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Volume 111, Issue 7
Displaying 1-7 of 7 articles from this issue
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Yukio YONEDA, Kiyokazu OGITA1991 Volume 111 Issue 7 Pages 329-344
Published: July 25, 1991
Released on J-STAGE: May 30, 2008
JOURNAL FREE ACCESSGlutamate (Glu) receptors are classified into two major categories in the mammalian central nervous system : ionotropic receptors linked to ion channels and metabotropic receptors linked to phosphatidylinositol (PI) metabolism. Classification of the ionotropic Glu receptors is based on the differential sensitivity to excitement by N-methyl-D-aspartic acid (NMDA), DL-α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) and kainic acid (KA). The NMDA-sensitive subclass is supposed to be a receptor ionophore complex consisting of at least four different subcomponents, including an NMDA recognition site, a glycine (Gly) recognition site, a polyamine recognition site and a cation channel. The NMDA site is radiolabeled by both Glu and competitive antagonists, such as (±)-3-(2-carboxypiperazin-4-yl) propyl-1-phosphonic acid (CPP) and DL-(E)-2-amino-4-propyl-5-phosphono-3-pentenoic acid (CGP 39653). The Gly domain, which is labeled by both [3H] Gly and [3H] 5, 7-dichlorokynurenic acid, is sensitive to D-serine but insensitive to strychnine, and this domain seems to be absolutely required for an activation of the NMDA channel by agonists. The ionophore domain is identified by radiolabeled noncompetitive NMDA antagonists that gain access to the binding sites within the channel only when it is gated by agonists. The opening of an NMDA channel is allosterically potentiated by Gly and several polyamines. In contrast, an activation of the NMDA channel is blocked by both H+ and divalent cations such as Mg2+ and Zn2+. [3H] AMPA binding displays pharmacological profiles of the AMPA-sensitive subclass with a rank order of agonistic potencies of quisqualic acid (QA)≨AMPA>Glu>KA, which is apparently different from that found for the KA-sensitive subclass (domoic acid ≨KA>QA>Glu). In contrast, several quinoxaline derivatives competitively antagonize neuronal responses mediated not only by the AMPA receptor but also by the KA receptor. The metabotropic Glu receptors, which stimulate PI metabolism through an activation of the guanosine triphosphate-binding proteins, are activated by Glu, QA and trans-1-amino-cyclopentyl-1, 3-di-carboxylic acid (ACPD). Responses mediated by the metabotropic receptors are competitively blocked by 2-amino-3-phosphonopropionic acid. Three or four cloned complementary deoxyribonucleic acids (cDNAs) encoding ionotropic Glu receptors are isolated from a rat brain cDNA library. Pharmacological and electrophysiological properties of receptor-ion channels encoded by a transfection of these cDNAs are similar to those observed with the AMPA receptor as well as the KA receptor, but not with the NMDA receptor.View full abstractDownload PDF (1802K) -
Tadashi YOSHIMOTO1991 Volume 111 Issue 7 Pages 345-358
Published: July 25, 1991
Released on J-STAGE: May 30, 2008
JOURNAL FREE ACCESSSeveral proline specific peptidases were newly isolated from mammalian organs, plants and microorganisms, and their enzymatic properties characterized. The genes of prolyl endopeptidase, aminopeptidase P and proline iminopeptidase from some microorganisms were cloned and their nucleotide sequences determined. By high expression of these genes in Escherichia coli, the enzymes became possible to be used for the industrial application as well as its basic research. Novel inhibitors specific for the prolyl endopeptidase and dipeptidyl aminopeptidase IV were synthesized and some inhibitors for prolyl endopeptidase found to show an anti-amnesic effect.View full abstractDownload PDF (1534K) -
Kenji TOKUNO, Tsutomu OHASHI1991 Volume 111 Issue 7 Pages 359-364
Published: July 25, 1991
Released on J-STAGE: May 30, 2008
JOURNAL FREE ACCESSThe Gabriel reaction in the solid state was studied and found to proceed in high yield. In the solid-state reactions of potassium phthalimide (1) with p-bromophenacyl bromide (2), 2-bromoacetylnaphthalene (3), and p-nitrobenzyl bromide (4), the corresponding N-derivatives, i.e., N-(4-bromophenacyl) phthalimide (7), N-(2-naphthoylmethyl) phthalimide (8), and N-(p-nitrobenzyl) phthalimide (9), were obtained in yields of 96.2%, 99.6%, and 90.1%, respectively. The change of the halogen in a series of p-nitrobenzyl halides showed that the reactivity was in the order of Br>Cl>I. The cleavage of carbonhalogen bonds in the solid-state Gabriel reaction is affected by the ready cleavage of organic halides, the extent of contact between reactants due to grinding, and the activated state produced by a reaction temperature and a mechanical energy such as grinding.View full abstractDownload PDF (622K) -
