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Hiroshi Ueda

Publications and source records attributed to Hiroshi Ueda.

At least 73 records · Page 4Linked to original sources
PubMed2004

Cell death mode switch from necrosis to apoptosis in brain.

In brain ischemia, cell destructive necrosis occurs in the core, which in turn links to cell death expansion in the vicinity. Apoptosis, on the other hand, occurs in the surroundings of the core, called the penumbra, several days later. As cells showing apoptosis disappear by microglial phagocytosis in the brain, cell death induced by ischemic stress should eventually be terminated. Thus, the authors propose the hypothesis that the cell death mode switch in the event of brain ischemia is an in vivo self-protective mechanism. The authors attempt to overview the current understanding of the molecular mechanisms of necrosis and apoptosis in relation to the ATP hypothesis, and also introduce novel mechanisms for an in vitro cell death mode switch.

Animals↗
PubMed2004

A hydroxyl group of flavonoids affects oral anti-inflammatory activity and inhibition of systemic tumor necrosis factor-alpha production.

We previously reported that oral administration of luteolin can inhibit serum tumor necrosis factor (TNF)-alpha production and several inflammatory and allergic models. We investigated here the effect of various flavonoids which resemble luteolin in structure. Lipopolysaccharide (LPS)-induced TNF-alpha production from macrophages was inhibited by treatment with flavone (luteolin, apigenin, and chrysin), flavonol (quercetin and myricetin), flavanonol (taxifolin), and anthocyanidin (cyanidin chloride) in vitro. Most of these, however, did not affect mice when administered orally. Serum TNF-alpha production was inhibited only by luteolin or apigenin, and only luteolin or quercetin inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced ear edema. These results suggest that the structure of luteolin: 3',4',5,7-tetrahydroxyflavone, is most suitable for the oral anti-inflammatory activity and that existence or disappearance of a hydroxy group may cause a loss of efficiency.

Administration, Oral↗
PubMed2004

Anti-opioid systems in morphine tolerance and addiction--locus-specific involvement of nociceptin and the NMDA receptor.

Mechanisms for opioid tolerance and addiction are divided into two types of plasticity--cellular level and those occurring through multiple neuronal networks. Receptor desensitization through phosphorylation and endocytosis are currently well discussed using cell lines expressing opioid receptors in relation to acute tolerance mechanisms, while altered gene expression is mainly discussed in relation to the model mechanisms of chronic tolerance and dependence. However, little is known of mechanisms operating through plasticity of neuronal networks. In our approach, we began with the assumption that some non-opioid neurons with anti-opioid activity may cause neuronal plasticity, showing opioid adaptation and dependence. In mice lacking nociceptin/orphanin FQ receptor (NOP), or the NMDA receptor epsilon1 subunit, both of which mediate anti-opioid activities, analgesic tolerance and dependence following chronic morphine treatments were markedly attenuated. Chronic morphine-treatments increased NOP gene or epsilon1 subunit protein expression in the spinal cord or specific brain loci, respectively. Furthermore the rescue of the epsilon1 subunit gene in the specific brain locus of knockout mice recovers the tolerance and dependence. All these results suggest that the enhanced anti-opioid system may contribute to the development of morphine tolerance and dependence, and their contribution could be brain locus specific.

Animals↗
PubMed2003

Enhanced expression of neuronal nitric oxide synthase in islets of exercise-trained rats.

It is well known that glucose-stimulated insulin secretion (GSIS) decreases after exercise training. In the present study, we investigated the effects of exercise training (9 weeks of running) on the activity of glucokinase (GK), the production of nitric oxide (NO), and the protein expressions of both glucose transporter-2 (GLUT-2) and NO synthase (NOS) in rat pancreatic islets. Exercise training significantly reduced GSIS, with decreases in GK activity and GLUT-2 protein expression. The NO releases and cGMP contents were higher in the islets of trained rats than in those of control rats. Exercise training enhanced cNOS activity, the protein expression of both neuronal nitric oxide synthase (nNOS) and calmodulin, and NADPH-cytochrome c reductase activity in the homogenates of islets. Thus, exercise training-induced reduction of GSIS would result from, at least in part, decreases in both glucose entry and the first step in glycolytic utilization of glucose. Moreover, exercise training could enhance the protein expression of nNOS, which in turn enhances two catalytic activities of nNOS, an NO production and a cytochrome c reductase activity.

