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Y Nagumo

Publications and source records attributed to Y Nagumo.

16 recordsLinked to original sources
PubMed2006

Age-related emotionality is associated with cortical delta-opioid receptor dysfunction-dependent astrogliosis.

Multiple changes occur in the aging brain, leading to age-related emotional disorders. A growing body of recent evidence suggests that the cortical delta-opioid receptor system plays a critical role in anxiety- and depressive-like behaviors in the rodent. In this study, we show that aging mice promoted anxiety-like behaviors as characterized by both the light-dark and elevated plus-maze tests, and they exhibit an increase in astrocytes in the cingulate cortex due to the dysfunction of cortical delta-opioid receptor systems. As well as aging mice, mice with a dysfunction of the delta-opioid receptor system induced by chronic treatment with the selective delta-opioid receptor antagonist naltrindole, revealed astrogliosis in the cingulate cortex, which was associated with anxiety. We also found that the microinjection of cultured astrocytes into the cingulate cortex of young mice enhanced the expression of anxiety-like behavior. Our results indicate that the aging process promotes astrogliosis in the cingulate cortex through the dysfunction of cortical delta-opioid receptors. This phenomenon may lead to emotional disorders including aggravated anxiety during normal aging.

Aging↗
PubMed2005

Involvement of mitogen-stimulated p70-S6 kinase in the development of sensitization to the methamphetamine-induced rewarding effect in rats.

The neural plasticity associated with behavioral sensitization following repeated administration of a psychostimulant methamphetamine (METH) is thought to require synthesis of new proteins. The aim of the present study was to investigate the role of p70-S6 kinase (p70-S6K) phosphorylation, which contributes to the selective translation of a unique family of mRNA, in mediating both the METH-induced rewarding effect and its sensitization. An intra-nucleus accumbens (N.Acc.) pre-injection with 0.025 pmol/rat of a selective p70-S6K inhibitor rapamycin failed to affect the METH-induced conditioned place preference. However, this treatment clearly abolished the development of sensitization of the METH-induced conditioned place preference. Consistent with the behavioral assay, the level of the immunoreactivity of phosporylated-p70-S6K was not changed in the cytosolic fraction of the N.Acc. obtained from rats that had revealed the METH-induced rewarding effect. In contrast, the immunoreactivities in the cytosolic preparation for Western blotting and immunohistochemical density of phosphorylated-p70-S6K were significantly increased in the N.Acc. obtained from METH-sensitized rats as compared with those with chronic saline treatment. However, the immunoreactivities of phosphorylated-extracellular signal-regulated kinase and phosphorylated-ribosomal S6 protein were not significantly altered in the N.Acc. under the same condition. The present data provide evidence for the change in the translation rate, which can be regulated by S6K phosphorylation, in the N.Acc. during the development of sensitization to METH-induced rewarding effects in rats.

Animals↗
PubMed2004

Implications of protein kinase C in the nucleus accumbens in the development of sensitization to methamphetamine in rats.

Repeated treatment with methamphetamine leads to an enhancement in the methamphetamine-induced dopamine release and its related behaviors. This phenomenon is called sensitization or reverse tolerance. Protein kinase C (PKC) controls numerous signaling cascades by virtue of its ability to phosphorylate target proteins that include other kinases. The purpose of study was then to investigate the implication of PKC in the development of sensitization to the rewarding effect and to the extracellular dopamine release induced by methamphetamine in rats. The conditioned place preference paradigm and in vivo microdialysis assay were performed in the present study. An intra-nucleus accumbens injection of a selective PKC inhibitor chelerythrine chloride abolished the enhancement of the methamphetamine-induced place preference following repeated treatment with methamphetamine. Furthermore, intra-nucleus accumbens injection of chelerythrine chloride blocked the development of sensitization to dopamine release and to the decrease in the major dopamine metabolites, 3'4-dihydroxyphenylacetic acid and homovanillic acid, in the nucleus accumbens induced by repeated methamphetamine treatment. Under these conditions, the immunoreactivity of the cytosolic phosphorylated conventional- or classic-type PKC in the limbic forebrain region including the nucleus accumbens was slightly, but significantly increased in methamphetamine-sensitized rats. The present data provide evidence for the implication of PKC in the nucleus accumbens in the development of sensitization to the methamphetamine-induced rewarding effect, dopamine release and inhibition of dopamine metabolism/re-uptake in rats.