Hisashi ISHII, Junichi KOBAYASHI, Munekazu ISHIKAWA, Joju HAGINIWA, Ts ...1991 Volume 111 Issue 7 Pages 365-375
Published: July 25, 1991
Released on J-STAGE: May 30, 2008
JOURNAL FREE ACCESSChemical constituents of the root bark of Toddalia asiatica (L.) LAM. (T. aculeata PERS.), Rutaceae, were examined. In addition to twelve known coumarins [toddaculin (2), coumurrayin (5), toddanone (6), 8-(3, 3-dimethylallyl)-6, 7-dimethoxycoumarin (7), isopimpinellin (8), 6-(3-chloro-2-hydroxy-3-methylbutyl)-5, 7-dimethoxycoumarin (9), 6-formyllimettin (10), 5, 7, 8-trimethoxycoumarin (12), toddasin (13), (+)-toddanol (14), 6-(2-hydroxy-3-methoxy-3-methylbutyl)-5, 7-dimethoxycoumarin (18), and toddalolactone (21)] five new coumarins [toddalenol (17), toddalosin (19), 5-methoxysuberenon (23), toddalenone (24), and 8-formyllimettin (25)] were isolated. Furthermore seven known benzo [c] phenanthridine alkaloids [des-N-methylchelerythrine (4), oxychelerythrine (15), arnottianamide (16), oxyavicine (22), avicine (30), chelerythrine (31), and chelerythrine-ψ-cyanide (34)] and four known quinoline alkaloids [N-methylflindersine (11), 4-methoxy-1-methyl-2-quinolone (20), skimmianine (35), integriquinolone (36)], one known triterpenoid [β-amyrin (3)], and four unknown components [unknown I-IV (26)-(29)] were isolated.View full abstractDownload PDF (1072K) -
Hisashi ISHII, Shoji TAN, JianPing WANG, IhSheng CHEN, Tsutomu ISHIKAW ...1991 Volume 111 Issue 7 Pages 376-385
Published: July 25, 1991
Released on J-STAGE: May 30, 2008
JOURNAL FREE ACCESSIt is well known that toddalolactone (1) is a main component of Toddalia asiatica (L.) LAM. (T. aculeata PERS.) (Rutaceae). However, supercritical fluid (SCF) extraction of the plant by using CO2 showed that a main component of the extract was not 1, but aculeatin (2), a coumarin having an epoxy ring on the side chain. The same result was obtained from Soxhlet extraction by using aprotic solvents. On the other hand, Soxhlet extraction by using methanol yielded 13, corresponding to a methanol adduct of 2, as an additional component, which was able to be also produced in 50.2% yield only by heating pure 2 in methanol, indicating that the epoxy ring in 2 can be easily attacked by a weak nucleophile like methanol. These facts strongly suggested that 1, corresponding to the hydrate of 2, was an artefact derived from 2 during extraction. SCF extraction under various conditions was examined in detail by quantitative analyses of 1 and 2 by high performance liquid chromatography and the optimum condition extracting the both components was found to be at 40°C and at 300 kg/cm2. The condition was applied to the plant treated with aqueous sodium hydrogen carbonate in order to remove any acidic substances and 1 was still detected in the extract. Thus, it is conclude that 1 should be a genuine natural coumarin but that previous isolation of 1 as a main component resulted in an isolation of an artefact derived from 2. SCF extraction was suggested to be a useful extraction method.View full abstractDownload PDF (944K) -
Toshihiko YOSHIDA, Yoichi YAMAMOTO, Noriyuki YAGI, Yoshie TAKAHASI, Sh ...1991 Volume 111 Issue 7 Pages 386-392
Published: July 25, 1991
Released on J-STAGE: May 30, 2008
JOURNAL FREE ACCESS5-Amino-7-(2-aminoalkoxy)-1-cyclopropyl-6-fluoro-1, 4-dihydro-4-oxoquinoline-3-carboxylic acid and their derivatives (10, 11) were prepared and their antibacterial activities were evaluated. As a result of in vitro antibacterial screening, the compounds having mono-or di-methyl (11d, e) group at α-position of amino group were most effective among the 7-aminoalkoxy derivatives. Structure-activity relationship of these compounds is also discussed.View full abstractDownload PDF (633K) -
Kimie IMAI, Kashie KANEMOTO, Naoto INOUE, Tachio AIMOTO1991 Volume 111 Issue 7 Pages 393-396
Published: July 25, 1991
Released on J-STAGE: May 30, 2008
JOURNAL FREE ACCESSThe effect of pretreatment with protoporphyrin IX (PP) on the impairment of hepatic mitochondrial respiration induced by carbon tetrachloride (CCl4) was studied in rats. Treatment of animals intraperitoneally with CCl4 resulted in marked impairment of states 4 and 3 respirations, respiratory control and oxidative phosphorylation of mitochondria in the presence of succinate, β-hydroxybutyrate or glutamate as substrates. The PP, given intravenously, caused no alterations in those mitochondrial functions. The treatment with PP prior to the administration of CCl4 inhibited the induction of mitochondrial respiratory impairment by CCl4. CCl4 increased markedly the contents of lipid peroxide in the liver but not those in the mitochondria. The increase of hepatic lipid peroxides by CCl4 was markedly reduced by the pretreatment with PP. These results indicate that PP effectively protects the mitochondria from the functional disorder caused by CCl4.View full abstractDownload PDF (548K)
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