Animals↗
PubMed2003

Intracerebroventricular injection of muscimol, baclofen or nipecotic acid stimulates food intake in layer-type, but not meat-type, chicks.

This study was designed to compare the effects of muscimol (GABA(A) agonist), baclofen (GABA(B) agonist) and nipecotic acid (GABA uptake inhibitor) on food intake in two chicken strains (meat-type and layer-type chicks). The intracerebroventricular (ICV) injection of all GABA agents induced hyperphagia in layer-type chicks. However, in broiler chicks, there were similar tendencies with muscimol and nipecotic acid but not significantly different. Conversely, ICV injection of baclofen depressed feeding of broiler chicks. These results suggest that there are some differences in central GABAergic systems between these strains of chicks, but GABAergic systems have an important role in the regulation of food intake in neonatal chicks.

Animals↗
PubMed2003

New approaches to study the development of morphine tolerance and dependence.

Morphine is now believed not to cause tolerance and dependence when it is appropriately used in clinic. However, in terminal cancer pain, patients' analgesic tolerance to morphine is developed due to the use of high doses of morphine for complete blockade of pain. At higher doses, morphine has more opportunity to show serious side effects, which worsens quality of life (QOL), and leads to the use of potent analgesic adjuvants to reduce the morphine dosage. Here we attempt to summarize recent studies of the molecular basis of morphine tolerance and dependence, and to discuss whether these mechanisms could provide new molecular targets as analgesic adjuvants. They include protein kinase C inhibitor, opioid agonist with low RAVE value, and antagonists of antiopioid receptors (GluRepsilon1 or nociceptin/OFQ receptor). In addition, we demonstrate new approaches to find further candidates of such molecular targets. These approaches include the visualization of neuronal networks in the downstream of opioid neurons by use of the WGA transgene technique and the single cell dissection technique to get new genes involved in plasticity during morphine tolerance and dependence.

Analgesics, Opioid↗
PubMed2003

Switching of bradykinin-mediated nociception following partial sciatic nerve injury in mice.

Bradykinin (BK) is well known as a potent mediator of pain and hyperalgesia. Using a highly sensitive nociception test, we found that intraplantar (i.pl.) injection of BK produced nociceptive hyper-responses in partial sciatic nerve-injured mice, compared with the control sham-operated animals. By use of selective agonists and antagonists, we revealed that BK nociception in sham-operated mice was mediated through B2 receptor, whereas that in injured mice was mediated through B1 receptor. When we examined the activation of extracellular signal-regulated protein kinase (ERK) in dorsal root ganglion (DRG) neurons upon i.pl. injection of BK, phosphorylated ERK was mainly observed in unmyelinated neurons in sham-operated mice, and in case of nerve-injured mice, ERK was mainly activated in myelinated neurons and satellite cells. The B1 receptor agonist, [Lys-des-Arg(9)]-BK also produced nociceptive response and activated ERK only in nerve-injured mice. BK or B1 agonist-induced activation of ERK in DRG neurons of nerve-injured mice was completely blocked by pretreatment with antisense oligodeoxynucleotide (AS-ODN) for B1 receptor. We found that in sham-operated mice mainly B2 receptors were expressed in unmyelinated DRG neurons with a very little presence of B1 receptor. After nerve injury, B2 receptor expression drastically decreased, whereas B1 receptors were newly expressed mainly in myelinated DRG neurons and satellite cells. Finally, BK nociception in sham-operated mice was blocked by AS-ODN for B2 receptors and that in injured mice by AS-ODN for B1 receptors. Altogether, these findings confirm a switching of receptor and fiber subtype for BK nociception after peripheral nerve injury, which might contribute to the pathobiology of neuropathic pain.

