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121.
K Nonogaki A Iguchi X Li T Tamagawa G Watanabe Y Hiyoshi N Sakamoto 《Life sciences》1992,51(12):PL131-PL134
We previously reported that when neostigmine, an inhibitor of acetylcholine esterase, was injected into the third cerebral ventricle, the concentration of hepatic venous plasma glucose was increased via central muscarinic receptors in anesthetized rats. To determine whether brain histamine receptors are involved in cholinergic system transmission with regard to central nervous system (CNS)-mediated glucoregulation, we examined the effects of the H1 receptor antagonist pyrilamine and the H2 receptor antagonist ranitidine on neostigmine-induced hyperglycemia in anesthetized rats. The injection of pyrilamine (5 x 10(-9)-5 x 10(-7) mol) into the third cerebral ventricle suppressed hyperglycemia induced by intraventricular injection of neostigmine (1 x 10(-9) mol) in a dose-dependent manner. Injection of ranitidine (5 x 10(-9)-5 x 10(-7) mol) into the third cerebral ventricle did not suppress the hyperglycemia induced by neostigmine, but enhanced it in a dose-dependent manner. These findings suggest that neostigmine-induced CNS-mediated hyperglycemia is transmitted by not only brain cholinergic muscarinic receptors but also in part by histamine H1 receptors. 相似文献
122.
Akihiro Kondo John Sidney Scott Southwood Marie-France del Guercio Ettore Appella Hiroshi Sakamoto Howard M. Grey Esteban Celis Robert W. Chesnut Ralph T. Kubo A. Sette 《Immunogenetics》1997,45(4):249-258
Previous studies have defined two different peptide binding motifs specific for HLA-A
*
0101. These motifs are characterized by the presence of tyrosine (Y) at the C-termini of 9-mer and 10-mer peptides, and either
a small polar or hydrophobic (S, T, M) residue in position 2, or a negatively charged (D or E) residue in position 3. In this
study, the structural requirements for peptide binding to A
*
0101 have been further analyzed by examining the binding capacity of large sets of peptides corresponding to naturally occurring
sequences which bore one or the other of these two A
*
0101-specific motifs. By correlating the presence of specific residue types at each position along the peptide sequence with increased
(or decreased) binding affinity, the prominent influence of secondary anchor residues was revealed. In most cases, the two
anchors in positions 2 and 3 appear to act synergistically. With the exception of the DE3 submotif in 9-mer peptides, a positive role for aromatic residues in position 1 and the center of the peptide (positions
4 or 5 of 9- or 10-mer peptides, respectively), and proline at C-3, were also consistently detected. However, secondary anchor
residues also appear to differ significantly between the two different submotifs, demonstrating that A
*
0101 can utilize alternative modes in binding its peptide ligands. According to these analyses, specific refined submotifs were
also established, and their merit verified by independent sets of potential A
*
0101 binding peptides. Besides providing useful insight into the nature of the interaction of the A
*
0101 allele with its peptide ligands, such refined motifs should also facilitate accurate prediction of potential A
*
0101-restricted peptide epitopes.
Received: 16 July 1996 / Revised: 18 September 1996 相似文献
123.
Martens JR Sakamoto N Sullivan SA Grobaski TD Tamkun MM 《The Journal of biological chemistry》2001,276(11):8409-8414
The precise subcellular localization of ion channels is often necessary to ensure rapid and efficient integration of both intracellular and extracellular signaling events. Recently, we have identified lipid raft association as a novel mechanism for the subcellular sorting of specific voltage-gated K(+) channels to regions of the membrane rich in signaling complexes. Here, we demonstrate isoform-specific targeting of voltage-gated K(+) (Kv) channels to distinct lipid raft populations with the finding that Kv1.5 specifically targets to caveolae. Multiple lines of evidence indicate that Kv1.5 and Kv2.1 exist in distinct raft domains: 1) channel/raft association shows differential sensitivity to increasing concentrations of Triton X-100; 2) unlike Kv2.1, Kv1.5 colocalizes with caveolin on the cell surface and redistributes with caveolin following microtubule disruption; and 3) immunoisolation of caveolae copurifies Kv1.5 channel. Both depletion of cellular cholesterol and inhibition of sphingolipid synthesis alter Kv1.5 channel function by inducing a hyperpolarizing shift in the voltage dependence of activation and inactivation. The differential targeting of Kv channel subtypes to caveolar and noncaveolar rafts within a single membrane represents a unique mechanism of compartmentalization, which may permit isoform-specific modulation of K(+) channel function. 相似文献
124.
