between olive oil and methyl laurate in n-hexane.
ESTHER : Yasuda_1999_J.Biosci.Bioeng_88_571
PubMedSearch : Yasuda_1999_J.Biosci.Bioeng_88_571
PubMedID: 16232664