Animals↗
PubMed2003

A general method to select antibody fragments suitable for noncompetitive detection of monovalent antigens.

Previously, immunological detection of a small hapten was only possible in competitive format, which needed a competitor antigen either labeled by a reporter or attached to a carrier protein. Recently, we proposed the open sandwich (OS) immunoassay, a simple immunoassay that can noncompetitively determine monovalent antigen concentration by measuring the antigen-dependent change in a heavy-chain variable region (VH)/light-chain variable region (VL) interaction of an antibody. However, there was a limitation in the assay that the antibody used should have a suitable property such that the VH/VL interaction would become fairly strong along with the addition of antigen. Here, we devised a phage-based "split-Fv system" to rapidly evaluate and select antibody variable region (Fv) fragments that are suitable to OS immunoassay. When three antibodies raised against endocrine disruptor bisphenol A were tested with this system, all were more or less suitable to OS-ELISA. Among them, the best Fv selected was used to construct fusion proteins of VH tethered to an alkaline phosphatase and a tagged VL that can be site-specifically biotinylated to perform direct OS-ELISA. The results showed that the OS-ELISA detects bisphenol A with higher sensitivity than the corresponding competitive assay, also implying that many antibodies to small haptens have suitable properties for OS-ELISA.

Animals↗
PubMed2003

Luminescent and substrate binding activities of firefly luciferase N-terminal domain.

Firefly luciferase catalyzes highly efficient emission of light from the substrates luciferin, Mg-ATP, and oxygen. A number of amino acid residues are identified to be important for the luminescent activity, and almost all the key residues are thought to be located in the N-terminal domain (1-437), except one in the C-terminal domain, Lys529, which is thought to be critical for efficient substrate orientation. Here we show that the purified N-terminal domain still binds to the substrates luciferin and ATP with reduced affinity, and retains luminescent activity of up to 0.03% of the wild-type enzyme (WT), indicating that all the essential residues for the activity are located in the N-terminal domain. Also found is low luminescence enhancement by coenzyme A (CoA), which implies a lower product inhibition than in the WT enzyme. These findings have interesting implications for the light emission reaction mechanism of the enzyme, such as reaction intermediates, product inhibition, and the role of the C-terminal domain.

Adenosine Triphosphate↗
PubMed2003

Locus-specific rescue of GluRepsilon1 NMDA receptors in mutant mice identifies the brain regions important for morphine tolerance and dependence.

Tolerance and physical dependence caused by chronic treatment of narcotics are good models to study basic neuronal plasticity. Activation of the NMDA subtype of the glutamate receptor has been implicated as an anti-opioid system in the development of morphine analgesic tolerance and dependence. The present study examines the specific role of the epsilon1 subunit of the NMDA receptor using mice lacking the gene encoding epsilon1 subunit of the NMDA receptor (GluRepsilon1-/- mice). GluRepsilon1-/- mice showed significant enhancement and prolongation of morphine anti-nociception, compared with wild-type GluRepsilon1+/+ mice. GluRepsilon1-/- mice also showed a marked loss of the analgesic tolerance after repeated morphine treatments. In C57BL/6J mice treated with chronic morphine after tolerance paradigm, the GluRepsilon1 protein expression significantly increased in periaqueductal gray matter (PAG), ventral tegmental area (VTA) and nucleus accumbens (NAc), but not amygdala or hippocampus. The rescue of GluRepsilon1 protein by electroporation into the PAG and VTA, but not NAc of GluRepsilon1-/- mice significantly reversed morphine analgesic tolerance liability. Similar attempts were also performed in the naloxone-precipitated physical dependence paradigm. GluRepsilon1-/- mice showed marked loss of typical withdrawal abstinence behaviors, and significant enhancement of GluRepsilon1 protein expression was only observed in NAc by chronic morphine treatments after dependence paradigm. The rescue of GluRepsilon1 protein by electroporation into the NAc of GluRepsilon1-/- mice significantly reversed the loss of abstinence behaviors. These findings suggest that GluRepsilon1 has locus-specific roles in the development of morphine analgesic tolerance and physical dependence.