Mice lacking serum amyloid P component do not necessarily develop severe autoimmune disease 总被引:4,自引:0,他引:4
Soma M Tamaoki T Kawano H Ito S Sakamoto M Okada Y Ozaki Y Kanba S Hamada Y Ishihara T Maeda S 《Biochemical and biophysical research communications》2001,281(1):200-205
Interleukin-10 (IL-10) is a cytokine with many regulatory functions. In particular, IL-10 exerts neutralizing effect on other cytokines, and therefore IL-10 is thought to have important therapeutic implications. Recent reports suggest that IL-10 regulates not only immunocytes but also collagen and collagenase gene expression in fibroblasts. In this study, we investigated the effect of IL-10 on gene expression of extracellular matrix (ECM) proteins, such as type I collagen, fibronectin, and decorin, in human skin fibroblasts. Results of Northern blot analysis showed that both collagen I and fibronectin mRNAs were downregulated, while decorin gene expression was enhanced by IL-10 (10 ng/ml) time-dependently (6-24 h). alpha1(I) collagen and fibronectin mRNAs were decreased to one-third and one-fourth, respectively, by 50 ng/ml IL-10, whereas decorin mRNA was increased up to 2.7-fold by 50 ng/ml IL-10. Response to IL-10 by scleroderma fibroblasts was similar to that in normal dermal fibroblasts, with decreased expression levels of collagen and fibronectin and induced decorin mRNA levels. Transforming growth factor-beta (TGF-beta) is a crucial fibrogenic cytokine which upregulates the mRNA expression of collagen and fibronectin, whereas it downregulates decorin mRNA expression in fibroblasts. Monocyte chemoattractant protein-1 (MCP-1) has recently been shown to upregulate the type I collagen mRNA expression in cultured fibroblasts. We therefore examined whether IL-10 alters gene expression of ECM elicited by TGF-beta and MCP-1. Our results demonstrated that IL-10 downregulated the TGF-beta-elicited increase of mRNA expression of type I collagen and fibronectin, while partially recovering TGF-beta-elicited decrease of decorin expression in normal skin fibroblasts. By contrast, IL-10 did not alter the MCP-1-elicited upregulation of mRNA expression of either alpha1(I) collagen and decorin. Our data indicate that IL-10 differentially regulates TGF-beta and MCP-1 in the modulation of ECM proteins and therefore suggest that IL-10 plays a role in the regulation of tissue remodeling. 相似文献
125.
Nakamura T Houchi H Minami A Sakamoto S Tsuchiya K Niwa Y Minakuchi K Nakaya Y 《Life sciences》2001,69(15):1709-1715
The relaxation effect of cilostazol, a phosphodiesterase III inhibitor, on the thoracic aorta was investigated. Cilostazol induced the relaxation of the thoracic aorta precontracted by phenylephrine in a concentration-dependent manner. The concentration-dependent relaxation was shifted to the right in the endothelium denuded aorta compared with that of intact endothelium, suggesting that this relaxation was partly dependent on endothelium. Cilostazol-induced relaxation of thoracic aorta tone was reversed by treatment with N(G)-nitro L-arginine (L-NNA), a competitive inhibitor of nitric oxide (NO) synthase. Cilostazol also significantly increased the NO level in the porcine thoracic aorta. In rats treated with cilostazol, the urinary excretion of nitrites, a stable metabolite of NO, and basal production of NO of the aortic ring were significantly greater than in those without treatment. These findings indicate that cilostazol-induced vasodilation of the rat thoracic aorta was dependent on the endothelium, which released NO from aortic endothelial cells. 相似文献
126.
Effects of the angiotensin-converting enzyme (ACE) inhibitors, imidapril and enalapril, on kaolin-induced writhing reaction, which is believed to be caused by bradykinin (BK), were examined in mice. The number of writhes was increased significantly by 200 microg/kg of imidapril and by 100 and 200 microg/kg of enalapril. The intensity of writhing reaction was significantly suppressed by 1,000 nmol/kg of icatibant, a selective bradykinin B2 receptor antagonist, in the imidapril-, but not in the enalapril-treated groups. These results suggest that the potentiating effect of enalapril on kaolin-induced writhing reaction is greater than that of imidapril. This might depend on the difference of their inhibitory effects on BK degradation. 相似文献
127.