Animals↗
PubMed2001

Concise synthesis of ciguatoxin ABC-ring fragments and surface plasmon resonance study of the interaction of their BSA conjugates with monoclonal antibodies.

Monoclonal antibodies (mAbs), 4H2 and 6H7, were prepared previously using a protein conjugate of a 1:1 epimeric mixture of the synthetic ABC-ring fragments of ciguatoxin (CTX), 3 and 4. Here, the interactions of these mAbs with the fragments of CTX and CTX3C, 3 and 5, were investigated by surface plasmon resonance (SPR) spectroscopy in an attempt to clarify an antigenic determinant. Compared with the previous synthesis, the fragment 3 possessing the 2S configuration was synthesized from tri-O-acetyl-D-glucal much more effectively. The mAb 4H2 was already known to show a dose-dependent binding to the bovine serum albumin (BSA) conjugate of 3, but not to that of 5. The present SPR study of 4H2 demonstrates that the A-ring side chain of 3 plays a decisive role as an epitope. Therefore, SPR can effectively replace the ELISA method for the analysis of mAbs.

Antibodies, Monoclonal↗
PubMed2000

T7 RNA polymerase activation and improvement of the transcriptional sequencing by polyamines.

We examined the possibility to improve the effectiveness of the in vitro transcription system using T7 RNA polymerase by coexistence with organic bases. The effect of the additives was evaluated by measuring the amount of RNA products in comparison with that of the control system (without additive). We found that four commercial bases and a series of ethylated polyamine analogues newly designed were active enhancers in the following activation order, 1,8-bis(ethylamino)octane > 1,8-octanediamine > 1,5-bis(ethylamino)pentane > cadaverine > 1,8-bis(ethylamino)-4-azaoctane > spermidine 1,18-bis(ethylamino)-5,14-diazaoctadecane > agmatine. It was shown that RNA products were corresponding, only in the presence of active enhancers, to the full length size of the template DNA, and that sequencing signals were enhanced by the presence of active enhancers with high fidelity so that the transcriptional sequencing was further refined to be a highly sensitive sequencing method from a small amount of linear dsDNA. These results suggest that T7 RNA polymerase was activated by the specific binding of the polyamine additive to produce RNA transcripts with fidelity to the template DNA. Therefore, it is expected that the transcriptional sequencing in the presence of active enhancers might be a powerful and sensitive method, in place of the prevalent DNA amplification method, for genomic science projects and clinical and practical gene diagnoses.

DNA↗
PubMed1994

[Three dimensional architecture of the microvascular systems of the skin in wound healing processes of normal and streptozotocin-induced diabetic rats].

Fine vascular architectures in the wound healing process of streptozotocin (STZ)-induced diabetic rat skin were studied by scanning electron microscope with newly designed high pressure resin injection method. In the normal rat skin, the new method successfully demonstrated the hitherto unknown subepidermal fine capillary network which continuously surrounded the pillosebaceous tissues. In wound healing processes after combined resection of skin and fascia, vascular regeneration occurred from both the border and the base of the lesion. The new vasculatures from the border of dermis demonstrated concentric array of loops extending toward the center of the lesion. The direct budding emerged from the capillary network of the exposed muscle surface. Subepidermal vasculatures of the intact back skin of STZ-induced diabetic rats showed coarse and poorer network pattern. Increased number of anastomoses between arterioles and venules, insufficiently dilated arterioles distal to the A-V shunt were the other findings which may imply the increased shunt blood flow and consequent poor peripheral dermal circulation.

Animals↗