Animals↗
PubMed2003

Neuronal necrosis inhibition by insulin through protein kinase C activation.

In the serum-free culture of rat embryonic neurons, most neurons rapidly died by necrosis, which was revealed by propidium iodide (PI)-positive staining as early as 3 h after the start of culture and by marked membrane disruption and mitochondrial swelling in transmission electron microscopic (TEM) analysis. However, neither nuclear condensation/fragmentation stained with Hoechst 33342 nor activated caspase-3-like immunoreactivity was observed. In the serum-deprived culture, on the other hand, neurons showed apoptotic features, such as caspase-3 activation and nuclear damages in TEM analysis. Insulin at relatively higher concentrations, up to 100 microg/ml, ameliorated the rapid decrease in survival activity measured with 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt WST-8 assay and PI staining in the serum-free culture, despite the fact that brain-derived neurotrophic factor and insulin-like growth factor-I had no survival effect even at concentrations up to 100 microg/ml. Insulin-induced survival effects were abolished by the protein kinase C (PKC) inhibitor calphostin C but not by the phosphatidyl inositol-3-OH-kinase inhibitor wortmannin or the mitogen-activated protein kinase inhibitors PD98059 or U0126. Insulin significantly stimulated the PKC activity in cell lysates and suppressed the mitochondrial swelling and membrane disruption in TEM analysis in a calphostin C-reversible manner. All of these findings suggest that insulin inhibited the neuronal necrosis resistant to known neurotrophic factors under the serum-free culture through PKC mechanisms.

Adenosine Triphosphate↗
PubMed2003

The algogenic-induced nociceptive flexion test in mice: studies on sensitivity of the test and stress on animals.

Recently we developed a new technique, known as peripheral nociception test or algogenic-induced nociceptive flexion (ANF) test, to study the in vivo signal transduction of pain at the peripheral nerve endings in mice. In the present report, we examined the sensitivity of the method to detect pain signal and the stresses induced by the test on experimental animals. In the algogenic-induced biting and licking (ABL) test, bradykinin could not induce significant biting-licking response even at a dose of 1nmol. It induced significant biting-licking response only at 10nmol. However, with the ANF test, 100fmol of bradykinin was enough to produce sharp and significant nociceptive flexion response. Similarly, substance P, ATP and ONO-54918-07, a stable prostaglandin I(2) agonist, induced nociceptive flexion response in ANF test at much lower doses than needed to induce biting-licking responses in ABL test. Next, we measured the plasma corticosterone level after different nociception tests, which is a measure of stress on animals due to experimental manipulations. However, no significant rise in corticosterone level was observed with ANF test. Altogether, these findings indicate that the ANF test is a highly sensitive and less stressful technique to study in vivo mechanisms of pain at the peripheral nerve ending.

Adenosine Triphosphate↗
PubMed2003

Increased expression of vanilloid receptor 1 on myelinated primary afferent neurons contributes to the antihyperalgesic effect of capsaicin cream in diabetic neuropathic pain in mice.

Topical capsaicin is believed to alleviate pain by desensitizing the vanilloid receptor 1 (VR1) at the peripheral nerve endings. Here, we report that an up-regulation of VR1 expression on myelinated fibers contributes to the antihyperalgesic effect of capsaicin cream in streptozotocin (STZ)-induced diabetic neuropathic pain. Intravenous injection of STZ (200 mg/kg) in mice caused rapid onset of diabetes within 24 h. Thermal and mechanical hyperalgesia developed by 3 days after STZ injection and persisted at all time points tested until 28 days. There was also hyperalgesic response to intraplantar (i.pl.) prostaglandin I2 (PGI2) agonist-induced nociception in such mice. Application of capsaicin cream dose dependently reversed the thermal, mechanical, and PGI2 agonist-induced hyperalgesia observed in the diabetic mice. The i.pl. injection of capsaicin solution (0.4 microg/20 microl) produced nociceptive biting-licking responses in control mice, and these responses were significantly increased in STZ-induced diabetic mice. After neonatal capsaicin-treatment, which destroys most unmyelinated C-fibers, the i.pl. capsaicin-induced biting-licking responses were almost abolished. However, in neonatal capsaicin-treated diabetic mice, the i.pl. capsaicin-induced biting-licking responses reappeared. The i.pl. capsaicin-induced biting-licking responses were blocked by the competitive VR1 antagonist capsazepine. All these results suggest an increase in capsaicin receptor on myelinated fibers due to diabetes. Finally, we confirmed the up-regulation of VR1 expression on myelinated primary afferent neurons of diabetic mice by immunohistochemistry. Together, our results suggest that increased expression of VR1 on myelinated fibers might contribute to the antihyperalgesic effect of topical capsaicin in diabetic neuropathic pain.