Kawada T Nakatsuru Y Sakamoto A Koizumi T Shin WS Okai-Matsuo Y Suzuki J Uehara Y Nakazawa M Sato H Ishikawa T Toyo-oka T 《FEBS letters》1999,457(3):405-408
We found that 5-S-GAD, an insect-derived antibacterial peptide, inhibited murine osteoclast formation in vitro. We examined the specific time point of the inhibitory action of 5-S-GAD on osteoclast formation and found that it mainly suppressed differentiation of osteoclasts in the middle of the culture period. Using HL60 cells that are able to differentiate into multinucleated macrophage-like cells, we found that 5-S-GAD induced apoptosis of HL60 cells by producing H(2)O(2). Thus, the inhibition of osteoclast formation by 5-S-GAD could be, in part, due to apoptosis of the cells of an osteoclast lineage. 相似文献
128.
Y Tanaka T Hori M Katahira F Nishikawa T Sakamoto Y Fukunaga Y Kurihara S Nishikawa S Uesugi 《Nucleic acids symposium series》1999,(42):221-222
Three variants of minimized hepatitis delta virus (HDV) RNA ribozyme systems (Rz-1 to approximately Rz-3) (Fig. 1) were designed on the basis of the "pseudoknot" structure model and synthesized. Rz-1 is a cis-acting ribozyme system (a cleaved form, 56-mer) in which stem IV is deleted from the active domain of genomic HDV RNA. Rz-1 was uniformly labeled with stable isotopes, 13C and 15N. The 2D-NOESY and 2D-HSQC data for Rz-1 suggest that Rz-1 forms the pseudoknot structure and G38 which is opposite to the cleavage site makes a base-pair. Rz-2 is a trans-acting ribozyme system which consists of three RNA oligomer strands (substrate: 8-mer, the cytidine residue at the cleavage site is replaced by 2'-O-methylcytidine; enzyme: 16-mer plus 35-mer). Rz-3 is a ribozyme in which the three RNA strands of Rz-2 are connected. It turns out that Rz-3 forms an inactive structure with low cleavage activity (k(obs) = 0.009) and final cleavage yield (6%). Rz-3 has the highest cleavage activity at pH 5.5. The optimal activity at acidic pH is similar to that of the wild type ribozyme. We also synthesized and examined the activity and structure of Rz-4 (designed by Perrotta and Been) which consists of two RNA strands (1). 相似文献
129.
M Sakamoto T Koseki M Umeda I Ishikawa Y Benno T Nakase 《Microbiology and immunology》1999,43(7):711-716
A total of 74 strains of oral treponemes, which were isolated from subgingival plaque samples from patients with periodontitis, were taxonomically studied on the basis of biochemical characteristics, DNA-DNA hybridization, and 16S rRNA gene sequences. These organisms fermented carbohydrates and required rumen fluid or short-chain volatile fatty acids for growth. The isolates were divided into seven subgroups based on their biochemical characteristics. The levels of DNA relatedness among the representative strains of each subgroup and Treponema socranskii (including three subspecies) were greater than 78%, while the levels of DNA relatedness among these strains and other Treponema species, including T. denticola and "T. vincentii", were less than 15%. DNA-DNA hybridization indicated that all subgroups belonged to T. socranskii. This result correlated well with the cluster on the phylogenetic trees based on 16S rRNA sequences. 相似文献
130.
Sakamoto A 《Molecular and cellular biochemistry》2004,259(1-2):183-187
Cardiomyopathy is primary degenerative disease of myocardium, which leads to cardiac failure and lethal arrhythmia. An appropriate model animal of a particular disease is, in general, greatly helpful for better understanding of its pathogenesis. In 1962, a naturally occurring mutant line of Syrian hamster named BIO1.50 was reported, which inherited cardiomyopathy and muscular dystrophy as autosomal recessive mode with 100% penetrance. To date, several sublines of cardiomyopathic hamsters (CM hamsters) have been derived. The genomic deletion of delta-sarcoglycan, a member of dystrophin-associated proteins, was demonstrated to be the common genetic cause of CM hamsters in 1997. Over the past 40 years, hundreds of papers have been published on the pathophysiological aspects of CM hamsters. The aim of this paper is to annotate every one of the CM hamsters with its historical background and then summarize the previous findings on CM hamsters with special focus on electrical and ionic properties. This review article is expected to serve as a basis to build up a new paradigm for the pathogenesis of cardiac failure and severe arrhythmia. 相似文献