Afferent Pathways↗
PubMed2003

Bypassing antibiotic selection: positive screening of genetically modified cells with an antigen-dependent proliferation switch.

While antibiotic selection has been routinely used for the selection of genetically modified cells, administration of cytotoxic drugs often leads to deleterious effects not only to inert cells but also to transfected or transduced ones. In this study, we propose an Antigen-MEdiated Genetically modified cell Amplification (AMEGA) system employing antibody/receptor chimeras without antibiotic selection. Based on a rational design where the extracellular domains of dimeric erythropoietin receptor (EpoR) or gp130 were substituted with heterodimeric V(H)/V(L) regions of anti-hen egg lysozyme (HEL) antibody and EpoR D2 domains, the genes encoding the chimeras as well as a model transgene, enhanced green fluorescent protein (EGFP), were retrovirally infected into IL-3-dependent Ba/F3 cells followed by direct HEL selection in the absence of IL-3. After a single round of selection, EGFP-positive cells were selectively amplified, resulting in a population of almost 100% positive cells. The AMEGA without antibiotic selection will not harm normal cells, which will be especially useful for increasing the efficacy for stem cell-based gene therapy.

Animals↗
PubMed2003

Nocistatin and prepro-nociceptin/orphanin FQ 160-187 cause nociception through activation of Gi/o in capsaicin-sensitive and of Gs in capsaicin-insensitive nociceptors, respectively.

Nociceptin/orphanin FQ (N/OFQ), nocistatin, and prepro-N/OFQ 160-187 (C-peptide) are all derived from the same precursor protein. We examine the pharmacological mechanisms of nocistatin- and C-peptide-induced pronociceptive responses in a novel algogenic-induced nociceptive flexion test in mice. The intraplantar (i.pl.) injection of nocistatin- and C-peptide induced pronociceptive responses in a range of 0.01 to 10 or 1 pmol, respectively, which showed 100- to 1000-fold less potent effects than the N/OFQ. The nociceptive effects of both peptides were not affected by 1-[(3R,4R)-1-cyclooctylmethyl-3-hydroxymethyl-4-piperidyl]-3-ethyl-1,3-dihydro-2H-benzimidazole-2-one (J-113397) (i.pl.), an N/OFQ receptor antagonist, indicating that they are mediated by a novel mechanism independent of activation of N/OFQ receptor. Like N/OFQ, nocistatin-induced nociception was abolished by i.pl. injection of pertussis toxin, phospholipase C inhibitor, or CP-99994, a neurokinin 1 receptor antagonist, indicating that nocistatin may elicit nociception through a substance P release from nociceptor endings via activation of Gi/o and phospholipase C. The nociception was abolished by neonatal pretreatment (s.c.) with capsaicin or by i.t. pretreatment with CP-99994, but not MK-801 (i.t.), an N-methyl-d-aspartate receptor antagonist. In contrast, C-peptide-induced nociception was attenuated by the pretreatment with antisense oligodeoxynucleotide for Galphas (i.t.) and with KT-5720 (i.pl.), a cyclic AMP-dependent protein kinase inhibitor, but not with pertussis toxin. The nociception was neither attenuated by neonatal capsaicin nor by i.t. injection with CP-99994, but it was attenuated by i.t. injection with MK-801. These results suggest that nocistatin and C-peptide derived from prepro-N/OFQ stimulate distinct nociceptive fibers through different in vivo signaling mechanisms.

Analgesics, Opioid↗
PubMed2003

In vivo pain-inhibitory role of nociceptin/orphanin FQ in spinal cord.

Because nociceptin/orphanin FQ (N/OFQ) has both pronociceptive (hyperalgesia) and antinociceptive actions in pharmacological experiments, and there is no significant difference in the nociceptive responses between NOP(-/-) mice and their wild-type (NOP(+/+)) littermates, the physiological role of N/OFQ in pain regulation remains to be determined. Under the hypothesis that the use of molecularly distinct nociception test may reveal the pain modality-specific role of N/OFQ, we attempted to examine the physiological role of N/OFQ in pain transmission by using newly developed algogenic-induced nociceptive flexion test in NOP(-/-) and NOP(+/+) mice or NOP antagonist-treated mice. The nociceptive flexor responses upon intraplantar injection of bradykinin or substance P, which stimulates polymodal substance P-ergic fibers, were markedly potentiated in NOP(-/-) mice, compared with those in its NOP(+/+) mice. However, there were no significant changes in NOP(-/-) mice with adenosine triphosphate or prostaglandin I(2) agonist, which stimulates glutamatergic but not substance P-ergic fibers. The nocifensive responses induced by substance P (i.t.) were also potentiated in NOP(-/-) mice. On the other hand, there were no significant differences in NK1-like immunoreactivity, [(3)H]substance P binding, or NK1 gene expression in the dorsal horn of the spinal cord between NOP(-/-) and NOP(+/+) mice. In addition, NOP antagonists decreased the threshold in nociception tests driving spinal substance P neurotransmission. All these findings suggest that the N/OFQ-ergic neuron may play an in vivo inhibitory role on the second-order neurons for primary polymodal substance P-ergic fibers in the spinal cord.

Animals↗
PubMed2003

Seasonal changes of responses to gonadotropin-releasing hormone analog in expression of growth hormone/prolactin/somatolactin genes in the pituitary of masu salmon.

Gonadotropin-releasing hormone (GnRH) is considered to stimulate secretion of growth hormone (GH), prolactin (PRL), and somatolactin (SL) at particular stages of growth and sexual maturation in teleost fishes. We therefore examined seasonal variation in the pituitary levels of GH/PRL/SL mRNAs, and tried to clarify seasonal changes of responses to GnRH in expression of GH/PRL/SL genes, in the pituitaries of growing and maturing masu salmon (Oncorhynchus masou). Pituitary samples were monthly collected one week after implantation with GnRH analog (GnRHa). The levels of mRNAs encoding GH, PRL, and SL precursors in single pituitaries were determined by a real-time polymerase chain reaction method. The fork lengths and body weights of control and GnRHa-implanted fish of both sexes gradually increased and peaked out in September of 2-year-old (2+) when fish spawned. GnRHa implantation did not stimulate somatic growth, nor elevate gonadosomatic index (GSI) of 1+ and 2+ males, whereas it significantly increased GSI of 2+ females in late August to early September. The GnRHa-implanted 1+ males had higher levels of GH and PRL mRNAs in July, and SL mRNA from June to August than the control males. The levels of GH, PRL, and SL mRNAs in the control and GnRHa-implanted 1+ females, however, did not show any significant changes. Afterward, the PRL mRNA levels elevated in the control 2+ fish of both sexes in spring. GnRHa elevated the GH mRNA levels in both males and females in 2+ winter, and the PRL mRNA levels in females in early spring. Regardless of sex and GnRHa-implantation, the SL mRNA levels increased during sexual maturation. In growing and maturing masu salmon, expression of genes encoding GH, PRL, and SL in the pituitary is thus sensitive to GnRH in particular seasons probably in relation to physiological roles of the hormones.

Animals↗